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Adjuvant effects of classical music on simvastatin induced reduction of anxiety but not object recognition memory in rats

Authors:
  • Universidade da Região de Joinville

Abstract

Simvastatin is one of many hydroxymethylglutaryl-coenzyme-A reductase inhibitors that are prescribed to lower cholesterol. Some emerging evidence indicates that classical music can serve as an effective adjuvant in rats treated with simvastatin. Moreover, simvastatin or classical music have been shown to influence some cognitive functions. To further understand the mechanisms of action, we exposed rats to classical music for 1 month, and then treated them orally with simvastatin. The behavioral experiments suggested that exposure to subchronic simvastatin (1 or 10 mg/kg/day) reduced anxiety levels in the elevated plus-maze and open-field test in rats exposed to Mozart music. The recognition object test results indicated that simvastatin altered non-spatial working memory only at the 1 mg/kg/day dose and improved both short and long-term object recognition. No significant differences were found between Mozart music and silence in the object recognition test, suggesting that music did not significant affect learning and memory in adult rats. We hypothesize that the anxiolytic, but not object recognition memory, effects of simvastatin and classical music effects occur through similar mechanisms, providing an important foundation for future preclinical and clinical research.
Psychology & Neuroscience, 2013, 6, 3, 403 - 410
DOI: 10.3922/j.psns.2013.3.19
Anice Milbratz de Camargo, Débora Delwing Dal Magro,
Johanna Kleis Seubert, and José Geraldo Pereira da Cruz,
Departamento de Ciências Naturais, Universidade Regional
de Blumenau, Blumenau, SC, Brazil. Daniela Delwing de
Lima, Departamento de Farmácia, Universidade da Região
de Joinville, Joinville, SC, Brazil. Júlia Niehues da Cruz,
Departamento de Medicina, Universidade do Extremo Sul
Catarinense, Criciúma, SC, Brazil. Correspondence regarding
this article should be directed to: José Geraldo Pereira da Cruz,
Departamento de Ciências Naturais, Universidade Regional
de Blumenau, Rua Antônio da Veiga, 140, Blumenau, 89012-
900, Santa Catarina, Brazil; Phone: +55 047 3321 0272; Fax:
+55 047 3321 0233; E-mail: jgcruz@furb.br
Introduction
Simvastatin has been widely used clinically
to reduce serum low-density lipoprotein (LDL)
cholesterol by inhibiting the rate-limiting enzyme,
hydroxymethylglutaryl-coenzyme reductase. The
neuroprotective effects of statins have also been
suggested in several studies. Compared with other
statins, simvastatin is more lipophilic and more easily
permeates the blood-brain barrier, which could offer a
further neuroprotective effects (Hayashi et al., 2005;
Sierra, Ramos, Molina, Esteo, Vázquez, & Burgos,
2011; Urban et al., 2009). Additionally, evidence
indicates that simvastatin reduces the risk of ischemic
heart disease and cerebrovascular stroke, with potential
applications in multiple sclerosis, traumatic brain injury,
Alzheimer’s disease, and anxiety and potential effects
on cognition (Baytan et al., 2008, Carrocini et al.,
2012; Sett, Robinson, & Mistri, 2011; Swindle, Potash,
Kulakodlu, Kuznik, & Buikema, 2011; Tramontina et
al., 2011; Wang et al., 2009; Zhang, Tao, Troiani, &
Markovic-Plese, 2011). Despite growing evidence of the
role of simvastatin in central nervous system diseases,
relatively little knowledge is available about its direct
neuropsychological effects on central receptors and
association with anxiolytic-like behavioral effects and
cognitive decline associated with neurodegenerative
diseases (Carrocini et al., 2012; Jukema, Cannon, de
Craen, Westendorp, & Trompet, 2012).
Clinical reports indicate that music can be an
effective treatment for numerous disorders. Music
therapy has shown promising results for cognition. It has
also been shown to be useful as an adjunct therapy for
addiction and for the treatment of anxiety, chronic stress,
pain, sleep disorders, autism, depression, psychosis,
and posttraumatic stress disorder (Bernatzky, Presch,
Anderson, & Panksepp, 2011; Chan, Chan, & Mok,
Adjuvant effects of classical music on simvastatin induced
reduction of anxiety but not object recognition memory in
rats
Anice Milbratz de Camargo1, Daniela Delwing de Lima2, Débora Delwing Dal Magro1, Johanna
Kleis Seubert1, Júlia Niehues da Cruz3,and José Geraldo Pereira da Cruz1
1. Universidade Regional de Blumenau, Blumenau, SC, Brazil
2. Universidade da Região de Joinville, Joinville, SC, Brazil
3. Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil
Abstract
Simvastatin is one of many hydroxymethylglutaryl-coenzyme-A reductase inhibitors that are prescribed to lower cholesterol.
Some emerging evidence indicates that classical music can serve as an effective adjuvant in rats treated with simvastatin.
Moreover, simvastatin or classical music have been shown to influence some cognitive functions. To further understand the
mechanisms of action, we exposed rats to classical music for 1 month, and then treated them orally with simvastatin. The
behavioral experiments suggested that exposure to subchronic simvastatin (1 or 10 mg/kg/day) reduced anxiety levels in the
elevated plus-maze and open-field test in rats exposed to Mozart music. The recognition object test results indicated that
simvastatin altered non-spatial working memory only at the 1 mg/kg/day dose and improved both short- and long-term object
recognition. No significant differences were found between Mozart music and silence in the object recognition test, suggesting
that music did not significant affect learning and memory in adult rats. We hypothesize that the anxiolytic, but not object-
recognition memory, effects of simvastatin and classical music effects occur through similar mechanisms, providing an important
foundation for future preclinical and clinical research. Keywords: anxiety, elevated plus-maze, music, object recognition, open-
field, simvastatin.
Received 18 September 2012; received in revised form 22 July 2013; accepted 24 July 2013. Available online 23 December 2013.
404 Camargo et al.
2010; Chan,Wong, & Thayala, 2011; Cruz, Dal Magro,
& Cruz, 2010; Gold, Solli, Krüger, & Lie, 2009; Polston,
Rubbinaccio, Morra, Sell, & Glick, 2011; Raglio et al.,
2012; Wan, Demaine, Zipse, Norton, & Schlaug, 2010).
Music can enhance medical therapies and be used as an
adjuvant with other anxiety-management programs to
increase the effectiveness of those therapies (Raglio et
al., 2012). However, although musical appreciation is
well documented in the human population, signicant
disagreement still exists in the literature about whether
this is conned to the human species or extends to
other members of the animal kingdom. Considering the
enormous potential that music therapy offers, a growing
need exists to develop preclinical models.
Research conducted in our laboratory suggests that
subchronic simvastatin treatment reduces anxiety levels
in rats when associated with Mozart music. Our study
the rst to show that is statins combined with music have
anxiolytic-like effects in the elevated plus-maze (Cruz,
Lima, Dal Magro, & Cruz, 2011). A possible mechanism
of action for these effects may involve the modulation
of N-methyl-D-aspartate (NMDA) receptors (Wang et
al., 2009; Xu, Yu, Cai, Zhang, & Sun, 2009; Yan et al.,
2011). These results indicate that music can serve as
an effective adjuvant in rats treated with simvastatin,
and this species may potentially be used in other
preclinical models that utilize musical interventions.
Additionally, the mechanisms by which simvastatin and
music exert their benecial effects may be related to
the modulation of the signaling pathways involved in
memory formation. Surprisingly, a relative paucity of
such preclinical studies is available, particularly with
regard to anxiety and memory.
The present study sought to conrm and extend
these ndings. We examined the effects of Mozart music
combined with simvastatin in rats using a range of
behavioral paradigms. A battery of two different anxiety
tests was used for the rst paradigm, which is thought
to reect anxiety states in humans. These consisted of:
the elevated plus-maze (Pellow, Chopin, File, & Briley,
1985) and open-eld test (Prut & Belzung, 2003). To
assess memory, the novel object recognition test was
used. This model is thought to measure non-spatial
working memory in rats (Ennaceur, 2010).
Methods
Subjects
A total of 60 male genetically heterogeneous albino
Wistar rats (Rattus norvegicus), 3 to 5 months and
weighing 220 to 310 g, were obtained from the animal
house of the Regional University of Blumenau. After
arrival in the vivarium of the laboratory, these animals
were housed in groups of ve per opaque plastic cage
(50 x 30 x 15 cm) with wood shaving bedding and
wire mesh tops. They were housed under a standard
(12 h/12 h light/dark; cycle lights on at 7:00 AM), in
a temperature-controlled environment (23 ± 1ºC), with
a 50 dB background sound level, and 55±10% relative
humidity. During the light and dark phases, the rats were
exposed to light intensities of approximately 500 and
0,025 lux, respectively. These lux values were chosen
because they were the light intensities that were closest
to natural daytime and nighttime light in our laboratory.
During the entire experimental period, the animals
received commercial chow for rodents (Nuvital, Paraná,
Brazil) and ltered tap water ad libitum. At irregular
intervals the room was visited an average of once every
2 or 3 days clean the cages, and provide food and water.
The animals were acclimated to the animal housing
facilities for at least 1 week before the experiments
began. The experiments were performed in compliance
with the recommendations of the Brazilian Society of
Neuroscience and Behavior (SBNeC), which are based
on the United States National Institutes of Health Guide
for Care and Use of Laboratory Animals.
Experimental protocols
The rats were divided into two groups: silence and
music. They were randomized with 10 rats per group
and orally received either simvastatin (1 or 10 mg/kg/
day by oral gavage, Zocor; Merck KGaA, Darmstadt,
Germany) or saline, control group, for 4 consecutive
weeks. The rats in the auditory enriched conditions
were exposed to music for 5 h/day, between 12:00
and 5:00 PM. The music (i.e., Mozart’s piano sonata,
KV361, Largo, 8:35 min duration) was continuous and
repeated on a compact disc player (Cruz et al., 2010).
The speaker had a frequency range of 100-16000 Hz.
The silent room was exactly the same as the room in
which music was played but no sound was made, with
the exception of ambient noises such as those produced
by the air conditioner. The sound levels for the silence
and music groups were 50 dB (ambient noise) and 65-
75 dB, respectively, in the home cages and behavioral
apparatus. After 4 weeks the rats in each subgroup were
selected for the behavioral studies.
Behavioral tests
The animals were individually subjected to
the elevated plus-maze, open-eld test and object
recognition test. All of the behavioral procedures were
conducted during the light phase (between 1:00 and
4:00 PM), in a sound-isolated room, when the rodents
were less active. To minimize possible circadian
inuences, the experimental and control observations
were alternated. The observer stayed in the same room,
approximately 1 m away from the apparatus (Ennaceur,
2010; Pellow et al., 1985; Prut & Belzung, 2003). The
tests were conducted under dim red light (44 lux).
Elevated plus-maze test
The apparatus consisted of two open arms (50 x 10
cm) and two closed arms (50 x 10 x 40 cm) arranged
such that the two arms of each type were opposite to each
other, with a central platform (10 x 10 cm). The height
of the maze was 50 cm. The animals were exposed for 5
min to the red light in their own home cages before the
Music and simvastatin 405
testing procedure. They were then individually placed
on the central platform of the elevated plus-maze facing
an open arm. During a 5 min test period the following
parameters were recorded by an observer: time spent on
the open arms, number of entries into the open arms,
time spent on the closed arms, number of entries into the
closed arms and risk assessment (Pellow et al., 1985).
Risk assessment is a measure that accounts for the time
spent head-dipping (i.e., exploratory movements of the
head/and shoulders over the side of the maze) and in
a stretched attend posture (i.e., exploratory posture in
which the body is stretched forward and then retracted to
the original position without any forward locomotion).
The measures that reect anxiety-like behavior in this
test are the entries into the open arms vs. closed arms
and time spent on the open arms vs. closed arms. We
also included ethologically derived measures related
to the defensive pattern of risk assessment behavior,
which has been shown to be very sensitive to changes
in anxiety.
Open-field test
The open-eld consisted of a black circular box
(60 cm diameter, 50 cm height). Each rat was placed
in the central area and allowed to freely explore the
apparatus for 5 min. Every time both hind paws entered
one square, a crossing was recorded. The total distance
traveled by the animals was estimated by the number of
squares crossed. Ambulation time (i.e., movement from
one location to another), the time spent immobile (i.e.,
completely immobile), the time spent rearing (the rat
stood on its hind paws with its body at greater than a
45° angle to the oor) and the time spent grooming (i.e.,
repetitive movements of the front paws or mouth on the
fur) were also recorded (Prut & Belzung, 2003).
Object recognition test
The object recognition test measures non-spatial
working memory in rats and takes advantage of the
unprompted nature of rats to explore their surroundings
(Ennaceur, 2010). This model is advantageous because
it does not require punishment or reward and is quick
and simple to implement. The rats were rst exposed
to two identical objects. After a specic delay, the rat
was then presented with one of the familiar objects and
a novel object. When a rat “remembers” the previous
exposure to the familiar object, it will explore the novel
object to a greater extent than the familiar one. All of
the animals were habituated to the experimental arena
in the absence of any specic behavioral stimulus for
20 min/day for 4 days. The objects, were made of metal
or glass, and afxed to the arena’s oor with adhesive
tape. In the pretest two identical objects (M and N) were
placed in the corners of the box. The test was repeated
2 h later to valuate short-term memory or 24 h later
to evaluate long-term memory after the pretest. In the
tests, one of the objects was changed for a new object
(P for short-term memory; R for long-term memory).
The time allowed for exploration in each trial was 5
min. The positions of the objects (familiar or novel)
were randomly permuted for each experimental animal
and the arena was cleaned between trials. Exploration
was dened as snifng or touching the object with the
nose or forepaws. Sitting on or turning the object was
not considered exploratory behavior. The time spent
exploring each object was recorded by an observer
who was blind to treatment and is expressed as total
exploration time (in seconds).
Statistical analysis
All of the data are expressed as ± S.E.M. Each value
reects the mean of 10 animals per group. The means
were compared using analysis of variance (ANOVA),
followed by the Newman-Keuls multiple comparison
test. A probability level of .05 was used as the criterion
for statistical signicance.
Results
The ANOVA revealed signicant differences
between subgroups in the time spent on the open arms
of the elevated plus-maze (F = 4.160; p< .01). Music-
exposed rats that received simvastatin (1 or 10 mg/kg)
exhibited an increased time spent on the open arms
compared with the silence/0 mg/kg simvastatin (p<
.05, Figure 1A). However, no signicant difference was
observed between groups in the time spent the closed
arms (F = .7562; p> .05; Figure 1B). Music exposure
signicantly increased the number of open arm entries
in rats that received 1 or 10 mg/kg simvastatin compared
with the silence/0 mg/kg simvastatin (F = 5.483; p<
.001 and p< .01; respectively; Figure 1C). No signicant
difference was found between groups, in the number of
closed arm entries (F = .9901; p> .05; Figure 1D) or risk
assessment (F = 1.275; p> .05; Figure 1E).
The ANOVA revealed signicant differences
between groups ambulation time in the open-eld
(F = 8.350; p< .001). Music-exposed that received
simvastatin (1 or 10 mg/kg) exhibited an increased
ambulation time compared with the silence/0 mg/kg
simvastatin group (p< .01 and p< .001; respectively;
Figure 2A). Additionally, music exposure signicantly
increased the distance traveled at simvastatin doses
of 1 and 10 mg/kg (F = 4.052; p< .05; Figure 2B) and
decreased the time spent immobile (F = 6.195; p< .05
and p< .01; respectively; Figure 2C). No signicant
difference was found between groups, in the time spent
rearing (F = 1.680; p> .05; Figure 2D) or time spent
grooming (F = 1.146; p> .05; Figure 2E).
The ANOVA revealed a signicant enhancement
of non-spatial learning in the object recognition test.
Rats in the silence group (F = 3.916; p< .01) and music-
exposed group (F = 4.804; p< .01), that received 1 mg/
kg simvastatin, exhibited improvements in both short-
term and long-term object recognition memory (p<
.05; Figure 3A and B). However, in the silence group
that received saline (F = .1476; p> .05) or 10 mg/kg
simvastatin (F = 1.690; p> .05), as well as the group
music treated with saline (F = 0.3299; p>0,05) or 10
406 Camargo et al.
Figure 1. Effect of simvastatin (1 and 10 mg/kg/day) on anxiety-like behavior in rats under each sound condition (silence and
music) in the elevated plus-maze. (A) Time spent on the open arms. (B) Time spent on the closed arms. (C) Number of open arm
entries. (D) Number of closed arm entries. (E) Risk assessment. The data are expressed as mean ± SEM (n = 10/group). *p< .05,
**p< .01, ***p< .001 (ANOVA followed by Newman-Keuls test).
Silence
Silence
Silence
Silence
Silence
Music
Music
Music
Music
Music
160
120
80
40
0
Time spent in open arm (s)
Time spent in open arm (s)
Number of open arm entries
Number of open arm entries
Risk assessment time (s)
0 1 10 0 1 10
0 1 10 0 1 10
0 1 10 0 1 10
0 1 10 0 1 10
0 1 10 0 1 10
mg/kg Sim
mg/kg Sim
mg/kg Sim
mg/kg Sim
mg/kg Sim
(A)
(C) (D)
(E)
(B)
10
8
6
4
2
0
200
160
120
80
40
0
100
80
60
40
20
0
15
12
9
6
3
0
mg/kg simvastatin (F = 2.421; p> .05), exhibited no
alterations in short- or long-term memory.
Discussion
The present results suggest that subchronic
treatment with simvastatin reduced anxiety levels
in rats when associated with Mozart music. Music
exposure combined with simvastatin increased the time
spent on the open arms and entries into the open arms
of the elevated plus-maze (Figure 1). An increased
time spent on the open arms and entries into the open
arms of the elevated plus-maze are interpreted as a
reduction of anxiety-like behavior (Pellow et al., 1985).
The differences in anxiotypic behavior expressed by
these animals are not limited to their performance on
the elevated plus-maze. A novel environment is used
to establish general anxiotypic behavior, and levels of
locomotion in this paradigm can be used as indices of an
anxiety-like state in rats (Prut & Belzung, 2003). Music
combined with 1 or 10 mg/kg simvastatin increased
ambulation time and the distance traveled and reduced
the time spent immobile in the open-eld (Figure 2),
indicating increased exploratory activity.
This result is consistent with other studies in which
male Wistar rats that were subcronically treated with
the same doses of simvastatin exhibited a reduction of
anxiety when associated with Mozart music, exposure
24 h before the behavioral tests (Cruz et al., 2011).
Several physiological mechanisms have been suggested
to explain the benecial effects of simvastatin on
anxiety (Wang et al., 2009; Yan et al., 2011). A possible
mechanism that mediates these effects may involve the
modulation of NMDA receptors in Sprague-Dawley
rats (Wang et al., 2009; Xu et al., 2009; Yan et al.,
Music and simvastatin 407
Figure 2. Effect of simvastatin (1 or 10 mg/kg/day) on locomotor activity and exploratory behavior of rats under each sound
conditions (silence or music) in the open-eld test. (A) Ambulation time. (B) Distance traveled. (C) Time spent immobile. (D)
Time spent rearing. (E) Time spent grooming. The data are expressed as mean ± SEM (n = 10/group). *p< .05, **p< .01, ***p<
.001 (ANOVA followed by Newman-Keuls test).
Figure 3. Effect of simvastatin (1 or 10 mg/kg/day) on learning and memory in rats under each sound conditions (silence or
music) in the object recognition test. (A) Exploration time in silence group. (B) Exploration time in music group. The rats
were exposed to two identical objects (M and N) in the pretest session. Two hours later, a short-tem memory (STM) test was
performed, in which the animals were exposed to a familiar object (M) and a novel object (P). Long-term memory (LTM) was
assessed 24 h after pretest, in which the animals were exposed again to the familiar object (M) and to another novel object (R).
The data are expressed as mean ± SEM (n = 10/group). *p< .05, signicant difference between groups (Newman-Keuls test).
Silence
Silence
Silence
Silence Music
Sim 0 mg/kg
Sim 1 mg/kg
Sim 10 mg/kg
Sim 0 mg/kg
Sim 1 mg/kg
Sim 10 mg/kg
Time Exploration (s)
Time Exploration (s)
Silence
Silence
Music
Music
Music Music
Music
Time spent immobility (s) Time spent ambulation (s)
Distance traveled (m)
Time spent gromming (s)
Time spent rearing (s)
0 1 10 0 1 10 0 1 10 0 1 10
0 1 10 0 1 10 0 1 10 0 1 10
0 1 10 0 1 10
mg/kg Sim mg/kg Sim
mg/kg Sim mg/kg Sim
mg/kg Sim
(A) (B)
(C) (D)
(E)
(A)
(B)
M N
M N
M P
M P
M P
M P M P
M PM R
M R
M R
M R M R
M R
M N
M N M N
M N
160
120
80
40
0
30
25
20
15
10
5
0
70
60
50
40
30
20
10
0
250
200
150
100
50
0
8
6
4
2
0
75
50
25
0
75
50
25
0
408 Camargo et al.
2011). Another possible mechanism may involve the
modulation of cholesterol distribution within brain cell
membranes (Kirsch, Eckert, & Mueller, 2003). Because
of the relatively high concentration of cholesterol in
the brain, the detection of changes that are specic to
membrane cholesterol is difcult. However, evidence
indicates that chronic simvastatin administration does
not change cholesterol levels in brain tissue or plasma
in rodents (Mok et al., 2006; Wang et al., 2009). The
effects of simvastatin in central nervous system may
be hypothesized to occur via a central mechanism
that is independent of hypocholesterolemic properties
(Johnson-Anuna et al., 2005; Schoonjans, Peinado-
Onsurbe, Fruchart, Tailleux, Fiévet, & Auwerx, 1999).
The literature is inconsistent with regard to whether
animals “appreciate” music, but such a determination
is not necessary for the utilization of music in
animal models of anxiety. In fact, it may prove to be
advantageous if the subjects do not experience pleasure
from the music alone, because this would further
complicate analyses and interpretations. Although the
hearing range of rats and humans is different, 1-100
kHz and 20 Hz to 20 kHz, respectively, we found that
music created for humans can also lead to behavioral
changes in rats (Heffner & Heffner, 2007). Rats are
able to discriminate musical passages, processing of
melodic contour and speaker variability in phonetic
boundaries (Otsuka, Yanagi, & Watanabe, 2009;
Ruusuvirta, Koivisto, Wikgren, & Astikainen, 2007;
Toro, Trobalon, & Sebastián-Gallés, 2005). However,
unknown are the specic features of music, such as
timbre, tempo, key, modulating frequency, rhythm,
or some combination thereof, that are integral to its
efcacy in rats. Additionally, complex acoustic stimuli
engage multiple brain regions beyond primary sensory
areas, including centers for arousal, emotion, and
reward (Blood & Zatorre, 2001). However, our goal
was not to determine whether rats have an appreciation
for Mozart; instead, we sought to determine whether a
complex musical passage can be effectively used as an
adjuvant anxiolytic in rats treated with simvastatin in
the elevated plus-maze and open-eld test.
Pleasurable music evokes neurological responses
that are similar to the effects induced by anxiolytic drugs.
Specically, highly enjoyable music and simvastatin
induce cerebral activation in anxiety-related brain
regions, such as the amygdala (Blood & Zatorre, 2001;
Yan et al., 2011). The amygdala has been linked to many
functional systems in the mammalian brain, including
neuromodulatory, autonomic, endocrine, limbic, and
neocortical circuits. Because of the anatomical position
of the amygdala and its extensive reciprocal and diverse
neural projections, it serves as a hubo of sensory affective
neurotransmission. Furthermore, the amygdala performs
concatenate functions that facilitate communication
between sensory encoding, interpretative systems,
motor planning, and determination pathways (Balleine
& Killcross, 2006). Decades of research have implicated
the amygdala as the neural substrate responsible for
regulating and modifying behaviors in an adaptive
manner that favors the most advantageous outcomes
possible. Therefore, the anxiolytic effects likely result
from positive emotional experiences elicited by pairing
simvastatin administration with music. Emotion-
related behavioral responding can be viewed as the
coordinated processing of amygdaloid nuclei. The
basolateral amygdala encodes and retrieves the affective
value of environmental stimuli, and directs complex
adaptive behavioral responses to an older central
amygdala system that enables cortical structures to
recruit incentive motivational processes and invigorate
emotional responding (Everitt, Cardinal, Parkinson, &
Robbins, 2003).
We were interested in determining the effects
of simvastatin combined with classical music
on non-spatial learning. Testing this aspect of
exploratory behavior allowed to further characterize
the possible effects of simvastatin and Mozart
music on responses to novelty. Our results showed
that simvastatin inuenced learning and memory
processes independently of Mozart music. The object
recognition test indicated that simvastatin altered
non-spatial working memory in Wistar rats only at the
1 mg/kg/day dose and improved both short- and long-
term object recognition memory (Figure 3). However,
no signicant differences were found between
Mozart music and silence in the object recognition
test, suggesting that music did not signicantly affect
learning and memory in adult rats.
Numerous studies reported that statins improved
cognition in mice (Li, Cao, Kim, Lester, & Fukuchi. 2006),
possibly by modulating of signaling pathways implicated
in synaptic plasticity and spatial memory formation
(Vaughan, 2003). Notably, increased levels of NMDA
receptors following chronic simvastatin treatment have
been reported in rats (Wang et al. 2009). Additionally, we
reported that treating hippocampal slices with simvastatin
for several hours increased the magnitude of NMDA
receptor-dependent long-term potentiation, a mechanism
that is thought to mediate memory at the cellular level,
in the CA1 region in young adult C57BL/6 mice (Mans,
Chowdhury, Cao, McMahon, & Li, 2010).
Object recognition memory, depends on the
perirhinal cortex. Whether it is a hippocampus or non-
hippocampus-dependent task is still debatable. Some
studies reported that the task does not require the
hippocampus, but several studies support the hypothesis
that the hippocampus contributes to learned object
familiarity (Mumby, Glenn, Nesbitt, & Kyriazis, 2002;
Roecker et al., 2012).
NMDA receptors play an important role in
learning and memory (Magnusson & Cotman, 1993).
Neurogenesis in the dentate gyrus (Lu et al., 2007),
angiogenesis (Pooler, Xi, & Wurtman, 2006) and
brain-derived neurotrophic factor production (Wu et
al., 2008) are stimulated by chronic statin treatment.
Statins have been used clinically to ameliorate cognitive
decits in different neurodegenerative disorders such as
Music and simvastatin 409
Parkinson’s disease, Alzheimers disease and vascular
dementia (Cramer, Haan, Galea, Langa, & Kalbeisch,
2008; Carlsson et al., 2008). The cumulative reduction
of anxiety patients occurs independently of the
cholesterol-lowering effect of statins (Young-Xu, Chan,
Liao, Ravid, & Blatt, 2003). However, more scientic
investigations, both preclinical and clinical are needed to
specically determine the effects of statins on cognition.
Several important clinical implications emerged with
the nding that simvastatin augmented the behavioral
effects of classical music in the elevated plus-maze and
open-eld test. The anxiolytic-like behavioral effects of
simvastatin combined with Mozart music indicated that
the neural circuitry associated with these effects may
be similar. The conceptual hypothesis that simvastatin
and music produce behavioral effects through similar
mechanisms provides an important direction for future
clinical research. For example, the results suggest that
simvastatin, similar to NMDA antagonists, combined
with classical music possesses anxiolytic effects
in preclinical tests that predict of clinical efcacy.
This is particularly relevant for anxiolytic treatment
in benzodiazepine-resistant patients who develop
hypocholesterolemia (Cruz et al., 2012; Carrocini et al.,
2012; Santos et al., 2012).
Recently, much attention has been devoted to the
glutamatergic system and NMDA receptor antagonists
in particular (RiazaBermudo-Soriano, Perez-Rodriguez,
Vaquero-Lorenzo, & Baca-Garcia, 2012). The results of
these studies may be important for continuing to distinguish
the preclinical and clinical behavioral effects of different
types of anxiolytic drugs. This may suggest that our efforts
should be shifted to the pursuit of new glutamatergic (or
other alternative) compounds rather than remaining on
the well-trodden path of aminobutyric acid-ergic drug
development if we hope to identify truly novel drugs with
unique and improved therapeutic proles.
In summary, the present results strongly indicate that
simvastatin combined with classical music improved
coping with aversive situations, leading to a reduction of
anxiety and indicating a synergistic effect of combination
therapy. However, our results showed that simvastatin
inuenced learning and memory processes independently of
Mozart music. The present study indicates that simvastatin
combined with classical music may have sufcient
construct, face, and predictive validity to become an
interesting ¨pathological” model for pharmacotherapeutic
approaches to the treatment of anxiety-like disturbances
supporting the view that statins may prevent or improve
cognitive decline in animals and humans.
Competing Interests
The authors declare that they do not have any
nancial or nonnancial competing interests.
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... Twenty-one studies investigated the effects of music on behavioral outcomes (see Table 3) (Rauscher et al., 1998;Morton et al., 2001;Chikahisa et al., 2006Chikahisa et al., , 2007Kim et al., 2006;Angelucci et al., 2007a;Feduccia and Duvauchelle, 2008;Meng et al., 2009;Xu et al., 2009;Amagdei et al., 2010;Li et al., 2010;da Cruz et al., 2011;de Camargo et al., 2013;Escribano et al., 2014;Cruz et al., 2015;Jiang et al., 2016;Lee et al., 2016;Xing et al., 2016a,b,c;Yazdani et al., 2016)-specifically learning abilities, anxiety-related behavior and stereotypic behavior as investigated by behavioral tests explained in Supplementary Material III. ...
... Music interventions enhanced learning abilities of rodents, specifically those involved with spatial learning (Rauscher et al., 1998;Chikahisa et al., 2006;Kim et al., 2006;Xu et al., 2009;Amagdei et al., 2010;Jiang et al., 2016;Lee et al., 2016;Xing et al., 2016a,b,c;Yazdani et al., 2016). Moreover, music statistically significantly decreased anxiety-related behavior in seven out of nine studies (Angelucci et al., 2007a;Chikahisa et al., 2007;Meng et al., 2009;Li et al., 2010;de Camargo et al., 2013;Escribano et al., 2014;Cruz et al., 2015); the remaining two studies found no differences between music and comparator groups (Amagdei et al., 2010;da Cruz et al., 2011). The anxietydecreasing effect of music diminished after ovariectomy and was restored by progesterone (Chikahisa et al., 2007;Escribano et al., 2014). ...
... The anxietydecreasing effect of music diminished after ovariectomy and was restored by progesterone (Chikahisa et al., 2007;Escribano et al., 2014). Music seemed to enhance anxiolytic effects of simvastatin (da Cruz et al., 2011;de Camargo et al., 2013). Influence of music on stereotypic behavior was investigated in two studies; music enhanced stereotypic behavior after administration of methamphetamine, but not of saline (Morton et al., 2001;Feduccia and Duvauchelle, 2008). ...
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Background: There is rapidly emerging interest in music interventions in healthcare. Music interventions are widely applicable, inexpensive, without side effects, and easy to use. It is not precisely known how they exert positive effects on health outcomes. Experimental studies in animal models might reveal more about the pathophysiological mechanisms of music interventions. Methods: We performed a systematic review of experimental research in rodents. The electronic databases EMBASE, Medline(ovidSP), Web-Of-Science, PsycINFO, Cinahl, PubMed publisher, Cochrane, and Google scholar were searched for publications between January 1st 1960 and April 22nd 2017. Eligible were English–written, full-text publications on experimental research in rodents comparing music vs. a control situation. Outcomes were categorized in four domains: brain structure and neuro-chemistry; behavior; immunology; and physiology. Additionally, an overview was generated representing the effects of various types of music on outcomes. Bias in studies was assessed with the SYRCLE Risk of Bias tool. A meta-analysis was not feasible due to heterogeneous outcomes and lack of original outcome data. Results: Forty-two studies were included. Music-exposed rodents showed statistically significant increases in neuro-chemistry, such as higher BDNF levels, as well as an enhanced propensity for neurogenesis and neuroplasticity. Furthermore, music exposure was linked with statistically significantly improved spatial and auditory learning, reduced anxiety-related behavior, and increased immune responses. Various statistically significant changes occurred in physiological parameters such as blood pressure and (para)sympathetic nerve activity following music interventions. The majority of studies investigated classical music interventions, but other types of music exerted positive effects on outcomes as well. The SYRCLE risk of bias assessment revealed unclear risk of bias in all studies. Conclusions: Music interventions seem to improve brain structure and neuro-chemistry; behavior; immunology; and physiology in rodents. Further research is necessary to explore and optimize the effect of music interventions, and to evaluate its effects in humans.
... Classical music, particularly by Mozart, has demonstrated effects on cortisol levels (14,15), modulation of the HPA axis as well as the immune system (16) in humans. Experimental studies with the exposure to music from this particular composer showed reduction of hypertension (17) and anxiety isolatedly in rodents (18) and also when combined with medication (19). ...
... The rats of MG and CPMG groups were exposed to classical music for 5 hours / day between 1:00 and 6:00 PM, during the 15 days of trial. Mozart's music (Serenade N.10 in B flat major for woodwinds and bass, "Gran partita" K.361 / 370a, Largo movement, 8:35 minutes long) was continuous and repeated in a CD player (compact disc) (19). The speaker had a frequency range of 100-16000 Hz and the music room had a sound level of 65-75 dB. ...
... The fear induces an avoidance behavior, which in turn makes the animals prefer the closed arms (25). We also included ethologically derived measures related to the defensive pattern of risk assessment behavior, which has been shown to be very sensitive to changes in anxiety (19,26). ...
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The effect of cocoa powder and subchronic exposure to classical music in Wistar rats behavior on anxiety evaluation tests and their antioxidant activity was evaluated. The animals were divided into four groups: control group (CG), cocoa powder group (CPG), music group (MG) and cocoa powder with music group (CPMG). During 15 days, CPG and CPMG received commercial non-alkalized cocoa powder daily (66 mg total polyphenols / g of product, by oral gavage), while MG and CPMG were exposed to the music of Mozart (Serenade N.10 in B flat major for woodwinds and bass, "Gran partita" K.361 / 370a, Largo movement, 8:35 minutes long). At the end of the experiment, the animals were submitted to elevated plus-maze (EPM) and openfield (OF) tests, and serum analysis of thiobarbituric acid reactive substances index (TBA-RS) and the activity of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Animals from MG and CPMG groups showed the highest total horizontal locomotion and more time spent at the central area and reduced immobility time at the OF. The TBA-RS average of the treated groups were lower than the GC. The average activity of CAT was higher in CPMG than the others, and the average activity of SOD and GSH-Px were higher only in CPG and CPMG. We concluded that the treatment with this classical music showed mild anxiolytic activity. Both treatments (coc oa and music) improved serum antioxidant status, but the peripheral activity of different serum enzymes was mainly improved by the cocoa powder .
... It is well documented that NMDA receptors in the brain have a close correlation with anxiety-like activity (Bergink, van Megen, Westenberg, 2004;Chojnacka-Wójcik, Kłodzinska, Pilc, 2001). Modulation of NMDA receptors activity after SIM treatment could explain the drug's anxiolytic-like effects (Camargo et al., 2013;Carrocini et al., 2012;Cruz et al., 2011;Kilic et al., 2012;Pauleti et al., 2013;Santos et al., 2012;Wang et al., 2009;Yan et al., 2011). This hypothesis could be supported by the fact that altered levels of NMDA receptors in the hippocampus and amygdala directly influence anxiety behaviors (Barkus et al., 2010;Blundell, Adamec, 2007;Masneuf et al., 2014). ...
... Additionally, chronic SIM treatment in rats stimulates the production of brain-derived neurotrophic factor in the hippocampus after traumatic brain injury by activating Akt-mediated signaling (Wu et al., 2008), as well as increases NMDA receptor levels, promotes neurogenesis, and increases cerebral blood flow by up-regulating vascular growth factor, synaptophysin, Akt, and ERK (Chen et al., 2003;Wang et al., 2009). However, numerous pre-clinical studies led to the hypothesis that hypofunctional NMDA receptors may also play an important role in the mechanism of anxiolytic actions after SIM treatment (Camargo et al., 2013;Carrocini et al., 2012;Cruz et al., 2011;Pauleti et al., 2013;Santos et al., 2012;Wang et al., 2009;Yan et al., 2011). Accordingly, the functional consequence of such regulation on NMDA receptor function varies on the basis of both the identity of the G protein coupled receptor, and the cell type in which relevant receptors are expressed. ...
... Reduction of the availability of NMDA receptors to interact with NMDA or its physiological ligand glutamate is one mechanism that might mediate the anxiolytic activity of SIM. Our results also provide strong evidence that chronic high-dose SIM administration has NMDA antagonist-like effects, which would partially explain the anxiolytic effects of this drug (Camargo et al., 2013;Carrocini et al., 2012;Cruz et al., 2011;Pauleti et al., 2013;Santos et al., 2012). ...
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Membrane/lipid rafts (MLRs) are plasmalemmal microdomains that are essential for neuronal signaling and synaptic development/stabilization. Inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme-A reductase (statins) can disable the N-methyl-D-aspartate (NMDA) receptor through disruption of MLRs and, in turn, decrease NMDA-mediated anxiety. This hypothesis will contribute to understanding the critical roles of simvastatin in treating anxiety via the NMDA receptor. © 2017, Faculdade de Ciencias Farmaceuticas (Biblioteca). All rights reserved.
... Thus, it has been suggested that the effects of music intervention are important to regulate behaviors including, but not limited to, emotion [19]. In fact, several studies have shown that music is able to induce favorable effects on numerous pathologies and in preclinical models, including, but not limited to, schizophrenia, anxiety, and depression [20][21][22][23][24][25][26][27][28][29][30]. For example, PAS exposure induced reduction in geriatric depression scores in humans [31], and it has been suggested that PAS may be useful to more effective and targeted treatments for depression [28]. ...
... Moreover, previous studies have proposed that the effectiveness of treatments for several disorders, including neuropsychiatric diseases, may be enhanced by other interventions, such as positive environmental activities, exposure to natural compounds, or exposure to patterned auditory stimuli [26,27,50,51]. There are examples in the literature of the use of PAS, particularly (though not limited to) classical music, to induce cognitive improvement and protect against or reduce stress or anxiety symptoms, as well as for neuropsychiatric disorder interventions [20][21][22][23][24][25][26][27][28][29][30]. Among the PAS used in human and in rodent studies, Mozart's pieces have received attention for their effect on spatial memory (i.e., [52][53][54]). ...
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Several interventions have been shown to counteract the effects of stress that may be related to improved neuroplasticity and neuronal activation. In this sense, environmental enrichment (ENR) protects against acute stress and increases neuroplasticity. It has been suggested that the use of patterned auditory stimuli (PAS) may be beneficial in increasing the effectiveness of ENR on disorders related to stress, such as depression and anxiety. Examples of PAS are classical music compositions that have interesting effects at both clinical and preclinical levels. Thus, we analyzed the effects of the exposure to PAS, represented in this study by Mozart’s compositions, during ENR housing for 35 days in adult male Balb/C mice to evaluate depression-associated behavior using the forced-swim test (FST) paradigm with an additional short exposure to PAS. We found that the ENR mice that were exposed to PAS during both housing and behavioral task (ENR + PAS/FST + PAS) show decreased immobility and the number of despair episodes within a higher latency to show the first bout of immobility. Additionally, we found increased neuronal activation evaluated by the identification of activity-regulated cytoskeleton-associated protein- (Arc-) labeled cells in the prefrontal cortex (PFC) in mice exposed to PAS during housing and in the absence or presence of PAS during FST. Moreover, we found increased neuronal activation in the auditory cortex (AuCx) of mice exposed to PAS during FST. Our study suggests that the exposure to PAS during an emotional challenge decreases despair-like behavior in rodents that were previously housed in an enriched environment in combination with auditory stimuli. Thus, our data indicate that the role of the exposure to PAS as an intervention or in combination with positive environment to aid in treating neuropsychiatric disorders is worth pursuing.
... Müziğin sıçan ve farelerdeki etkisini inceleyen davranış çalışmalarında müzik dinleyen gruplarda uzamsal öğrenmenin arttığı (20,22,26,35,38,43,(51)(52)(53)(54)(55)(56)(57), anksiyetenin ise azaldığı (39,41,(58)(59)(60)(61)(62) gözlenmiştir. Farelerde K.448 dinletilerek uzamsal öğrenme ve bellekte uzun süreli artış görülmüştür (55). ...
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