ABSTRACT: PurposeSudden cardiac death after ejaculation has been reported in humans and highlights the important relationship between sexual
behavior and the heart. The rat is an extremely useful animal model for investigating reproductive function in male mammals.
In this study, we examined the relationship between autonomic nervous system activity and the circulatory system during sexual
behavior in male rats.
MethodsMale Wistar–Imamichi rats were exposed to female rats in estrous and heart rate (HR), systolic blood pressure (SBP), diastolic
blood pressure (DBP), and plasma noradrenaline (NA) and adrenaline (Ad) concentrations were measured by telemetry during copulation.
ResultsThe resting HR was 365.5±18.4beats/min (mean±SE), which increased to 531.2±21.1beats/min at ejaculation and decreased
to 404.6±30.7beats/min 1min after ejaculation. At rest, SBP and DBP were 123.8±6.6 and 81.5±4.1mmHg, respectively,
which increased to 154.5±5.9 and 112.1±7.3mmHg at ejaculation. Baseline plasma Ad and NA concentrations were 151.6±32.0
and 248.5±22.5pg/ml, respectively, and these increased to 393.8±89.9 and 792.7±154.0pg/ml at ejaculation, after which
they decreased to resting levels. The rate of increase in NA at ejaculation differed significantly from that of Ad.
ConclusionsThe load on the circulatory and autonomic nervous systems is controlled by a rapid decrease in HR and NA concentration immediately
after ejaculation, such that the male rat is prepared for the next copulation.
Reproductive Medicine and Biology 04/2012; 8(2):59-62.
ABSTRACT: PurposeThe dopamine-derived endogenous compound, R-salsolinol (SAL), was recently identified as a putative endogenous prolactin (PRL)-releasing
factor. However, how SAL influences copulatory behavior is unknown. In this study, we examined the relationship between SAL
and copulatory behavior in male rats.
MethodsMale Sprague-Dawley rats administered SAL were exposed to female rats in estrus, the plasma PRL concentration was measured,
and the behavioral frequency and time during copulatory behavior were noted.
ResultsIn the control and SAL groups, plasma PRL concentrations at 15min before exposure to the female were 7.3±2.0 and 8.0±1.5ng/ml,
respectively. Moreover, plasma PRL concentrations in males immediately after exposure to the female were 7.4±1.2 and 68.0±5.9ng/ml,
respectively (P<0.05). All (8/8) of the control animals ejaculated in the presence of the female, whereas only 33% (2/6) of the SAL group
ejaculated. An increasing tendency for mount latency and intromission latency and a decreasing tendency for intromission frequency
were observed in the SAL group.
ConclusionsCopulatory behavior was inhibited in male rats after SAL injection, suggesting that SAL is a copulatory behavior inhibiting
KeywordsCopulatory behavior-Hyperprolactinemia-Male rat-Prolactin-releasing factor-Salsolinol
Reproductive Medicine and Biology 04/2012; 9(4):205-209.
ABSTRACT: We investigated the effects of a bioartificial endocrine pancreas (Bio-AEP) produced by mouse beta cells on sexual dysfunction of streptozotocin (STZ)-induced diabetic female rats. Female rats were administered STZ (60 mg/kg BW, i.v.) at the age of 10 weeks and transplanted with a Bio-AEP including mouse beta cells at the age of 14 weeks (STZ+Bio-AEP group). Lordosis and proceptive sexual behavior of female rats were observed. The results showed that after the Bio-AEP transplant blood glucose recovered from 380-450 mg/dl induced by streptozotocin to 140-230 mg/dl and suppressed lordosis and proceptive behavior also recovered. These results suggest that it is possible to reverse sexual dysfunction by continuous administration of mouse insulin.
Experimental Animals 01/2010; 59(4):515-9. · 0.92 Impact Factor
ABSTRACT: In this study, in order to clarify the kinetics of leptin, we focused on the ratio of leptin concentrations in cerebrospinal fluid and serum in aged male rats, and examined the weight of epididymal fat, and the passage rate of leptin through the blood-brain barrier. In the lighter animals, the epididymal fat weight was low, while leptin concentrations in the serum and cerebrospinal fluid were also low. Conversely, in the heavier animals, the weight of epididymal fat and leptin concentrations in the serum and cerebrospinal fluid were higher. With regard to the ratio of leptin in the cerebrospinal fluid and serum, the passage rate of leptin through the blood-brain barrier was lower in the heavier animals than in the lighter animals.
Experimental Animals 11/2008; 57(5):485-8. · 0.92 Impact Factor
ABSTRACT: The present study aimed to clarify the connection between immune responses and the administration frequency of methamphetamine (MAP) in male and female mice. Male and female ddY mice were given single or multiple (repeated for 10 days) intraperitoneal injections of MAP (5.0 mg/kg/day). The following immune parameters were examined; the number of leukocytes in peripheral blood and the proliferative activity (phytohemagglutinin;PHA, lipopolysaccharide; LPS response) and natural killer (NK) cell activity in splenic lymphocytes. Further, the differences in metabolic function in the spleen in response to MAP (and its metabolite amphetamine) in male and female mice were measured by gas chromatography. The results of the present study were that; 1) single and repeated MAP injections reduced leukocytes; 2) single MAP injection increased the proliferative response of splenic lymphocytes to PHA stimulation in only male mice, but the response to LPS stimulation was slightly increased in both male and female mice; 3) single and repeated MAP injections reduced NK cell activity of splenic lymphocytes, and especially in female mice with 5 injections of MAP; 4) with 10 MAP injections the NK cell activity and leukocytes recovered to the level of controls; and 5) the metabolic activity of MAP was reduced in female mice treated acutely with MAP in comparison to male mice. These results appear to indicate that immune responses to MAP were involved in the different results shown for administration frequency, sex difference and metabolic process of MAP.
Experimental Animals 02/2008; 57(1):35-43. · 0.92 Impact Factor
ABSTRACT: Ontogenetic changes of USVs were investigated to establish an index of stress in infant rats. The USVs were obtained by exposing infant rats to cold stress and were analyzed by real-time spectrography. USV waveforms consisted of four types, R-I, II, III and IV. These USVs were closely monitored at the age of 3-7 days in both sexes. From day 14, the frequency and incidence of USVs gradually decreased and had disappeared completely at the age of 21 days. Therefore, USVs should be useful in estimating the stress of infant rats between the ages of 3-7 days.
Experimental Animals 08/2007; 56(4):315-8. · 0.92 Impact Factor