Article

Pre- but not post-menopausal female CBA/CaJ mice show less prepulse inhibition than male mice of the same age.

Department of Brain & Cognitive Sciences, University of Rochester, Rochester, NY 14627, USA.
Behavioural Brain Research (Impact Factor: 3.33). 01/2008; 185(2):76-81. DOI: 10.1016/j.bbr.2007.07.014
Source: PubMed

ABSTRACT Prepulse inhibition (PPI) of the acoustic startle reflex (ASR) has been reported to be weaker in females than males for both humans and rats. Although there are exceptions, on balance these data suggest that PPI is sensitive to sex-specific neurosteroids; in contrast, most studies with mice have not replicated this effect. We compared PPI for noise decrement prepulses (quiet gaps) in female CBA/CaJ mice at 3-8 months (pre-menopausal: n = 55) and 17-25 months of age (post-menopausal, n = 33) with similarly aged groups of males (n = 48, 35). Both PPI and ASR levels were significantly reduced in pre-menopausal females compared to young males, but did not differ between post-menopausal females and old males. The observed PPI decrement in young female mice compared to young males agrees with one previous report in young C57BL/6J mice as well as the majority of studies with human subjects and some strains of rats. The absence of a sex difference in PPI for old mice is consistent with the hypothesis that PPI is affected by reproductive hormones present at high levels only in pre-menopausal females. We note that this effect size for PPI is small, perhaps consistent with reports that the PPI decrement in females is restricted to certain times within the menstrual cycle in women and the estrous cycle in rats. The negative findings previously reported in the mouse can be attributed to the small effect size and to procedural differences, including stimulus conditions, and the different strains and ages of mice.

0 Bookmarks
 · 
89 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: HIV infection is frequently comorbid with methamphetamine (METH) dependence. Both factors are associated with impairment in inhibitory function that continues even after abstinence from the drug. Deficits in prepulse inhibition (PPI), a measure of sensorimotor gating, are induced by acute stimulant administration, but the combined effect of HIV and chronic METH exposure on PPI is not well characterized. We quantified baseline acoustic startle and PPI in mice expressing the HIV-1 gp120 envelope protein (gp120tg) and in wild-type (WT) littermates; thereafter, we administered a chronic regimen of METH or vehicle and tested startle and PPI after 7 days of drug withdrawal. We hypothesized that METH-treated gp120tg mice would exhibit PPI deficits compared with vehicle-treated WT or gp120tg animals. Before METH administration, drug-naive female gp120tg mice exhibited decreased PPI compared with female WT mice, whereas male gp120tg mice exhibited increased startle compared with other groups. After drug withdrawal, no consistent genotype effect was observed, but METH-treated mice exhibited increased PPI compared with vehicle, in contrast to previous reports of acute METH-induced PPI deficits. In summary, PPI impairment in HIV could depend on factors such as sex, whereas changes in PPI following METH withdrawal may depend on the quantity and duration of drug exposure.
    Behavioural pharmacology 11/2013; · 2.85 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Schizophrenia patients exhibit an exceptionally high smoking prevalence, but it is not known why, although many researchers suggest that smoking constitutes a form of self-medication. Among the schizophrenia symptoms that may be improved by nicotine are cognitive deficits. We have therefore studied the effects of long-term nicotine administration on cognition in a genetic animal model of schizophrenia susceptibility, G72-transgenic (G72Tg) mice. The effect of long-term nicotine or saline administration by osmotic minipumps on different cognitive domains was assessed in G72Tg mice and controls using a battery of behavioural tests. To investigate the mechanism underlying phenotypic differences, quantitative autoradiographic mapping of nAChR subtypes was performed in forebrain structures to explore the effect of chronic nicotine exposure on nAChR density in WT and G72Tg mice. We found a striking influence of genotype on cognitive effects of chronic nicotine administration. Whereas chronic nicotine disrupted cognitive performance in WT mice, it was effective in restoring impaired prepulse inhibition, working memory, and social recognition in G72Tg mice. However, long-term spatial learning was further impaired by nicotine in transgenic animals. In contrast, associative learning was protected by G72-expression against adverse nicotine effects, as seen in WT animals. G72-expression did not decisively influence nicotine-induced up-regulation of the α4β2(*) subtype, whereas α7 nAChR density was differentially altered by genotype or by a genotype·treatment interaction in specific brain areas, most notably hippocampal subregions. Our data support the hypothesis that nicotine self-medication of schizophrenics improves cognitive symptoms, possibly by facilitating nicotine-induced α7 nAChR activation in the hippocampus.
    British Journal of Pharmacology 01/2014; · 5.07 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In order to better understand animal models of Alzheimer's disease, novel phenotyping strategies have been established for transgenic mouse models. In line with this, the current study characterised male APPxPS1 transgenic mice on mixed C57BL/6JxC3H/HeJ background for the first time for social recognition memory, sensorimotor gating, and spatial memory using the cheeseboard test as an alternative to the Morris water maze. Furthermore, locomotion, anxiety, and fear conditioning were evaluated in transgenic and wild type-like animals. APPxPS1 males displayed task-dependent hyperlocomotion and anxiety behaviours and exhibited social recognition memory impairments compared to wild type-like littermates. Spatial learning and memory, fear conditioning, and sensorimotor gating were unaffected in APPxPS1 transgenic mice. In conclusion, this study describes for the first time social recognition memory deficits in male APPxPS1 mice and suggests that spatial learning and memory deficits reported in earlier studies are dependent on the sex and genetic background of the APPxPS1 mouse line used. Furthermore, particular test conditions of anxiety and spatial memory paradigms appear to impact on the behavioural response of this transgenic mouse model for Alzheimer's disease.
    Behavioural brain research 02/2013; · 3.22 Impact Factor

Full-text (2 Sources)

View
14 Downloads
Available from
May 23, 2014