8 research outputs found
Sex difference in up-regulation of nicotine acetylcholine receptors in rat brain
PubMed ID: 9315514This study tested for sex differences in the effects of chronic nicotine administration and withdrawal on nicotine acetylcholine receptor binding in brain. Rats received nicotine (0.6 mg/kg, sc) or saline once daily fore 15 days, and were sacrificed 1 or 20 days after termination of treatment. Saturation studies of nAChR binding were performed using [3H]cystine as the radioligand in whole brains minus cerebellum taken from animals in the chronic treatment groups and from native rats. Male but not female rats that received chronic nicotine had higher receptor densities than corresponding control groups; up-regulation of nAChR was not seen 20 days after withdrawal. Furthermore, in groups that showed no up-regulation (controls and rats withdrawn for 20 days), nAChR densities were higher in female rats than males. The findings underscore the importance of sex differences in pharmacological responses as well as in basal neurochemical parameters
Learning induces changes in the central cholinergic system of the rat in a sexually dimorphic pattern
PubMed ID: 1522028The involvement of the central cholinergic system in learning and the possible sexual dimorphism in related brain responses were investigated. Rats were exposed to different environmental conditions and to active avoidance learning. The resulting changes were studied using the following approaches: muscarinic receptor binding (MRB), acetylcholinesterase (AChE) and choline acetyltransferase (CAT) activities. The statistical evaluation of the data reveal that learning induces changes, especially in the postsynaptic component of the central cholinergic system, which shows some sexual dimorphism, and that males and females respond with different levels of increased cholinergic activity to informal and associative learning. © 1992.1987/067s studyw as supportedb y the Ege Univer-esearchF oundation Grant No: 1987/067. The authors thank Mrs. Hatice Arsoy for her excellenta ssistancein learningt rials. -
Dehydroepiandrosterone sulfate and cognitive function in the elderly: The InCHIANTI Study
DHEA and its sulfate derivative (DHEAS) decline with age. The decline in DHEAS
levels has been associated with many physiological impairments in older persons
including cognitive dysfunction. However, data regarding the possible
relationship between DHEAS and cognition are scant. We investigated whether
DHEAS levels are associated with presence and development of lower cognitive
function measured by the Mini Mental State Examination (MMSE) in older men and
women. One thousand and thirty-four residents aged > or =65 yr of the InCHIANTI
Study with data available on DHEAS and MMSE were randomly selected. MMSE was
administered at baseline and 3 yr later. Among these, 841 completed a 3-yr
follow-up. Parsimonious models obtained by backward selection from initial
fully-adjusted models were used to identify independent factors associated with
MMSE and DHEAS. The final analysis was performed in 755 participants (410 men
and 345 women) with MMSE score > or =21. A significant age-related decline of
both DHEAS levels (p<0.001) and MMSE score (p<0.001) was found over the 3-yr
follow-up. At enrolment, DHEAS was significantly and positively associated with
MMSE score, independently of age and other potential confounders (beta+/-SE
0.003+/-0.001, p<0.005). Low baseline DHEAS levels were predictive of larger
decline of MMSE and this relationship was significant after adjusting for
covariates (beta+/-SE -0.004+/-0.002, p<0.03). Our data show a significant and
positive association between DHEAS and cognitive function, assessed by MMSE
test. Low DHEAS levels predict accelerated decline in MMSE score during the 3-yr follow-up period