Cholinergic muscarinic receptors in rat cerebral cortex, basal ganglia and cerebellum undergo rapid and reversible changes after acute stress.

Rats, submitted to forced swimming for a period of 15 min (stress), were killed immediately, 60 min or 24 h thereafter. There was an initial decrease in [3H]quinuclidinyl benzilate specific binding in membranes of cerebral cortex (-27%) that returned to normal levels after 60 min. In basal ganglia (striatum and globus pallidus) there was a significant decrease (-14%) in Bmax after 60 min that recovered at 24 h. In cerebellum, an increase in [3H]quinuclidinyl benzilate binding occurred at 60 min (+41%) which was reversed at 24 h. In all cases there were no changes in affinity. These results are discussed in relation to the possible mechanisms that could be involved in the rapid, reversible and selective changes of cholinergic muscarinic receptors in response to acute stress.