Experimental catalepsy: influences of cholinergic transmission in restraint-induced catalepsy.

Possible cholinergic mechanisms in experimental catalepsy were evaluated by using the 'pinch-induced' model in mice. In control, saline-injected mice, the median number of attempts needed to achieve a criterion level of catalepsy was 6. All 3 dose levels of physostigmine reduced this median to about 2 trials; neostigmine did not significantly reduce the number of trials. Opposite effects were obtained with atropine, with which all 3 doses tested increased the number of trials needed to cause catalepsy, and at the higher doses (5 and 10 mg/kg) most of the mice (80%) became insusceptible: atropine methyl bromide had no such effects. Thus, this kind of catalepsy may be mediated by cholinergic mechanisms that are central and not peripheral.