Comparative effects of chronic administration of some psychotropic drugs on rat brain cortex acetylcholinesterase activity.

The response of central cholinergic neurotransmission to the chronic administration of some psychotropic drugs to rats was investigated using brain acetylcholinesterase activity as a neurochemical marker for cholinergic neurons. Rats were divided into four groups. Three experimental groups were given chlorpromazine, amitriptyline, or diazepam respectively, for a period of 30 days; and the control group received physiological saline only. Long-term treatment of chlorpromazine and amitriptyline resulted in significant increases in rat brain cortex enzyme activity, whereas only a slight increase was observed in the diazepam-treated group. These results indicate that the chronic treatment with some psychotropic drugs causes changes in central cholinergic transmission.