Arecholine (4 milligrams), a cholinergic agonist, and choline (10 grams), a precursor of acetylcholine, significantly enhanced serial learning in normal human subjects. The subjects received methscopolamine prior to both arecholine and placebo injections. Conversely, scopolamine (0.5 milligram), a cholinergic antagonist, impaired learning and this impairment was reversed by arecholine and choline and the impairment after scopolamine were inversely proportional to the subject's performance on placebo; that is, "poor" performers were more vulnerable to both the enhancing effect of cholinergic agonist and precursor and the impairment after cholinergic antagonist than "good" performers.

No abstract

Physostigmine (an anticholinesterase agent that increases acetylcholine at the synapse), in a dose of 0.5 milligram, was given intravenously to seven normal human volunteers. When injected during rapid eye movement (REM) sleep, physostigmine woke the subjects, and when injected during non-REM sleep, it induced REM sleep. This result suggests that cholinergic mechanisms play a role in the induction of REM sleep and in modulating cortical arousal mechanisms.

No abstract