Effects of drugs on tremor and increase in brain acetylcholine produced by oxotremorine in the rat.

1. In rats the effect of drugs on oxotremorine tremor and oxotremorine-induced increase in brain acetylcholine has been investigated.2. Reserpine, (+/-)-alpha-methylmetatyrosine and diethyldithio-carbamic acid, drugs which have in common the ability to decrease tissue noradrenaline concentration, inhibited oxotremorine tremor without preventing the oxotremorine-induced increase in brain acetylcholine.3. (+/-)-p-chlorophenylalanine, a depletor of tissue 5-hydroxytryptamine, did not inhibit oxotremorine tremor.4. Phenoxybenzamine and propranolol inhibited oxotremorine tremor, and propranolol was without effect on oxotremorine-induced increase in brain acetylcholine.5. The toxicity of oxotremorine was increased by reserpine and phenoxybenzamine.6. The significance of these findings is discussed with regard to the mode of action of oxotremorine.