EFFECT OF OXOTREMORINE ON THE APPARENT REGIONAL TURNOVER OF ACETYLCHOLINE IN MOUSE BRAIN

A calculation of the apparent turnover rate of ACh showed that oxotremorine (1 mg kg‐1) decreased the turnover in the cortex, hippocampus, midbrain.

Abstract

Abstract— The effect of oxotremorine (1 mg kg ‐1 i.p.) on the steady state concentration of acetylcholine (ACh) and choline (Ch) and the transformation of radioactive choline ([ 3 H]Ch) was studied in different brain regions of the mouse following death by microwave irradiation of the head. Oxotremorine significantly increased the concentration of endogenous ACh in the cortex and hippocampus and of endogenous Ch in the cortex. Pretreatment with atropine (5 mg kg ‐1 i.p.) prevented the increase in ACh. The biosynthesis of radioactive ACh ([ 3 H]ACh) was decreased in all brain regions. Atropine (5 mg kg ‐1 ) pretreatment counteracted this effect of oxotremorine (1 mg kg ‐1 ), while methylatropine (5 mg kg ‐1 ) had no effect except in the striatum. A calculation of the apparent turnover rate of ACh showed that oxotremorine (1 mg kg ‐1 ) decreased the turnover in the cortex, hippocampus, midbrain. and striatum.