Difference in choline acetyltransferase but similarities in catecholamine biosynthetic enzymes in brains of two rat strains differing in their response to stress.

ABSTRACT

Rats of the Wistar-Kyoto (WKY) strain are more reactive to stress than Brown-Norway (BN) rats as adjudged by their behavioral and plasma catecholamine (CA) responses to stress. Contrary to the strain differences existing in the periphery, brain CA and their biosynthetic enzyme activities were found to be similar in both strains before and after immobilization stress. However, as in the periphery, choline acetyltransferase (CAT) activity was higher in brains of WKY rats. The results suggest that (1) peripheral and central CA systems may be under different genetic control mechanisms, and (2) strain differences in CAT activity may reflect differences in cholinergic systems both in the brain and periphery, which may be important in the behavioral differences observed.