Central choline reverses hypotension caused by alpha-adrenoceptor or ganglion blockade in rats: The role of vasopressin

Abstract

The effect of intracerebrovenricularly (i.c.v.) injected choline on blood pressure was investigated in rats made hypotensive by blocking peripheral alpha-adrenoceptors or autonomic ganglionic transmission. Choline (50-150 mu g; i.c.v.) increased blood pressure in a dose-dependent manner and 150 mu g of choline restored blood pressure to the resting level. The presser response to choline was associated with an increase in plasma vasopressin levels. Pretreatment with mecamylamine (50 mu g; i.c.v.), but not atropine (10 mu g; i.c.v.), blocked both the presser and vasopressin responses to i.c.v. choline. The vasopressin receptor antagonist, [beta-mercapto-beta,beta-cyclopenta-methylene-propionyl(1),O-Me-Try(2),Arg(8)]vasopressin (10 mu g/kg; i.v.), given 5 min after i.c.v. choline (150 mu g), abolished the presser effect of choline acid blood pressure returned to the pre-choline levels. It is concluded that the precursor of acetylcholine, choline, can increase blood pressure and reverse hypotension in alpha-adrenoceptor or ganglionic transmission blocked rats, by increasing plasma vasopressin.