[The role of brain cholinergic system in renal sodium, potassium and water excretion in rats].

In anesthetized rats intracerebroventricular (i. c. v.) injection of cholinergic agonist carbachol induced significant natriuresis, kaliuresis and diuresis (P < 0.05). Among them, the degree of natriuresis was changed with carbachol in a dose-dependent manner (r = 0.9997, P < 0.05). These responses were completely blocked by cholinergic M receptor antagonist atropine or N receptor antagonist hexamethonium pretreatment. Such effects of carbachol were inhibited in part by pretreatment with adrenergic alpha receptor antagonist phentolamine. These results indicate that the natriuresis, kaliuresis and diuresis induced by i. c. v. injection of carbachol were primarily mediated by both muscarinic and nicotinic receptors in the brain, while the effect was in part mediated secondarily via adrenergic alpha receptor.