Renin release and water-salt balance after central serotonin depletion by p-chlorophenylalanine in Brattleboro and Wistar rats: possible role of ADH.

Plasma renin activity (PRA), plasma renin concentration (PRC) and brain serotonin content were investigated 48 h after i.p. administration of central serotonin depletor p-chlorophenylalanine (pCPA) (300 mg kg-1) in male Wistar (Wi) and diabetes insipidus Brattleboro (DI) rats. Water-salt balance and systolic blood pressure were followed up to 7th day after treatment. In addition, PRA was studied 48 h after drug administration in adrenalectomized and renal denervated Wi rats. Similar decrease of brain serotonin concentration was observed in both Wi and DI rats 48 h after pCPA treatment. PRA in Wi rats was unchanged despite the observed negative water-salt balance, decreased in adrenalectomized and renal denervated Wi rats and increased in DI rats in comparison with respective vehicle-treated controls. In WI rats PRC was not affected by pCPA but increased in DI rats. Negative water-salt balance was observed in both Wi and DI rats on the first day following treatment due to polyuria and suppressed food intake. During next following days a mild elevation of systolic blood pressure was found in both groups associated with opposite urinary responses: antidiuresis in Wi and polyuria in DI rats. The results indirectly show that pCPA-induced suppression of renal renin secretion observed in Wi rats may be due to prevailing inhibitory action of antidiuretic hormone.