Somatostatin inhibits the centrally mediated hypertensive response to clonidine in freely moving rats

Abstract

The effect of somatostatin on the hypertensive response induced by intracerebroventricular (i.c.v.) injection of clonidine was investigated in freely moving rats. A 10 micrograms i.c.v. injection of clonidine produced a marked pressor response and a decrease in heart rate. No depressor response was induced by clonidine. The i.c.v. pretreatment with somatostatin (2 and 5 micrograms) dose-dependently inhibited the pressor response to i.c.v. injected clonidine (10 micrograms), and a long-lasting depressor response was observed. Systemic (i.v.) treatment with somatostatin had no such effect. These results suggest that brain somatostatin modulates the centrally-mediated pressor response to clonidine.