Cardiovascular responses of sinoaortic-denervated rats to intra-cerebroventricular injection of alpha sub(1)- and alpha sub(2)-adrenoceptor agonists

The aim of the present work was to analyze the cardiovascular responses induced by i.c.v. administration of the alpha sub(1)- and alpha sub(2)-adrenoceptor agonists, phenylephrine and clonidine, respectively, in conscious normal and sinoaortic-denervated rats. Our findings suggest that arterial baroreceptor reflexes can modify the effects of alpha -agonists initiated in the central nervous system. Sinoaortic denervation preparations enable one to unmask the depressor response to clonidine and also demonstrate the true magnitude of the phenylephrine response.