Relation of Central -Adrenoceptor and Other Receptors to the Control of Renin Secretion

¹ From the Department of Physiology, University of California, San Francisco

The location and nature of the receptors in the brain on which clonidine acts to decrease renin secretion have been investigated in dogs. Clonidine was injected into the vertebral and carotid arteries, and its effects were compared with those of norepinephrine and epinephrine when injected into the third ventricle. It was also injected intravenously (IV) after transection of the brain stem and following treatment with intraventricular 6-hydroxydopamine. The results suggest that the renin-regulating receptors are located in the brain stem in a region different from the receptors mediating the depressor response, that they are ₂-adrenoceptors, and that they are postsynaptic in location. Central ₁-adrenoceptors appear to mediate increased renin secretion. Central serotonergic receptors also mediate increased renin secretion, but it is not known how the ₁- and ₂-adrenoceptors interact with the serotonergic systems.