Effects of baroreceptor activation on single unit activity of the anteroventral third ventricle region of the rat.

The anteroventral third ventricular (AV3V) region, part of the preoptic area, is involved in neurohumoral regulation of the cardiovascular system and in the development of experimental hypertension. Single unit activity within the AV3V region of the rat was recorded in response to the activation of arterial baroreceptors produced by intravenous phenylephrine or by aortic occlusion. Both inhibition and excitation of units was observed in response to an increase in arterial pressure with the highest incidence of responses in the median and periventricular subnuclei of the preoptic area. These data provide functional evidence for the neural projections from medullary baroreceptor fiber terminations to the AV3V region and preoptic area.