A comparison of the hemodynamic effects produced by electrical stimulation of subnuclei of the paraventricular nucleus.
The paraventricular nucleus of the hypothalamus (PVN) is composed of magnocellular and parvocellular subdivisions. Magnocellular neurosecretory neurons project to the neurohypophysis while parvocellular neurons send monosynaptic axonal projections to autonomic regulatory areas in the brainstem and spinal cord. In the present study, we investigated the hemodynamic effects produced by selective magnocellular or parvocellular stimulation. In urethane anesthetized rats with intact baroreflexes, magnocellular and parvocellular stimulation produced only slight differences in hemodynamic responses, however, following acute sinoaortic denervation a clear difference was observed. Parvocellular stimulation produced an increase in arterial pressure and vasoconstriction in gut, kidney and skeletal muscle. Magnocellular stimulation produced little effect on arterial pressure and marked vasodilation in the hindquarters. Blockade of peripheral vasopressin vascular receptors did not affect the vasoconstrictor response produced by stimulation of PVN. These data are consistent with the hypothesis that the long descending neural projections of the parvocellular PVN subserve a selective vasoconstrictor function.
D000818:Animals; D003714:Denervation; D004558:Electric Stimulation; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D010286:Paraventricular Hypothalamic Nucleus / Q000098:blood supply* / Q000502:physiology; D011311:Pressoreceptors / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000187:drug effects; D017483:Receptors, Vasopressin; D012018:Reflex / Q000502:physiology; D012850:Sinus of Valsalva / Q000502:physiology; D014667:Vasopressins / Q000037:antagonists & inhibitors
D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D014667:Vasopressins