AJP - Regulatory, Integrative and Comparative Physiology, Vol 269, Issue 3 497-R503, Copyright © 1995 by American Physiological Society
Fundus striati vasopressin receptors in blood pressure control
P. Kremarik, M. J. Freund-Mercier and Q. J. Pittman
Neuroscience Research Group, University of Calgary, Alberta, Canada.
Vasopressin (VP), given intracerebrally to rats, can induce antipyresis,
motor disturbances, and increases in arterial blood pressure. The
possibility that the VP-binding sites in the fundus striati (FStr) could
participate in these effects was investigated. After a bilateral injection
of 100 pmol of VP into the FStr, the fever induced by an injection of the
lipopolysaccharide of Escherichia coli (50 micrograms/kg ip) was not
affected. Bilateral injections of 100 pmol of VP did not induce motor
disturbances or alterations in body temperature after either of two
successive injections. In contrast, bilateral injections of VP into
urethan-anesthetized rats induced dose-dependent increases in arterial
pressure without affecting heart rate. This increase was blocked by a V1
antagonist; oxytocin and a V2 agonist were ineffective. In keeping with
this preliminary pharmacological analysis, radio-ligand-binding studies of
the FStr revealed binding sites in the FStr exhibiting a binding profile
typical of the V1 subtype. This study suggests that the V1 receptors in the
FStr could participate in the central regulation of the blood pressure.
