AJP - Regulatory, Integrative and Comparative Physiology, Vol 264, Issue 1 143-R148, Copyright © 1993 by American Physiological Society
Suppression by central AVP of prostaglandin E1 hyperthermia in one-kidney, one-clip Goldblatt hypertensive rats
D. Fyda, W. Veale and Q. Pittman
Neuroscience Research Group, University of Calgary, Alberta, Canada.
We have investigated the ability of the one-kidney, one-clip (1K,1C)
hypertensive rat to develop a hyperthermic response to
intracerebroventricular injection of prostaglandin (PG) E1. Accordingly,
core temperature was monitored in response to PGE1 injections both
preoperatively and on days 4, 8, 12, and 18 after either unilateral
nephrectomy or the induction of hypertension due to nephrectomy plus renal
artery clipping. Temperature responses to PGE1 were similar throughout each
test day in normotensive, unilaterally nephrectomized control rats. In
contrast, 1K,1C rats became hypertensive within 4 days of renal artery
clipping, and at this time the hyperthermic response to PGE1 was virtually
abolished. A reduced hyperthermic response was also seen at 8 and 12 days
after clipping; by 18 days responses were again similar to controls. To
determine whether central arginine vasopressin (AVP) was involved in the
suppression of the hyperthermic response, we pretreated other hypertensive
rats centrally with the V1-AVP antagonist [d(CH2)5Tyr(Me)]AVP before PGE1
injection. In 1K,1C animals thus treated, temperature responses 4-12 days
after clipping were indistinguishable from those of similarly treated
normotensive control rats. We suggest that the reduced hyperthermic
responses to PGE1 seen in the 1K,1C rats during the initial development of
hypertension may be due to activation of brain AVP pathways.
