AJP - Regulatory, Integrative and Comparative Physiology, Vol 245, Issue 2 281-R286, Copyright © 1983 by American Physiological Society
Hemodynamic responses to amygdaloid stimulation in spontaneously hypertensive rats
T. M. Galeno and M. J. Brody
Our studies were done to determine 1) the regional hemodynamic effects of
stimulating the central amygdaloid nucleus in conscious and anesthetized
rats and 2) whether these effects differ between normotensive Wistar-Kyoto
(WKY) and spontaneously hypertensive rats (SHR). Flow was recorded with
miniaturized pulsed Doppler probes placed on the renal and superior
mesenteric arteries and the lower abdominal aorta. In rats anesthetized
with Dialurethane, electrical stimulation elicited a depressor response
accompanied by a decrease in hindquarter vascular resistance, with little
or no change in heart rate or renal or mesenteric resistance in both SHR
and WKY. By contrast, in conscious rats, stimulation was accompanied by a
pressor response, tachycardia, and renal and mesenteric vasoconstriction in
both groups. Hindquarter vascular resistance was unchanged in WKY and
decreased at higher frequencies in SHR. There were no significant
differences between SHR and WKY, whether anesthetized or awake, in
hemodynamic responses to amygdaloid stimulation. Despite previous evidence
indicating that the central amygdaloid nucleus contributes to the
development of spontaneous hypertension, our results show that stimulation
of this region does not elicit exaggerated cardiovascular responses in SHR.
