TY - JOUR
T1 - Cardiovascular effects of posterior hypothalamic stimulation in baroreflex-denervated rats
AU - Barron, K. W.
AU - Heesch, C. M.
PY - 1990
Y1 - 1990
N2 - The overall purpose of this study was to examine the effect of sinoaortic baroreceptor denervation (SAD) on the cardiovascular and sympathetic outflow responses to electrical stimulation of the posterior hypothalamus. In anesthetized rats that had undergone SAD 7-10 days before experimentation, electrical stimulation of the posterior hypothalamus elicited greater increases in mean arterial pressure, iliac vascular resistance, mesenteric vascular resistance, and lumbar sympathetic nerve activity than in sham-operated baroreceptor-intact animals. Similarly, the pressor effects of intravenous norepinephrine were also augmented in the baroreceptor-denervated group compared with the baroreceptor-intact group. When posterior hypothalamic and intravenous norepinephrine pressor stimuli, which produced equivalent pressor responses in sham-operated baroreceptor-intact animals, were compared in baroreceptor-denervated animals, the pressor effects of the central hypothalamic stimulus were enhanced to a greater degree than the norepinephrine pressor effects. These data provide evidence that arterial baroreceptor reflexes exert greater buffering of pressor stimuli initiated from the central nervous system compared with pressor responses due to peripheral vascular vasoconstrictor agents.
AB - The overall purpose of this study was to examine the effect of sinoaortic baroreceptor denervation (SAD) on the cardiovascular and sympathetic outflow responses to electrical stimulation of the posterior hypothalamus. In anesthetized rats that had undergone SAD 7-10 days before experimentation, electrical stimulation of the posterior hypothalamus elicited greater increases in mean arterial pressure, iliac vascular resistance, mesenteric vascular resistance, and lumbar sympathetic nerve activity than in sham-operated baroreceptor-intact animals. Similarly, the pressor effects of intravenous norepinephrine were also augmented in the baroreceptor-denervated group compared with the baroreceptor-intact group. When posterior hypothalamic and intravenous norepinephrine pressor stimuli, which produced equivalent pressor responses in sham-operated baroreceptor-intact animals, were compared in baroreceptor-denervated animals, the pressor effects of the central hypothalamic stimulus were enhanced to a greater degree than the norepinephrine pressor effects. These data provide evidence that arterial baroreceptor reflexes exert greater buffering of pressor stimuli initiated from the central nervous system compared with pressor responses due to peripheral vascular vasoconstrictor agents.
KW - arterial baroreceptor reflex
KW - arterial blood pressure
KW - heart rate
KW - iliac blood flow
KW - lumbar sympathetic nerve activity
KW - mesenteric blood flow
KW - sinoaortic baroreceptor denervation
UR - http://www.scopus.com/inward/record.url?scp=0025042325&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.1990.259.3.h720
DO - 10.1152/ajpheart.1990.259.3.h720
M3 - Article
C2 - 2396685
AN - SCOPUS:0025042325
SN - 0363-6135
VL - 259
SP - H720-H727
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 3 28-3
ER -