AJP - Heart and Circulatory Physiology, Vol 247, Issue 1 139-H145, Copyright © 1984 by American Physiological Society
Vasomotor projections from the anteroventral third ventricle (AV3V) region
M. M. Knuepfer, A. K. Johnson and M. J. Brody
The anteroventral third ventricle (AV3V) region is necessary for the
development of a variety of models of experimental hypertension.
Neuroanatomic studies have identified descending projections from this
region to the mesencephalic central gray and tegmentum. This study was done
to identify functionally the projections involved in cardiovascular
regulation from the AV3V region to the mesencephalon. Regional hemodynamic
responses to electrical stimulation of the AV3V region were compared with
responses to stimulation of the rostral central gray, and these responses
were compared before and after ablation of mesencephalic tissue.
Stimulation of the AV3V region elicited hindquarter, vasodilation and renal
and mesenteric vasoconstriction associated with a depressor response and
bradycardia. These responses were partially dependent on adrenal
catecholamines since adrenalectomy reduced hindquarter, mesenteric, and
depressor responses. Regional hemodynamic responses to central gray
stimulation were qualitatively similar and also demonstrated a partial
dependence on adrenal catecholamines. After electrolyte ablation of central
gray tissue, significant reductions in hindquarter, mesenteric, and
depressor responses to AV3V stimulation were observed. These observations
suggest that a cardiovascular control system important for the development
of several models of hypertension may be dependent on neuronal projections
from the rostral medial hypothalamus through the mesencephalic central
gray.
