AJP - Regulatory, Integrative and Comparative Physiology, Vol 254, Issue 5 770-R775, Copyright © 1988 by American Physiological Society
Hemodynamic significance of the carotid rete during changes in arterial blood pressure
G. Dieguez, A. L. Garcia-Villalon, B. Gomez and S. Lluch
Departamento de Fisiologia, Facultad de Medicina, Universidad Autonoma, Madrid, Spain.
We attempted to characterize in the goat the hemodynamic response of the
carotid rete during large, passive changes in blood pressure in the
afferent limb of the rete produced by mechanical constriction of the
thoracic aorta or the inferior vena cava. Experiments in 12 anesthetized
goats demonstrated that calculated resistance through the rete decreases in
hypertension and increases in hypotension, whereas changes in resistance
through brain vessels follow opposite directions. The consequence of this
is that the carotid rete, by passively decreasing its resistance to blood
flow in hypertension, acts as a flow-facilitating system in a situation in
which smooth muscle of brain vessels contracts in response to stretch.
Contrariwise, by increasing its resistance to blood flow during systemic
hypotension, the carotid rete "limits" the passage of blood when active
relaxation of brain vessels takes place.
