Autoregulation of blood flow during sympathetic nerve stimulation in the arteriolar network on cat sartorius muscle.
type: CreativeWork
description: Autoregulation is the tendency for blood flow to remain constant despite a change in arterial perfusion pressure. Flow regulation is achieved by adjustment of arteriolar caliber to the pressure change. The responses of arterioles are most commonly explained by either the metabolic or myogenic hypothesis. According to the metabolic hypothesis, the initial decrease in blood flow that accompanies a reduction in arterial pressure would reduce oxygen delivery and decrease tissue oxygen tension. We reasoned that the contribution of this mechanism to autoregulation of flow would be increased during sympathetic nerve stimulation because the latter causes arteriolar constriction and decreases tissue oxygen tension. However, the elevated vascular tone might also influence the myogenic response (i.e., arteriolar constriction to elevated intravascular pressure). In these experiments, we examined flow and diameter changes in arterioles of the exteriorized cat sartorius muscle during sympathetic nerve stimulation and tested the contribution of both metabolic and myogenic factors. Without sympathetic nerve stimulation, autoregulation was weak, flow fell coincident with reduced perfusion pressure. Sympathetic nerve stimulation caused significant constriction of arterioles, enhancing autoregulation, and increasing flow about 20% to 60% during perfusion pressure reduction from 110 to 80, 60, and 40 mmHg. With sympathetic nerve stimulation, arteriolar dilation to arterial pressure reduction was enhanced. This enhanced dilation was not abolished by 20% oxygen in a suffusate over the muscle, suggesting that it was not due to an enhanced metabolic response. On the other hand, arteriolar constriction to venous pressure elevation (which raises arteriolar intravascular pressure), was increased during sympathetic nerve stimulation, indicating an enhanced myogenic response. Arteriolar dilation to pressure reduction was also enhanced during norepinephrine infusion, showing that prejunctional i…
abstract: Autoregulation is the tendency for blood flow to remain constant despite a change in arterial perfusion pressure. Flow regulation is achieved by adjustment of arteriolar caliber to the pressure change. The responses of arterioles are most commonly explained by either the metabolic or myogenic hypothesis. According to the metabolic hypothesis, the initial decrease in blood flow that accompanies a reduction in arterial pressure would reduce oxygen delivery and decrease tissue oxygen tension. We reasoned that the contribution of this mechanism to autoregulation of flow would be increased during sympathetic nerve stimulation because the latter causes arteriolar constriction and decreases tissue oxygen tension. However, the elevated vascular tone might also influence the myogenic response (i.e., arteriolar constriction to elevated intravascular pressure). In these experiments, we examined flow and diameter changes in arterioles of the exteriorized cat sartorius muscle during sympathetic nerve stimulation and tested the contribution of both metabolic and myogenic factors. Without sympathetic nerve stimulation, autoregulation was weak, flow fell coincident with reduced perfusion pressure. Sympathetic nerve stimulation caused significant constriction of arterioles, enhancing autoregulation, and increasing flow about 20% to 60% during perfusion pressure reduction from 110 to 80, 60, and 40 mmHg. With sympathetic nerve stimulation, arteriolar dilation to arterial pressure reduction was enhanced. This enhanced dilation was not abolished by 20% oxygen in a suffusate over the muscle, suggesting that it was not due to an enhanced metabolic response. On the other hand, arteriolar constriction to venous pressure elevation (which raises arteriolar intravascular pressure), was increased during sympathetic nerve stimulation, indicating an enhanced myogenic response. Arteriolar dilation to pressure reduction was also enhanced during norepinephrine infusion, showing that prejunctional i…
author: Ping, Peipei.
language: en
keywords: Biology
date published: 1990
date modified: 2026-07-24T00:55:23Z
provider: University of Arizona
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Arizona.

PropertyValue
property ID: Handle
value: http://hdl.handle.net/10150/185318