Circulatory Effects of Acute and Chronic Hypoxia.
Final rept. 8 Jan 73-31 Dec 75,
VIRGINIA COMMONWEALTH UNIV RICHMOND
Pagination or Media Count:
The aim of this work was to clarify the important mechanisms of physiological regulation of the cerebral microcirculation. The important findings of the work was as follows Effective neurogenic control and responsiveness to norepinephrine was limited to pial arteries larger than 100 microns in diameter. All vessels irrespective of size dilated markedly in response to severe elevations in arterial blood pressure exceeding 200 mmHg. This dilation at very high pressures was frequently irreversible. The vasodilation induced by arterial hypoxia was reversible by increased local supply of oxygen via perfusion of the space under the cranial window with fluorocarbon containing high concentration of oxygen, showing that the vasodilation in response to hypoxia was a local phenomenon. The changes in responsiveness due to long-term adjustments to hypercapnia and hypoxia were the result of increases in CSF bicarbonate ion concentration with hypercapnia and decreases in bicarbonate ion concentration with hypoxia.
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