Vasodilatation by carbon dioxide and sodium nitroglycerin reduces compliance of the cerebral arteries in humans.

Autor: Moir ME; School of Kinesiology, University of Western Ontario, London, Ontario, Canada., Vermeulen TD; School of Kinesiology, University of Western Ontario, London, Ontario, Canada., Smith SO; School of Kinesiology, University of Western Ontario, London, Ontario, Canada., Woehrle E; School of Kinesiology, University of Western Ontario, London, Ontario, Canada., Matushewski BJ; School of Kinesiology, University of Western Ontario, London, Ontario, Canada., Zamir M; Department of Applied Mathematics, University of Western Ontario, London, Ontario, Canada.; Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada., Shoemaker JK; School of Kinesiology, University of Western Ontario, London, Ontario, Canada.; Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.
Jazyk: angličtina
Zdroj: Experimental physiology [Exp Physiol] 2021 Aug; Vol. 106 (8), pp. 1679-1688. Date of Electronic Publication: 2021 Jun 30.
DOI: 10.1113/EP089533
Abstrakt: New Findings: What is the central question of this study? Vascular compliance importantly contributes to the regulation of cerebral perfusion and complex mechanisms are known to influence compliance of a vascular bed: while vasodilatation mediates changes in vascular resistance, does it also affect compliance, particularly in the cerebral vasculature? What is the main finding and its importance? Cerebral vasodilatation, elicited by hypercapnia and sodium nitroglycerin administration, reduced cerebrovascular compliance by approximately 26% from baseline. This study provides new insight into mechanisms mediating cerebrovascular compliance.
Abstract: Changes in vascular resistance and vascular compliance contribute to the regulation of cerebral perfusion. While changes in vascular resistance are known to be mediated by vasodilatation, the mechanisms contributing to changes in vascular compliance are complex. In particular, whether vasodilatation affects compliance of the vasculature within the cranium remains unknown. Therefore, the present study examined the impact of two vasodilatation pathways on cerebrovascular compliance in humans. Fifteen young, healthy adults (26 ± 5 years, seven females) completed two protocols: (i) sublingual sodium nitroglycerin (SNG; 0.4 mg) and (ii) hypercapnia (5-6% carbon dioxide gas mixture for 4 min). Blood pressure waveforms (finger photoplethysmography) and middle cerebral artery blood velocity waveforms (transcranial Doppler ultrasound) were input into a modified Windkessel model and an index of cerebrovascular compliance (Ci) was calculated. During the SNG protocol, Ci decreased 24 ± 17% from baseline ((5.0 ± 2.3) × 10 -4  cm s -1  mmHg -1 ) to minute 10 ((3.6 ± 1.2) × 10 -4  cm s -1  mmHg -1 ; P = 0.009). During the hypercapnia protocol, Ci decreased 28 ± 9% from baseline ((4.4 ± 1.9) × 10 -4  cm s -1  mmHg -1 ) to minute 4 ((3.1 ± 1.4) × 10 -4  cm s -1  mmHg -1 ; P < 0.001). Cerebral vasodilatory stimuli induced by nitric oxide and carbon dioxide mechanisms reduced compliance of the cerebral vascular bed by approximately 26% from supine baseline values.
(© 2021 The Authors. Experimental Physiology © 2021 The Physiological Society.)
Databáze: MEDLINE
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