This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Pearce, W. J. Articles by D'Alecy, L. G. Search for Related Content PubMed PubMed Citation Articles by Pearce, W. J. Articles by D'Alecy, L. G.

Stroke, Vol 11, 190-197, Copyright © 1980 by American Heart Association

ARTICLES

Hemorrhage-induced cerebral vasoconstriction in dogs

WJ Pearce and LG D'Alecy

Cerebrovascular responses to a 20% volume hemorrhage were studied in chloralose-anesthetized dogs with the Doppler cerebral venous outflow method. Arterial PCO2, PO2, and pH were held constant by servocontrol of ventilation. The experimental results were divided into 2 groups as determined by the spontaneous responses of mean arterial pressure (MAP) to hemorrhage. In Group 1 (n = 11), steady state MAP decreased 25%, cerebral blood flow (CBF) decreased 15%, and cerebrovascular resistance (CVR) decreased 13% (autoregulatory vasodilatation). In group 2 (n = 23), MAP changed less than 10 mm Hg, CBF decreased 13%, and CVR increased 15%. The hemorrhage-induced cerebral vasoconstriction in Group 2 was characterized by the following: phenoxybenzamine (2 mg/kg i.v., n = 3) reduced post-hemorrhage CVR from 116% to 95% of prehemorrhage CVR (cCVR); phentolamine (2 mg/kg i.v., n = 5) reduced post-hemorrhage CVR from 114% to 91% of cCVR; and verified local anesthetization of both superior cervical ganglia (n = 5) reduced post- hemorrhage CVR from 116% to 94% of cCVR. Thus in Group 2, sympathetic vasoconstriction contributed approximately 5% of cCVR; following normotensive hemorrhage, it accounted for up to 20% of post-hemorrhage CVR. In combination with prevous studies, these data suggest that cerebrovascular responses to hemorrhage balance between autoregulatory vasodilatation and sympathetic vasoconstriction.

This article has been cited by other articles:

				S. Ogoh, R. M. Brothers, W. L. Eubank, and P. B. Raven Autonomic Neural Control of the Cerebral Vasculature: Acute Hypotension Stroke, July 1, 2008; 39(7): 1979 - 1987. [Abstract] [Full Text] [PDF]

				S. Ogoh, J. P. Fisher, S. Purkayastha, E. A. Dawson, P. J. Fadel, M. J. White, R. Zhang, N. H. Secher, and P. B. Raven Regulation of middle cerebral artery blood velocity during recovery from dynamic exercise in humans J Appl Physiol, February 1, 2007; 102(2): 713 - 721. [Abstract] [Full Text] [PDF]

				S. Ogoh, R. M. Brothers, Q. Barnes, W. L. Eubank, M. N. Hawkins, S. Purkayastha, A. O-Yurvati, and P. B. Raven The effect of changes in cardiac output on middle cerebral artery mean blood velocity at rest and during exercise J. Physiol., December 1, 2005; 569(2): 697 - 704. [Abstract] [Full Text] [PDF]