| Chronic cerebral arterial spasm. The role of intracranial pressure. | |
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MedLine Citation:
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PMID: 1159478 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The author used isolated rabbit common carotid and femoral arteries perfused at a constant pressure of 90 mm Hg to examine the variation of flow (F) with transmural pressure (TMP). When the TMP was reduced below 50 to 60 mm Hg in arteries with normal smooth muscle tone, arterial resistance increased significantly causing a reduction in flow. It is suggested that the diffuse arterial narrowing that occurs in patients with severe intracranial hypertension may be the result of a similar reduction in TMP. In the presence of active vasoconstriction, any increase in extraluminal (intracranial) pressure (ICP) resulted in a substantial increase in arterial resistance and subsequent reduction of flow. This F-TMP relationship depended only on the initial degree of constriction and was independent of the vasoconstrictor used to achieve this constriction and of the artery in which this constriction was produced. A review of the literature suggests that human cerebral arteries normally exhibit only mild constrictions in response to subarachnoid blood during the chronic phase of spasm. In the present study, a mild constriction in the absence of increased ICP or a moderate increase in ICP (45 mm Hg) in the absence of constriction produced minor reductions in arterial diameter and an average flow reduction of only 5% to 10%. However, when ICP was increased to 45 mm Hg in the presence of a mild constriction, severe arterial narrowing resulted and flow was reduced by 50%. Therefore, it is suggested that chronic arterial spasm is the result of a mild constriction which is amplified by the simultaneous occurrence of increased ICP. Phenoxybenzamine was found to be effective in reversing and preventing these contractions. The improvement in flow produced by phenoxybenzamine decreased as the TMP was reduced below 60 mm Hg. The effects of both diffuse and local spasm on cerebral blood flow are discussed. |
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Authors:
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J K Farrar |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Journal of neurosurgery Volume: 43 ISSN: 0022-3085 ISO Abbreviation: J. Neurosurg. Publication Date: 1975 Oct |
Date Detail:
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Created Date: 1975-12-04 Completed Date: 1975-12-04 Revised Date: 2003-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0253357 Medline TA: J Neurosurg Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 408-17 Citation Subset: AIM; IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Cerebrovascular Circulation Chronic Disease Constriction, Pathologic / chemically induced Epinephrine / pharmacology Intracranial Pressure* Ischemic Attack, Transient / drug therapy, physiopathology* Phenoxybenzamine / pharmacology Rabbits Serotonin / pharmacology Vasomotor System / drug effects |
| Chemical | |
Reg. No./Substance:
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50-67-9/Serotonin; 51-43-4/Epinephrine; 59-96-1/Phenoxybenzamine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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