Stroke, Vol 19, 73-79, Copyright © 1988 by American Heart Association
RD Bevan, JA Bevan and JG Frazee
Diltiazem given 48 hours before experimental subarachnoid hemorrhage
protects the cerebral vasculature of monkeys against the widespread
cerebrovascular spasm seen on angiography after 5-6 days and against
associated neurologic defects. In vitro examination of the cerebral
arteries from treated monkeys shows that compared with untreated animals,
the functional changes in the vascular smooth muscle cells, the increase in
arterial wall stiffness, and the decrease in contractility, all of which
were prominent in untreated monkeys, were relatively small. Other changes
such as abnormal spontaneous myogenic tone, decreased responsiveness to
constrictor and dilator nerve activation, and other indexes of neuronal
function were little influenced by the drug. We suggest that chronic
cerebrovasospasm may be initiated by the combined action of exceptionally
high concentrations of a number of putative spasmogens causing injury to
the larger cerebral arteries. However, the later development of intractable
spasm is related to the location of blood clot and to the involvement of
the vascular wall in an inflammatory process. The combined insult results
in pathologic changes in the artery wall resulting in increased thickness
and stiffness. Diltiazem acts on cerebrovascular smooth muscle in lower
concentrations than on smooth muscle in other vascular beds, interfering
with calcium entry through receptor-operated and potential-sensitive
channels, and may protect against calcium-induced cell death through these
and additional actions. Protection against early events presumably prevents
the genesis of the subsequent chronic state.
ARTICLES
Diltiazem protects against functional changes in chronic cerebrovasospasm in monkeys
Department of Pharmacology, University of Vermont, Burlington.
This article has been cited by other articles:
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M. Zuccarello, R. Boccaletti, M. Tosun, R. M. Rapoport, and J. A. Bevan Role of Extracellular Ca2+ in Subarachnoid Hemorrhage-Induced Spasm of the Rabbit Basilar Artery Stroke, October 1, 1996; 27(10): 1896 - 1902. [Abstract] [Full Text] |
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