Journal article
Mechanisms of endotoxin-induced dilatation of cerebral arterioles
American journal of physiology. Heart and circulatory physiology, Vol.269(3), pp.H783-H788
09/01/1995
DOI: 10.1152/ajpheart.1995.269.3.H783
PMID: 7573518
Abstract
Lipopolysaccharide (LPS; endotoxin) produces dilatation of cerebral arterioles in vivo which may be due, in part, to expression of inducible nitric oxide (NO) synthase. We tested the hypothesis that aminoguanidine, an inhibitor of inducible NO synthase, would reduce endotoxin-induced dilatation of cerebral arterioles. Because mechanisms other than expression of inducible NO synthase may contribute to endotoxin-induced dilatation of cerebral arterioles, we also tested the hypothesis that calcitonin gene-related peptide (CGRP) contributes to vascular responses to endotoxin. Cerebral arteriolar diameter was measured using a closed cranial window in anesthetized rabbits under control conditions [77 +/- 3 (SE) microns] and during topical application of endotoxin (100 micrograms/ml). After 4 h, diameter of cerebral arterioles increased by 41 +/- 5%. Coapplication of aminoguanidine (0.3 mM) with endotoxin reduced vasodilatation at all time points (30 min to 4 h). Relative to control values, endotoxin treatment increased guanosine 3',5'-cyclic monophosphate (cGMP) concentration in cerebrospinal fluid (CSF) by approximately 20 fold at 4 h. Aminoguanidine attenuated the endotoxin-induced increased in CSF cGMP concentration. Aminoguanidine (0.3 mM) did not alter acetylcholine-mediated dilatation of cerebral arterioles. Coapplication of CGRP-(8-37) (0.5 microM), a specific blocker of CGRP receptors, with endotoxin significantly reduced vasodilatation in response to endotoxin at 2, 3, and 4 h. Thus 1) aminoguanidine inhibits endotoxin- but not acetylcholine-mediated dilatation of cerebral arterioles, and 2) activation of CGRP receptors mediates a portion of endotoxin-induced dilation of cerebral arterioles.
Details
- Title: Subtitle
- Mechanisms of endotoxin-induced dilatation of cerebral arterioles
- Creators
- Johnny E Brian Jr - Department of Anesthesia, University of Iowa College of Medicine, IowaCity 52242, USADonald D Heistad - Department of Anesthesia, University of Iowa College of Medicine, IowaCity 52242, USAFrank M Faraci - Department of Anesthesia, University of Iowa College of Medicine, IowaCity 52242, USA
- Resource Type
- Journal article
- Publication Details
- American journal of physiology. Heart and circulatory physiology, Vol.269(3), pp.H783-H788
- DOI
- 10.1152/ajpheart.1995.269.3.H783
- PMID
- 7573518
- ISSN
- 0363-6135
- eISSN
- 1522-1539
- Language
- English
- Date published
- 09/01/1995
- Academic Unit
- Cardiovascular Medicine; Neuroscience and Pharmacology; Internal Medicine
- Record Identifier
- 9984040307202771
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