| Sympathetic vasoconstriction is potentiated in arteries caudal but not rostral to a spinal cord transection in rats. | |
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MedLine Citation:
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PMID: 20822463 Owner: NLM Status: In-Process |
Abstract/OtherAbstract:
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Sympathetic nerve-mediated contractions of mesenteric and tail arteries controlled by preganglionic neurones decentralized by a spinal cord injury (SCI) are potentiated, and likely contribute to autonomic dysreflexia. However, reactivity to the α(1)-adrenoceptor agonist phenylephrine has been reported to be enhanced in vascular beds controlled by preganglionic neurones lying both rostral and caudal to an SCI in vivo. Here responses of isometrically-mounted median and saphenous arteries isolated from rats 2 and 8 weeks after transection of the T4 spinal cord have been compared with those from sham-operated rats. After SCI, contractions of median arteries to perivascular nerve stimulation, to α-adrenoceptor agonists (phenylephrine and clonidine), to the P2X-purinoceptor agonist α,β-methylene ATP, and to 60 mM K(+) were unchanged. Blockade of nerve-evoked contractions by α-adrenoceptor antagonists (prazosin and idazoxan) was not affected by SCI in either the median or saphenous arteries. In contrast, at 2 and 8 weeks after SCI, nerve-evoked contractions of saphenous arteries were potentiated. Saphenous arteries were less sensitive to phenylephrine 8 weeks after SCI, and their contractions to 60 mM K(+) were reduced. However, the sensitivity of saphenous arteries to clonidine was unchanged by SCI. Eight weeks after SCI, the reactivity of saphenous arteries to α,β-methylene ATP was unchanged, but the P2-antagonist suramin produced more blockade of nerve-evoked contractions. These findings demonstrate that neurovascular transmission is enhanced in arteries located caudal, but not rostral, to a spinal transection. In the saphenous artery, the most likely explanation seems to be an increase in neurotransmitter release, as may occur in other inactive sympathetic pathways caudal to the lesion. |
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Authors:
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Nicole M Rummery; Diana Tripovic; Elspeth M McLachlan; James A Brock |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of neurotrauma Volume: 27 ISSN: 1557-9042 ISO Abbreviation: J. Neurotrauma Publication Date: 2010 Nov |
Date Detail:
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Created Date: 2010-11-22 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8811626 Medline TA: J Neurotrauma Country: United States |
Other Details:
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Languages: eng Pagination: 2077-89 Citation Subset: IM |
Affiliation:
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Spinal Injuries Research Centre, Prince of Wales Medical Research Institute, University of New South Wales, Sydney, New South Wales, Australia. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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