Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2005-2-23
pubmed:abstractText
Tissue plasminogen activator (tPA) is the predominant plasminogen activator present in the vascular and nervous systems. Prior studies of the two have emphasized different tPA sources; respectively, endothelium and neurons. A closer relationship is now suggested by evidence that the peripheral sympathetic nervous system synthesizes and infuses enzymatically active tPA into small artery walls and the microcirculation. TPA may thus be the only known neural product able to effect degradation of the artery wall extracellular matrix. This brief review considers historical and current indications for the existence of such an autonomically controlled system and some physiologic implications. Immunohistochemical tPA expression in small arteries and arterioles is more prominent in the outer wall sympathetic axon plexus than in endothelium. Its presence in nerve filaments beneath the seldom-studied adventitia was obscured in earlier localizations. The systemic impact of a neural distribution is suggested by a 60% reduction of blood tPA activity after chemical sympathectomy. TPA-bearing axons extend outward from ganglion neuron cell bodies to reach even thin-walled vasa vasora and uveal microvessels. Ganglion cell bodies synthesize and package tPA in vesicles for the long axoplasmic transport. Densely innervated intact vessels release much greater amounts of tPA in vitro than do larger vessels, indicating a high neuron tPA production capacity and a large storage reservoir available within axon networks. The influence of an autonomically controlled plasmin production within small artery walls on regulation of blood pressure and capillary perfusion awaits further investigation. Its possible role in the pathogenesis of vessel wall matrix degradations in aging, hypertension, and diabetes may also merit further consideration.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0360-4012
pubmed:author
pubmed:copyrightInfo
Copyright 2005 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
79
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
727-33
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Distribution of sympathetic tissue plasminogen activator (tPA) to a distant microvasculature.
pubmed:affiliation
University of Connecticut Health Center, Farmington, CT 06030-3105, USA. jorourke@uchc.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Review, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural