Plasma protein extravasation into the rat knee joint induced by calcitonin gene-related peptide.
In previous experiments, intra-articular administration of calcitonin gene-related peptide (CGRP) failed to elicit plasma protein extravasation into synovial fluid. In the present study, using a sensitive technique to assay protein in synovial fluid, intra-articular perfusion of CGRP (10(-6) M) was found to produce protein extravasation which was sustained throughout the period of infusion. Both lower (10(-7) M) and higher (10(-5) M) concentrations of CGRP failed to produce extravasation. This failure at the highest concentration of CGRP was the likely consequence of a significant fall in arterial blood pressure which occurred with administration of CGRP at this concentration. In the presence of arterial hypotension induced by an alpha-adrenoceptor antagonist, 10(-6) M CGRP failed to produce extravasation. Plasma extravasation induced by CGRP was a specific effect and not merely a consequence of its potent vasodilator properties as similar vasodilator responses induced by a beta-adrenoceptor agonist failed to induce protein leakage. These findings indicate that CGRP can alter blood vessel permeability and therefore could additionally contribute to neurally mediated inflammatory responses.
Karimian
M
M
Institute of Physiology, University of Glasgow, UK.
Ferrell
W R
WR
D000818:Animals; D001168:Arthritis / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D001794:Blood Pressure / Q000187:drug effects; D001798:Blood Proteins / Q000378:metabolism*; D015740:Calcitonin Gene-Related Peptide / Q000008:administration & dosage / Q000494:pharmacology*; D007270:Injections, Intra-Articular; D007596:Joints / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013582:Synovial Fluid / Q000187:drug effects / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects
D001798:Blood Proteins; D015740:Calcitonin Gene-Related Peptide