Exogenous opioids influence the microcirculation of injured
peripheral nerves.
Schaafsma, Lisa, and Douglas Zochodne.
Department of Clinical Neurosciences, University of Calgary, 3330
Hospital Drive, N.W., Calgary, Alberta, T2N 4N1
APStracts 3:0276H, 1996.
Local microvessels of peripheral nerve trunks (vasa nervorum) dilate
following capsaicin-induced inflammation or local nerve trunk injury.
In previous work, we observed that morphine blocked capsaicin-induced
dilation of vasa nervorum presumably through the action of local
opioid receptors. In the present work, we studied injury-related
hyperemia of the rat sciatic vasa nervorum using laser doppler and
hydrogen clearance microelectrode measurements of local perfusion.
Systemic morphine reversed hyperemia by vasoconstricting both
extrinsic and intrinsic microvessels supplying 48 hour old 'neuroma'
preparations or crushed zones of peripheral nerve trunks. Morphine
did not constrict microvessels of contralateral uninjured or sham
exposed but uninjured sciatic nerves. In contrast to the injured
nerves, contralateral uninjured nerves exposed to morphine frequently
had a rise in local perfusion, indicating vasodilation. Morphine's
vasoconstrictive actions were blocked by pretreatment with naloxone
and were not mimicked by saline injections alone.
Received 14 August 1995; accepted in final form 13 June 1996.
APS Manuscript Number H766-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996