The localization and release of substance P and calcitonin gene-related peptide at nerve fibre endings in rat cutaneous nerve neuroma.
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| Abstract |
This study uses radiological and immunocytochemical techniques to investigate the localization, content, transport and release of substance P- and calcitonin gene-related peptide-like immunoreactivity (SP-LI and CGRP-LI, respectively) in nerve fibre endings in 1-, 3- and 5-week-old cutaneous nerve neuromas. Neuromas were induced by ligating and transecting the saphenous nerve in anaesthetized Sprague-Dawley rats. The content of both neuropeptides in 3-week-old saphenous nerve neuroma was significantly reduced compared to that in normal saphenous nerve. At 5 weeks the levels of the peptides in the neuromas had returned to normal but remained reduced in the nerve just proximal to the neuroma. Following a 24-h ligation of the nerve proximal to 3-week-old neuromas there was a diminished immunocytochemical staining for SP-LI and CGRP-LI both proximal and distal to the ligature when compared to that seen at ligations of normal nerves. This indicates a decreased transport of the neuropeptides both to and from the 3-week-old neuromas. The density of neuropeptide staining at ligatures of nerves with 5 week or older neuromas had increased, but still remained less than that seen at ligations of normal nerve. Both a basal and a bradykinin-induced release of SP-LI and CGRP-LI from nerve fibre endings in the neuroma was demonstrated. The basal release was demonstrated by exposing the neuromas, in situ, to solutions containing 50 microM morphine plus 2 mM CoCl2 for 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)
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| Authors | D M White, J D Leah, M Zimmermann |
| Journal | Brain research (Brain Res) Vol. 503 Issue 2 Pg. 198-204 (Dec 04 1989) ISSN: 0006-8993 [Print] Netherlands |
| PMID | 2481563 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
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