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Updated: Oct 3, 2026

A Method of Nodose Ganglia Injection in Sprague-Dawley Rat
Published on: November 25, 2014
Sex-related suppression of reflex jaw muscle activity by peripheral morphine but not GABA
B B Cai1, B E Cairns, B J Sessle
1Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, Ontario M5G 1G6, Canada.
Abstract:
The present study examined the effect of peripherally applied morphine and GABA on jaw muscle electromyographic activity reflexly evoked by co-injection of glutamate into the temporomandibular joint (TMJ) of lightly anesthetized Sprague-Dawley rats of both sexes. In male but not female rats, morphine significantly suppressed glutamate-evoked jaw muscle activity in a dose-dependent and naloxone-reversible manner. The median suppressive dose (+/- s.e.) for male rats was 12.7 +/- 3.1 microg (digastric muscle) and 12.6 +/- 1.3 microg (masseter muscle). GABA (5 micromol) significantly reduced glutamate-evoked muscle activity in both sexes. These data suggest that female rats are considerably less sensitive than male rats to the suppressive effects of peripherally applied morphine, but both sexes are equally affected by peripherally applied GABA.
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