ISSN:
1432-2072
Keywords:
Antinociceptive Morphine Effect
;
6-Hydroxydopamine
;
5,6-Dihydroxytryptamine
;
Midbrain Raphe Lesion
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The antinociceptive effect of morphine was studied in rats in which degeneration of catecholamine- or serotonin-containing nerve terminals had been induced. Vocalisation during electric stimulation of the tail was used as a test for nociception. Brain catecholamines were estimated fluorimetrically. Intraventricular injection of 6-hydroxydopamine markedly reduced brain catecholamines without affecting 5-HT levels; this change was accompanied by a significant reduction of the stimulation threshold both before and after application of morphine. Intraventricular injection of 5,6-dihydroxytryptamine significantly depleted central 5-HT content; the stimulation threshold before and after morphine injection was not affected. Lesions of the midbrain raphe system induced a great reduction of forebrain 5-HT; the morphine effect was not significantly changed. The role of catecholamines and 5-HT in the antinociceptive effect of morphine is discussed in respect to these and other results recently published by this laboratory.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00419811
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