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The contribution of α2-adrenoceptor and opioid receptor mechanisms to antinociception differs in Lewis and Fischer 344 rats
- Source :
-
European Journal of Pharmacology . Apr2003, Vol. 465 Issue 3, p251. 6p. - Publication Year :
- 2003
-
Abstract
- Lewis and Fischer 344 (F344) rats differ in their physiological and pharmacological responses to a variety of environmental stimuli, which have been partially attributed to endogenous opioid function. Since opioid and α2-adrenoceptor mechanisms are closely related, we have comparatively examined the contribution of both systems to antinociception in female Lewis and F344 rats by the tail-flick method. Basal responses of F344 and Lewis rats were found to be similar, both showing a slight but significant increase in reaction time along the experimental period which was not completely reversed by naloxone. Morphine exhibited a bell-shaped dose–response curve in Lewis rats, these animals being more sensitive than F344 at 1 and 5 mg/kg but less sensitive at 10 mg/kg. Clonidine up to 0.1 mg/kg was more active in F344 rats. The α2-adrenoceptor antagonist yohimbine provoked a higher hyperalgesic effect in Lewis rats and decreased morphine antinociception in both strains. The existence of a balanced contribution of opioid and α2-adrenoceptor mechanisms to control pain transmission in both strains is discussed. [Copyright &y& Elsevier]
- Subjects :
- *OPIOIDS
*ENVIRONMENTAL health
Subjects
Details
- Language :
- English
- ISSN :
- 00142999
- Volume :
- 465
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- European Journal of Pharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 9447101
- Full Text :
- https://doi.org/10.1016/S0014-2999(03)01532-2