Authors: | Negus, S. S.; Pasternak, G. W.; Koob, G. F.; Weinger, M. B. |
Article Title: | Antagonist effects of β-funaltrexamine and naloxonazine on alfentanil-induced antinociception and muscle rigidity in the rat |
Abstract: | Alfentanil is a potent and short-acting mu opioid agonist that produces both antinociceptive effects and muscle rigidity. In the present study, the susceptibility of alfentanil-induced antinociception and rigidity to antagonism by the selective mu antagonist beta-funaltrexamine and the selective mu-1 antagonist naloxonazine was examined. Alfentanil (37.7-150.0 mug/kg) produced a dose-dependent increase both in antinociception as measured by the warm-water tail-dip assay and in rigidity as measured by electromyographic recording of the gastrocnemius muscle. Both beta-funaltrexamine (10.0 and 20.0 mg/kg) and naloxonazine (7.5 and 15.0 mg/kg) produced dose-dependent and parallel rightward shifts in the alfentanil dose-effect curves for both antinociception and rigidity. Furthermore. the alfentanil dose-effect curves for antinociception and rigidity were shifted to the right to a similar degree by any given pretreatment. These results suggest that alfentanil-induced antinociception in the warm-water tail-dip test and rigidity are mediated by pharmacologically similar populations of opioid receptors. More specifically, these results suggest that mu-1 opioid receptors mediate both alfentanil-induced antinociception and rigidity. |
Keywords: | morphine; analgesia; spinal-cord; involvement; agonists; opioid binding-sites; postural support mechanisms; mu-opiate receptors; brain membranes; haloperidol catalepsy |
Journal Title: | Journal of Pharmacology and Experimental Therapeutics |
Volume: | 264 |
Issue: | 2 |
ISSN: | 0022-3565 |
Publisher: | American Society for Pharmacology and Experimental Therapeutics |
Date Published: | 1993-02-01 |
Start Page: | 739 |
End Page: | 745 |
Language: | English |
ACCESSION: | WOS:A1993KM43200031 |
PROVIDER: | wos |
PUBMED: | 8437122 |
Notes: | Article -- Source: Wos |