Antagonist effects of β-funaltrexamine and naloxonazine on alfentanil-induced antinociception and muscle rigidity in the rat Journal Article
| 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 |
