Abstract
The fumaramate methyl ester derivatives of naltrexone (β-FNA) and oxymorphone (β-FOA) were both found to be reversible agonists on the guinea pig ileal longitudinal muscle preparation. In addition, β-FNA possessed an irreversible antagonistic effect against morphine whereas β-FOA had no such capacity. Analysis by pA2 values revealed that β-FOa resembled pure agonists like morphine and enkephalin while β-FNA resembled the mixed agonist-antagonists like nalorphine and pentazocine. The antagonism by β-FNA was very selective in that it antagonized pure agonists but had little or no effect on the effects of either mixed agonists, ethylketocyclazocine or other non-opiate-type agonists like norepinephrine.
Original language | English (US) |
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Pages (from-to) | 445-451 |
Number of pages | 7 |
Journal | European Journal of Pharmacology |
Volume | 70 |
Issue number | 4 |
DOIs | |
State | Published - Apr 9 1981 |
Keywords
- Agonist
- Antagonist
- Fumaramate methyl ester derivative
- Guinea pig ileum
- Naltrexone
- Narcotic
- Opioid receptor
- Oxymophone