P. Maguire, N. Tsai, J. Kamal
Mar 24, 1992
Citations
2
Influential Citations
114
Citations
Quality indicators
Journal
European Journal of Pharmacology
Abstract
Abstract Receptor binding assays using [3H]DAGO ([D-Ala2,MePhe4-Gly5]enkephalin (μ), [3H]DPDPE ([D-Pen2,D-Pen5]enkephalin (δ) and [3H]U-69593 (κ) were done in guinea pig whole brain membranes. Agonist activity was determined in norbinaltorphimine or β-funaltrexamine (β-FNA) treated guinea pig ileum (μ and κ, respectively) and β-FNA-treated mouse vas deferens (δ). The compounds with highest affinity were the most potent at the μ-receptor. The selectivity observed in the binding affinities was also found in in vitro activity. No correlation was found between μ-affinity and selectivity; the highest affinity analog, lofentanil, was found to be among the least selective, while another high affinity analog, R30490, was the most μ-selective. The results show that not all fentanyls are highly μ-selective, and could produce actions through δ- and κ-opiate receptors.