1. Dimeric Dermorphin Analogues as µ-Receptor Probes on Rat Brain Membranes
- Author
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Lazarus, L H, Guglietta, A, Wilson, W E, Irons, B J, and de Castiglione, R
- Abstract
The opioid receptor preference for dermorphin and several dimerized structural analogues was investigated using rat brain synaptosomes and correlated with the potencies of intracerebroventricularly administered dimeric dermorphin peptides to inhibit gastric acid secretion. The carboxyl terminus of dermorphin or amino-terminal dermorphin analogues was bridged by dihydrazide or (poly)ethylenediamine structures. Synaptosomal membranes were prepared for radioligand binding assay in the presence of soybean trypsin inhibitor and preincubated to remove endogenously bound opioid peptides before storage at −70 °C. Specific radiolabeled agonists used in the radioligand binding assays were [D-Ala2,AT-methyl-Phe4,Gly-ol5][3H] enkephalin for µ-receptors and [D-Ala2,d-Leu5][3H]enkephalin for δ-receptors. δ-Receptor binding assays were conducted in the presence of 2.6 µM[N-Me-Phe3, D-Pro4]morphiceptin to suppress peptide binding to µ-receptors. [D-Ala2, N-methyl-Phe4,Gly-ol5]enkephalin and dermorphin had affinities of 1.39 and 1.22 nMfor receptors and 355.8 and 178.6 nMfor δ-receptors, respectively.
- Published
- 1989
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