Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2008634 | Peptides | 2006 | 7 Pages |
Abstract
The partial μ-opioid receptor pool inactivation strategy in isolated mouse vas deferens was used to determine partial agonism of endomorphins and their analogs (endomorphin-1-ol, 2â²,6â²-dimethyltyrosine (Dmt)-endomorphin-1, endomorphin-2-ol and (d-Met2)-endomorphin-2) using morphine, normorphine, morphiceptin, (d-Ala2,MePhe4,Gly5-ol)-enkephalin (DAMGO) and its amide (DAMGA) as reference opioid agonists. Agonist affinities (KA) and efficacies were assessed both by the “null” and the “operational” method. The KA values determined by the two methods correlated significantly with each other and also with the displacing potencies against 3H-naloxone in the receptor binding assay in the presence of Na+. DAMGO and DAMGA were full agonist prototypes, morphine, endomorphin-1, endomorphin-1-ol, Dmt-endomorphin-1, endomorphin-2-ol and (d-Met2)-endomorphin-2 were found by both methods to be partial agonists whereas the parameters for normorphine, morphiceptin and endomorphin-2 were intermediate.
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Authors
András Z. Rónai, Mahmoud Al-Khrasani, Sándor Benyhe, Imre Lengyel, László Kocsis, György Orosz, Géza Tóth, Erzsébet Kató, László Tóthfalusi,