Author(s): Allouche S, Roussel M, Marie N, Jauzac P
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Abstract The efficacy of different opioid agonists to induce acute desensitization of the human delta-opioid receptor-mediated inhibition of cAMP accumulation was investigated in the neuroblastoma cell line SK-N-BE, which endogenously expresses these receptors. While etorphine, a non-selective alkaloid agonist, caused 50\% desensitization after a 30-min incubation, the same treatment in the presence of the selective peptide agonists, DPDPE ([D-Pen2,D-Pen5]enkephalin) and deltorphin I (Tyr-D-Ala-Phe-Asp-Val-Val-Gly), almost totally desensitized the delta-opioid receptor-mediated inhibition of adenylyl cyclase. When SK-N-BE cells were prechallenged either with alkaloid or peptide agonist, we observed a cross-desensitization that was less marked when cells were pretreated with peptide agonists and then challenged with etorphine. Taken together, these results demonstrate that human delta-opioid receptors are differentially desensitized by alkaloid and peptide agonists.
This article was published in Eur J Pharmacol
and referenced in Neurochemistry & Neuropharmacology