Pharmacological δ1-and δ2-opioid receptor subtypes in the human neuroblastoma cell line SK-N-BE:: No evidence for distinct molecular entities
Pharmacological δ1-and δ2-opioid receptor subtypes in the human neuroblastoma cell line SK-N-BE:: No evidence for distinct molecular entities
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DOI：
10.1016/s0006-2952(99)00404-9
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发表时间：
2000-04-15
影响因子：
5.8
通讯作者：
Polastron, J
中科院分区：
文献类型：
--
作者：
Allouche, S;Hasbi, A;Polastron, J
The two pharmacological delta opioid receptor subtypes, delta 1 and delta 2, have been defined on the basis of pharmacological tools but remain to be characterized at the molecular level, since only a single cDNA has been cloned. The present study aimed to investigate the pharmacological properties of delta 1- and delta 2-opioid subtypes expressed in the human neuroblastoma cell line SK-N-BE and to characterize their putative corresponding mRNAs. Binding experiments using "selective" delta 1- and delta 2-opioid agonists and antagonists revealed the presence of two binding sites, demonstrating the presence of these delta 1 opioid subtypes as they were previously described. The activation of these pharmacological subtypes by the selective agonists induced the incorporation of [alpha-P-32]azidoanilide-GTP into G alpha(12)/G alpha(0) subunits with the same efficiency and potency and inhibited adenosine 3',5' cyclic monophosphate (cAMP) accumulation with similar efficiency, while their sustained activation for 15 min induced a cross-desensitization. The "selective" delta 1 and delta 2 antagonists, 7-benzylidenenaltrexone and naltrindole benzofuran, respectively, were found to be as potent in blocking the inhibition of cAMP accumulation induced by both [D-Pen(2,5)]enkephalin and Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH2,. The possibility that delta-opioid subtypes could arise from alternative splicing was ruled out by reverse transcription-polymerase chain reaction (RT-PCR) experiments and the sequencing of PCR products, which revealed the presence of a single transcript encoding for the delta-opioid receptor. Different possibilities which could account for the delta-opioid receptor heterogeneity observed in the SN-N-BE cell line are discussed. (C) 2000 Elsevier Science Inc.
