PT - JOURNAL ARTICLE AU - Kelly A. Berg AU - Matthew P. Rowan AU - Achla Gupta AU - Teresa A. Sanchez AU - Michelle Silva AU - Ivone Gomes AU - Blaine A. McGuire AU - Philip S. Portoghese AU - Kenneth M. Hargreaves AU - Lakshmi A. Devi AU - William P. Clarke TI - Allosteric Interactions between δ and κ Opioid Receptors in Peripheral Sensory Neurons AID - 10.1124/mol.111.072702 DP - 2012 Feb 01 TA - Molecular Pharmacology PG - 264--272 VI - 81 IP - 2 4099 - http://molpharm.aspetjournals.org/content/81/2/264.short 4100 - http://molpharm.aspetjournals.org/content/81/2/264.full SO - Mol Pharmacol2012 Feb 01; 81 AB - The peripheral δ opioid receptor (DOR) is an attractive target for analgesic drug development. There is evidence that DOR can form heteromers with the κ-opioid receptor (KOR). As drug targets, heteromeric receptors offer an additional level of selectivity and, because of allosteric interactions between protomers, functionality. Here we report that selective KOR antagonists differentially altered the potency and/or efficacy of DOR agonists in primary cultures of adult rat peripheral sensory neurons and in a rat behavioral model of thermal allodynia. In vitro, the KOR antagonist nor-binaltorphimine (nor-BNI) enhanced the potency of [d-Pen2,5]-enkephalin (DPDPE), decreased the potency of [d-Ala2,d-Leu5]-enkephalin (DADLE), and decreased the potency and efficacy of 4-[(R)-[(2S,5R)-4-allyl-2,5-dimethylpiperazin-1-yl](3-methoxyphenyl)methyl]-N,N-diethylbenzamide (SNC80) to inhibit prostaglandin E2 (PGE2)-stimulated adenylyl cyclase activity. In vivo, nor-BNI enhanced the effect of DPDPE and decreased the effect of SNC80 to inhibit PGE2-stimulated thermal allodynia. In contrast to nor-BNI, the KOR antagonist 5′-guanidinonaltrindole (5′-GNTI) reduced the response of DPDPE both in cultured neurons and in vivo. Evidence for DOR-KOR heteromers in peripheral sensory neurons included coimmunoprecipitation of DOR with KOR, a DOR-KOR heteromer selective antibody augmented the antinociceptive effect of DPDPE in vivo, and the DOR-KOR heteromer agonist 6′-GNTI inhibited adenylyl cyclase activity in vitro as well as PGE2-stimulated thermal allodynia in vivo. Taken together, these data suggest that DOR-KOR heteromers exist in rat primary sensory neurons and that KOR antagonists can act as modulators of DOR agonist responses most likely through allosteric interactions between the protomers of the DOR-KOR heteromer.