THE VIP(2) RECEPTOR - MOLECULAR CHARACTERIZATION OF A CDNA-ENCODING ANOVEL RECEPTOR FOR VASOACTIVE-INTESTINAL-PEPTIDE

We have cloned and sequenced a cDNA (RPR4) encoding a new member of th e secretin/calcitonin/parathyroid hormone (PTH) receptor family. RPR4 was identified by PCR of rat pituitary cDNA, and a full-length clone w as isolated from a rat olfactory bulb cDNA library. When RPR4 was func tionally expressed in COS 7 cells, cyclic adenosine monophosphate (cAM P) production was stimulated by vasoactive intestinal peptide (VIP), p ituitary adenylate cyclase activating peptides (PACAP-38 and PACAP-27) and helodermin, with equal potency. Peptide histidine isoleucine (PHI ) and rat growth hormone releasing hormone (rGHRH) also stimulated cAM P production at lower potency. This suggests that RPR4 encodes a novel VIP receptor which we have designated the VIP2 receptor. In situ hybr idisation showed that mRNA for this receptor was present mainly in the thalamus, hippocampus and in the suprachiasmatic nucleus.