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The novel VIP-like hypothalamic polypeptide PACAP interacts with high affinity receptors in the human neuroblastoma cell line NB-OK

Journal Article · · Peptides (Fayetteville, New York); (USA)

We investigated the ability of two forms of Pituitary Adenylate Cyclase Activating Polypeptide (PACAP-38, the 38 amino acid peptide isolated from ovine hypothalamus, and PACAP-27, a shorter N-terminal (1-27) amidated version) to interact with specific receptors in membranes from the human neuroblastoma cell line NB-OK. ({sup 125}I)PACAP-27 bound rapidly and specifically to one class of high affinity sites (Kd 0.5 nM). VIP inhibited ({sup 125}I)PACAP-27 binding 300- to 1000-fold less potently than PACAP-27 and PACAP-38. One microM PHI prevented tracer binding only partially and secretin, glucagon and GRF(1-29)NH2 were ineffective in this respect. PACAP-27 and PACAP-38 stimulated adenylate cyclase activity dose dependently and with similar efficacy (Kact 0.2-0.3 nM), this activation being compatible with the occupancy of specific high affinity PACAP receptor. VIP was markedly less potent and less efficient on this enzyme than PACAP. Chemical cross-linking of ({sup 125}I)PACAP-27 followed by SDS-PAGE and autoradiography revealed specific cross-linking with a 68 kDa protein.

OSTI ID:
6324766
Journal Information:
Peptides (Fayetteville, New York); (USA), Journal Name: Peptides (Fayetteville, New York); (USA) Vol. 11:4; ISSN PPTDD; ISSN 0196-9781
Country of Publication:
United States
Language:
English