Characterization of vasoactive intestinal peptide/pituitary adenylate cyclase-activating polypeptide receptors in chick cerebral cortex.
In this study receptors for vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) were characterized in chick cerebral cortex by an in vitro binding technique, using 125I-labeled VIP ([125I]-VIP) as a ligand. The specific binding of [125I]-VIP to chick cerebral cortical membranes was found to be rapid, stable, saturable, reversible, and of high affinity. Saturation analysis resulted in a linear Scatchard plot, suggesting binding to a single class of receptor binding sites with high affinity (Kd = 0.21 nM) and low capacity (Bmax = 19.5 fmol/mg protein). The relative rank order of potency of the tested peptides to inhibit [125I]-VIP binding to chick cerebrum was VIP (chicken) > or = VIP (mammalian) > or = PACAP27 > or = PACAP38 >> VIP6-28 (mammalian) > PHI (porcine) >> neurotensin6-11-chicken VIP7-28 > neurotensin6-11-mammalian VIP7-28 >>> VIP16-28 (chicken; inactive) approximately secretin (inactive). About 60% of [125I]-VIP-binding sites in chick cerebral cortex were sensitive to Gpp(NH)p, a nonhydrolyzable analog of GTP. It has been concluded that the cerebral cortex of chick, in addition to PAC1 receptors, contains a population of VPAC-type receptors.
Zawilska
Jolanta B
JB
Department of Biogenic Amines, Polish Academy of Sciences, P-225, 90-950 Lodz, Poland. jolantaz@amina1.zabpan.lodz.pl
Niewiadomski
Pawel
P
Nowak
Jerzy Z
JZ
D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects / Q000502:physiology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D002645:Chickens / Q000378:metabolism*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D007457:Iodine Radioisotopes; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011869:Radioligand Assay; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone / Q000187:drug effects / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide / Q000187:drug effects / Q000378:metabolism*; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D013347:Subcellular Fractions; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D007457:Iodine Radioisotopes; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D006165:Guanylyl Imidodiphosphate; D014660:Vasoactive Intestinal Peptide