Characterization and localization of pituitary adenylate cyclase-activating polypeptide (PACAP) binding sites in the brain of the frog Rana ridibunda.
The biochemical characteristics and the distribution of pituitary adenylate cyclase-activating polypeptide (PACAP) binding sites have been investigated in the brain of the frog Rana ridibunda by using [(125)I]PACAP27 as a radioligand. Membrane-binding studies revealed the existence of high-affinity receptors for frog PACAP38 and PACAP27. In contrast, the [Des-His(1)]PACAP38 analogue had a much lower affinity and vasoactive intestinal polypeptide did not produce any displacement of the binding. Autoradiographic labeling of frozen brain sections revealed that the highest concentrations of PACAP receptors were located in the olfactory bulb, pallium, striatum, habenular nuclei, ventromedial thalamic nucleus, corpus geniculatum, posterior tubercle, dorsal part of the magnocellular preoptic nucleus, tectum, and the molecular cell layer of the cerebellum. Moderate binding was observed in the septum, in most parts of the thalamus, the dorsal hypothalamic nucleus, the median eminence, the ventral nuclei of the tegmentum, the torus semicircularis, and the interpeduncular and isthmi nuclei. The present data provide the first biochemical characterization and anatomic distribution of PACAP binding sites in the brain of a nonmammalian vertebrate species. The widespread distribution of specific PACAP receptors in the frog brain suggests that the peptide does not act solely as a hypophysiotropic factor, but likely fulfills neurotransmitter functions, neuromodulator functions, or both.
Jeandel
L
L
European Institute for Peptide Research (IFRMP 23), Laboratory of Cellular and Molecular Neuroendocrinology, INSERM U-413, UA CNRS, University of Rouen, 76821 Mont-Saint-Aignan, France.
Yon
L
L
Chartrel
N
N
Gonzalez
B
B
Fournier
A
A
Conlon
J M
JM
Vaudry
H
H
D000818:Animals; D001345:Autoradiography; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D007457:Iodine Radioisotopes; D007700:Kinetics; D008297:Male; D009479:Neuropeptides / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011895:Rana ridibunda / Q000033:anatomy & histology / Q000378:metabolism*; D051381:Rats; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone / Q000378:metabolism*
C495403:Adcyap1 protein, rat; D007457:Iodine Radioisotopes; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone