Endocrinology 2000 Feb 01;1412:657-65.

Characterization and messenger ribonucleic acid distribution of a cloned pituitary adenylate cyclase-activating polypeptide type I receptor in the frog Xenopus laevis brain.

???displayArticle.abstract???
Pituitary adenylate cyclase-activating polypeptide (PACAP) has been found to modulate neuroendocrine functions in the frog brain and pituitary, but the nucleotide sequence and brain distribution of messenger RNA (mRNA) for the selective type I receptor for PACAP (PAC1) in the frog are still unknown. Here, we report the isolation and characterization of a PAC1 receptor complementary DNA (cDNA) clone from a frog (Xenopus laevis) tadpole brain cDNA library. This cDNA encoded a 466-amino acid protein that has 74% homology with human PAC1 receptor and 48% homology to the frog vasoactive intestinal peptide/PACAP receptor. Injection of in vitro synthesized mRNA of the cloned cDNA into Xenopus oocytes resulted in expression of selective high affinity PACAP receptors (Kd = 47 pM). IC50 values for PACAP-38, PACAP-27, and VIP were 27 pM, 110 pM and >1 microM, respectively. These results indicated that the cloned cDNA represents a Xenopus PACAP-preferring PAC1 receptor. Northern hybridization revealed that PAC1 receptor mRNA was present at high levels in the brain. In situ hybridization showed that the PAC1 receptor gene was expressed highly in the pallium, preoptic nucleus, and nucleus of cerebellum, and moderately in the Purkinje cell layer of the cerebellum. Moderate PAC1 receptor mRNA signals were detected in the distal lobe of the pituitary. A knowledge of the molecular structure and expression pattern of the PAC1 receptor will facilitate further investigation of the physiological roles of PAC1 receptor in the frog brain.

???displayArticle.pubmedLink??? 10650947
???displayArticle.link??? Endocrinology
???displayArticle.grants??? [+]

Species referenced: Xenopus laevis
Genes referenced: adcyap1 adcyap1r1 klf6 vip