PITUITARY ADENYLATE-CYCLASE ACTIVATING POLYPEPTIDE (PACAP) IS A POTENT RELAXANT OF THE RAT ILEUM

Authors
KATSOULIS S CLEMENS A SCHWORER H CREUTZFELDT W SCHMIDT WE
Citation
S. Katsoulis et al., PITUITARY ADENYLATE-CYCLASE ACTIVATING POLYPEPTIDE (PACAP) IS A POTENT RELAXANT OF THE RAT ILEUM, Peptides, 14(3), 1993, pp. 587-592
Citations number
43
Categorie Soggetti
Biology
Journal title
Peptides → ACNP
ISSN journal
01969781
Volume
14
Issue
3
Year of publication
1993
Pages
587 - 592
Database
ISI
SICI code
0196-9781(1993)14:3<587:PAAP(I>2.0.ZU;2-O
Abstract
The effect and mode of action of pituitary adenylate cyclase activatin g polypeptide (PACAP) were studied in rat ileal strips. PACAP relaxed, concentration dependently, rat ileum and was 50 times more potent tha n the structurally related vasoactive intestinal polypeptide (VIP). Th e inhibitory action of PACAP was not modified by TTX, omega-conotoxin, adrenergic, or ganglionic blockade, antagonists of adrenoreceptors an d muscarinic receptors, indicating a direct myogenic effect probably t hrough specific PACAP receptors. The lack of cross-tachyphylaxis betwe en PACAP and VIP suggests that both peptides act by activation of dist inct receptors. Structure-function analysis revealed that the N-termin al region of the PACAP molecule is crucial for biological activity.