title: cAMP produced by pituitary adenylate cyclase-activating polypeptide 27 inhibits atrial natriuretic peptide secretion in rabbit beating atria.
abstract: The aim of the present study was to determine the effects of increased cAMP levels in response to pituitary adenylate cyclase-activating polypeptide 27 (PACAP27) on atrial atrial natriuretic peptide (ANP) secretion in rabbit atria. A perfused beating atrial model was used in the present study and cAMP efflux and ANP levels in atrial perfusates were measured by radioimmnoassay. At 100 nmol/L, PACAP27 increased cAMP production, which resulted in subsequent inhibition of ANP secretion. Nicardipine (1.0 micromol/L), an L-type Ca2+ channel blocker, attenuated inhibition of ANP secretion by PACAP27. Staurosporine (1.0 micromol/L), a non-specific protein kinase inhibitor, and H-89 (1.0 micromol/L), a cAMP-dependent protein kinase A (PKA) inhibitor, completely blocked the inhibition of ANP secretion in response to PACAP27 but had no effect on PACAP27-induced increases in cAMP. In conclusion, the results suggest that increased cAMP levels in response to PACAP27 negatively regulate ANP secretion via the adenylate cyclase-cAMP-PKA signalling pathway in rabbit atria and that L-type Ca2+ channels may be involved, in part, in the regulation of ANP secretion by cAMP.
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Yanbian University, Yanji, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Liu
authors.forename: Zhe-Long
authors.initials: ZL
authors.lastname: Liang
authors.forename: Xiang-Lan
authors.initials: XL
authors.lastname: Li
authors.forename: Yuan-Zhe
authors.initials: YZ
authors.lastname: Jin
authors.forename: Xun
authors.initials: X
authors.lastname: Cui
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D000242:Cyclic AMP / Q000096:biosynthesis* / Q000502:physiology; D006321:Heart / Q000187:drug effects / Q000378:metabolism*; D006325:Heart Atria / Q000187:drug effects / Q000378:metabolism; D010477:Perfusion; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000502:physiology*; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D009320:Atrial Natriuretic Factor; D000242:Cyclic AMP