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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Analysis of Variance, Dose-Response Relationship, Drug, Glyburide, Humans, Hypoglycemic Agents, Ion Channel Gating, Neuropeptides, Neurotransmitter Agents, Peptides, Pituitary Adenylate Cyclase-Activating Polypeptide, Potassium Channel Blockers, Potassium Channels, Pulmonary Artery, Regression Analysis, Statistics, Nonparametric, Vasodilator Agents.
user
Do pituitary adenylate cyclase activating peptides relax human pulmonary arteries by opening of KATP and KCa channels? Context: Pituitary adenylate cyclase activating peptides (PACAPs) are potent endothelium independent dilators of human coronary arteries; however, their effects on human pulmonary arteries are unknown. The vasorelaxant effects of PACAP27 on human pulmonary segmental arteries were studied and the specific potassium (K+) channel regulatory mechanisms in the vasorelaxant effects were tested by means of isometric contraction experiments. PACAP27 produced dose dependent relaxations of 10 microM rings preconstricted with prostaglandin F2 alpha (PGF2 alpha) with half maximal relaxation (IC50) at 17 nM. Pretreatment of the vessels with the ATP sensitive K+ (KATP) channel blocker glibenclamide (1 microM) or with the Ca2+ activated K+ (KCa) channel blocker iberiotoxin (100 nM) inhibited the PACAP27 induced relaxation.
assistant
These results provide evidence that PACAPs are potent vasodilators of human pulmonary arteries and that this relaxation might be mediated by opening of KATP and KCa channels. Final Decision: yes