caa a22 4500 475744918 CHVBK 20180406123510.0 cr unu---uuuuu 170329e20001001xx s 000 0 eng 10.1023/A:1005653218639 doi (NATIONALLICENCE)springer-10.1023/A:1005653218639 Urocortin hyperpolarizes stomach smooth muscle via activation of Ca2+-sensitive K+ currents [Elektronische Daten] [P. Petkova-Kirova, H. Gagov, D. Duridanova] The effect of urocortin (Uro), a recently discovered neuropeptide with selectivity towards corticotropin-releasing hormone type 2 receptor, was tested on whole cell currents expressed by guinea-pig gastric antrum smooth muscle cells. Uro (1 pmol/l − 1 nmol/l) caused a concentration-dependent increase of Ca2+-sensitive K currents (I K) up to 500% as compared to control currents and did not affect the kinetics and voltage-dependence of inward Ca2+ currents. The I K-increasing effect of Uro was fully antagonized by preliminary emptying of intracellular Ca2+ stores with ryanodine and cyclopiazonic acid, as well as by bath application of selective blockers of adenylyl cyclase and cAMP-dependent protein kinase (PKA), but not by inhibitors of guanylyl cyclase, cGMP-dependent protein kinase, and protein kinase C. Comparable I K increase was obtained by forskolin (activator of adenylyl cyclase), Sp-cAMPS (activator of PKA), or by intracellular application of the catalytic subunit of PKA. It was concluded that Uro binds to a selective receptor in antral smooth muscle cells where it stimulates I K via PKA-dependent increase of Ca2+ concentration near the plasma membrane due to enhanced release from intracellular calcium stores. Kluwer Academic Publishers, 2000 Petkova-Kirova P. Institute of Biophysics, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria aut Gagov H. Institute of Biophysics, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria aut Duridanova D. Institute of Biophysics, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria aut Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/7(2000-10-01), 639-645 0142-4319 21:7<639 2000 21 10974 https://doi.org/10.1023/A:1005653218639 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1005653218639 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Petkova-Kirova P. Institute of Biophysics, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria aut NATIONALLICENCE 700 1- Gagov H. Institute of Biophysics, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria aut NATIONALLICENCE 700 1- Duridanova D. Institute of Biophysics, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria aut NATIONALLICENCE 773 0- Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/7(2000-10-01), 639-645 0142-4319 21:7<639 2000 21 10974 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer