caa a22 4500 469077980 CHVBK 20180323132940.0 cr unu---uuuuu 170328e19921201xx s 000 0 eng 10.1007/BF00168744 doi (NATIONALLICENCE)springer-10.1007/BF00168744 K+ channel openers, cromakalim and Ki4032, inhibit agonist-induced Ca2+ release in canine coronary artery [Elektronische Daten] [Toshio Yamagishi, Teruyuki Yanagisawa, Norio Taira] Summary: The effects of K+ channel openers, cromakalim and an acetoxyl derivative of KRN 2391 (Ki 4032), were studied on force of contraction, increases in intracellular calcium concentration ([Ca2+]i) measured by fura-2 and inositol 1,4,5-trisphosphate (IP3) production induced by the thromboxane A2 analogue, U46619, in canine coronary arteries. Upon single dose applications of U46619 at 300 nmol/l, phasic and tonic increases in [Ca2+]i and force were seen, which were almost abolished by cromakalim (10 μmol/l) and Ki4032 (100 μmol/l).In the absence of extracellular Ca2+, U46619 induced a transient increase in [Ca2+]i with a contraction. Cromakalim (0.01-10 μmol/l) and Ki4032 (0.1-100 μmol/l) concentration-dependently inhibited the increases in [Ca2+]i and contraction. The inhibitory effects of cromakalim and Ki4032 were blocked by the K+ channel blocker tetrabutylammonium (TBA) and counteracted by 20 mmol/l KCl-induced depolarization. Cromakalim and Ki4032 did not affect caffeine-induced Ca2+ release. Cromakalim reduced U46619-induced IP3 production significantly and TBA blocked this inhibitory effect. These results suggest that the hyperpolarization of the plasma membrane by K+ channel openers inhibits the production of IP3 and Ca 2+ release from intracellular stores related to stimulation of the thromboxane A2 receptor. Springer-Verlag, 1992 K+ channel openers nationallicence Tetrabutylammonium (TBA) nationallicence Thromboxane A2 analogue nationallicence Inositol 1,4,5-trisphosphate nationallicence Ca2+ release nationallicence Yamagishi Toshio Department of Pharmacology, Tohoku University School of Medicine, 2-1 Seiryo-machi, 980, Aoba-ku, Sendai, Japan aut Yanagisawa Teruyuki Department of Pharmacology, Tohoku University School of Medicine, 2-1 Seiryo-machi, 980, Aoba-ku, Sendai, Japan aut Taira Norio Department of Pharmacology, Tohoku University School of Medicine, 2-1 Seiryo-machi, 980, Aoba-ku, Sendai, Japan aut Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/6(1992-12-01), 691-700 0028-1298 346:6<691 1992 346 210 https://doi.org/10.1007/BF00168744 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00168744 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yamagishi Toshio Department of Pharmacology, Tohoku University School of Medicine, 2-1 Seiryo-machi, 980, Aoba-ku, Sendai, Japan aut NATIONALLICENCE 700 1- Yanagisawa Teruyuki Department of Pharmacology, Tohoku University School of Medicine, 2-1 Seiryo-machi, 980, Aoba-ku, Sendai, Japan aut NATIONALLICENCE 700 1- Taira Norio Department of Pharmacology, Tohoku University School of Medicine, 2-1 Seiryo-machi, 980, Aoba-ku, Sendai, Japan aut NATIONALLICENCE 773 0- Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/6(1992-12-01), 691-700 0028-1298 346:6<691 1992 346 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer