Action of Cromakalim on Potassium Membrane Conductance in Isolated Heart Myocytes of Frog

Overview

Journal Br J Pharmacol

Publisher Wiley

Specialty Pharmacology

Date 1990 Jul 1

PMID 2117982

Citations 1

Authors

R Pilsudski

O Rougier

Y Tourneur

Affiliations

Soon will be listed here.

Abstract

1. The effects of cromakalim on membrane currents were studied at 20 degrees C in frog atrial and ventricular cells in patch clamp recording using the whole cell configuration. 2. When cromakalim (1 microM) was applied in the external medium, a time-independent current was activated in a few minutes. Cromakalim induced a weak increase of inward membrane currents recorded during hyperpolarization and a large increase of outward membrane currents recorded during depolarization. 3. The current voltage relationship of the cromakalim-induced current reversed near EK and rectified in the outward direction. 4. The cromakalim-activated current was inhibited by external application of cesium (20 mM), barium (1.8 mM), tolbutamide (1 mM) and glibenclamide (1 microM). 5. The effects of cromakalim were insensitive to a cytosolic increase in adenosine 5'-triphosphate (ATP, 3-5 mM). Cromakalim had no effects when applied in the cell. 6. Our results confirm that cromakalim activates an IK(ATP)-like conductance and suggest that the effects of the drug are due to an action on the external side of the membrane and are independent of the ATP cell content.

Citing Articles

SR47063, a potent channel opener, activates KATP and a time-dependent current likely due to potassium accumulation.

Tourneur Y, Marion A, Gautier P J Membr Biol. 1994; 142(3):337-47.

PMID: 7707361 DOI: 10.1007/BF00233440.

References

Schmid-Antomarchi H, De Weille J, Fosset M, Lazdunski M . The antidiabetic sulfonylurea glibenclamide is a potent blocker of the ATP-modulated K+ channel in insulin secreting cells. Biochem Biophys Res Commun. 1987; 146(1):21-5. DOI: 10.1016/0006-291x(87)90684-x. View

Quast U . Effect of the K+ efflux stimulating vasodilator BRL 34915 on 86Rb+ efflux and spontaneous activity in guinea-pig portal vein. Br J Pharmacol. 1987; 91(3):569-78. PMC: 1853539. DOI: 10.1111/j.1476-5381.1987.tb11250.x. View

Scholtysik G . Evidence for inhibition by ICS 205-930 and stimulation by BRL 34915 of K+ conductance in cardiac muscle. Naunyn Schmiedebergs Arch Pharmacol. 1987; 335(6):692-6. DOI: 10.1007/BF00166988. View

Simmons M, Hartzell H . A quantitative analysis of the acetylcholine-activated potassium current in single cells from frog atrium. Pflugers Arch. 1987; 409(4-5):454-61. DOI: 10.1007/BF00583801. View

Hollingsworth M, Amedee T, Edwards D, Mironneau J, Savineau J, Small R . The relaxant action of BRL 34915 in rat uterus. Br J Pharmacol. 1987; 91(4):803-13. PMC: 1853592. DOI: 10.1111/j.1476-5381.1987.tb11279.x. View

Shetty S, Weiss G . Dissociation of actions of BRL 34915 in the rat portal vein. Eur J Pharmacol. 1987; 141(3):485-8. DOI: 10.1016/0014-2999(87)90570-x. View

Carmeliet E, Biermans G, Callewaert G, Vereecke J . Potassium currents in cardiac cells. Experientia. 1987; 43(11-12):1175-84. DOI: 10.1007/BF01945519. View

Quast U, Cook N . Leiurus quinquestriatus venom inhibits BRL 34915-induced 86Rb+ efflux from the rat portal vein. Life Sci. 1988; 42(7):805-10. DOI: 10.1016/0024-3205(88)90654-6. View

Cook N, Hof R . Cardiovascular effects of apamin and BRL 34915 in rats and rabbits. Br J Pharmacol. 1988; 93(1):121-31. PMC: 1853774. DOI: 10.1111/j.1476-5381.1988.tb11412.x. View

10.

Ashcroft F . Adenosine 5'-triphosphate-sensitive potassium channels. Annu Rev Neurosci. 1988; 11:97-118. DOI: 10.1146/annurev.ne.11.030188.000525. View

11.

Osterrieder W . Modification of K+ conductance of heart cell membrane by BRL 34915. Naunyn Schmiedebergs Arch Pharmacol. 1988; 337(1):93-7. DOI: 10.1007/BF00169483. View

12.

Quast U, Scholtysik G, Weir S, Cook N . Pertussis toxin treatment does not inhibit the effects of the potassium channel opener BRL 34915 on rat isolated vascular and cardiac tissues. Naunyn Schmiedebergs Arch Pharmacol. 1988; 337(1):98-104. DOI: 10.1007/BF00169484. View

13.

Escande D, Thuringer D, Leguern S, Cavero I . The potassium channel opener cromakalim (BRL 34915) activates ATP-dependent K+ channels in isolated cardiac myocytes. Biochem Biophys Res Commun. 1988; 154(2):620-5. DOI: 10.1016/0006-291x(88)90184-2. View

14.

Sanguinetti M, Scott A, Zingaro G, Siegl P . BRL 34915 (cromakalim) activates ATP-sensitive K+ current in cardiac muscle. Proc Natl Acad Sci U S A. 1988; 85(21):8360-4. PMC: 282434. DOI: 10.1073/pnas.85.21.8360. View

15.

Quast U, Baumlin Y . Comparison of the effluxes of 42K+ and 86Rb+ elicited by cromakalim (BRL 34915) in tonic and phasic vascular tissue. Naunyn Schmiedebergs Arch Pharmacol. 1988; 338(3):319-26. DOI: 10.1007/BF00173407. View

16.

Pilsudski R, Rougier O, Tourneur Y . Activation of an ATP-sensitive K+ current is promoted by internal GDP in frog atrial myocytes. Pflugers Arch. 1989; 414 Suppl 1:S177. DOI: 10.1007/BF00582292. View

17.

Escande D, Thuringer D, Le Guern S, COURTEIX J, Laville M, Cavero I . Potassium channel openers act through an activation of ATP-sensitive K+ channels in guinea-pig cardiac myocytes. Pflugers Arch. 1989; 414(6):669-75. DOI: 10.1007/BF00582134. View

18.

Hume J, Giles W . Ionic currents in single isolated bullfrog atrial cells. J Gen Physiol. 1983; 81(2):153-94. PMC: 2215568. DOI: 10.1085/jgp.81.2.153. View

19.

Noma A . ATP-regulated K+ channels in cardiac muscle. Nature. 1983; 305(5930):147-8. DOI: 10.1038/305147a0. View

20.

Hamilton T, Weir S, Weston A . Comparison of the effects of BRL 34915 and verapamil on electrical and mechanical activity in rat portal vein. Br J Pharmacol. 1986; 88(1):103-11. PMC: 1917115. DOI: 10.1111/j.1476-5381.1986.tb09476.x. View