The effect of levobunolol hydrochloride on the calcium and potassium channels in isolated ventricular myocytes of guinea pig

Journal of Tongji Medical University = Tong Ji Yi Ke Da Xue Xue Bao
M TangH Luo

Abstract

The effects of levobunolol hydrochlorid (Bun) on the type L calcium channel currents (ICA) and delayed rectifier potassium channel currents (IK) in isolated ventricular myocytes of guinea pig were studied by using patch clamp whole cell recording techniques. The results were showed that: 1) Bun caused a dose dependent decrease in ICA and a dose-dependent increase in IK of the ventricular myocytes. The threshold concentrations of Bun for ICA and IK were 10(-8) mol/L and 10(-7) mol/L respectively. The maximum effective concentration of Bun for bot ICA and IK was 3x10(-5) mol/L, and half-maximal concentration was 3x10(-6) mol/L; 2) IK was blocked by 2x100(-6) mol/L tetraethylammonium (TEA). A concentration of 3x10(-6) mol/L Bun showed a decreasing effect on the ICA as revealed by the current-voltage relationship curve, i.e., Bun caused an elevation of the curve;3) When ICA was blocked by 2x10(-6) mol/L Isoptin (Verapamil), at a concentration of 3x10(-6) mol/L Bun showed an increasing effect on IK and the effect could be blocked by TEA. The above-mentioned results indicated that Bun had an inhibitory effect on ICA and a fascilitatory effect on IK. The results suggested that the molecular mechanisms of antihypertensive, heart rate s...Continue Reading

References

Sep 1, 1987·Pflügers Archiv : European journal of physiology·J HeschelerW Trautwein
Jan 1, 1986·General Pharmacology·G D Novack
Aug 1, 1981·Pflügers Archiv : European journal of physiology·O P HamillF J Sigworth
Feb 1, 1983·American Journal of Ophthalmology·L G PartamianM Gordon
Oct 1, 1982·Pflügers Archiv : European journal of physiology·G Isenberg, U Klockner

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