Effect of Kanamycin on Calcium Current of Rabbit Ventricular Myocyte

Ahn, Duck Sun; Park, Kook In; Kang, Bok Soon

Abstract

It has been reported that kanamycin, a useful agent in the treatment of gram-negative and other infectious disease, has a negative inotropic action in isolated cardiac muscle preparation and also it decreases the amplitude of high K+ -induced action potential of guinea pig atrium. These findings imply that kanamycin has a property of Ca2+ antagonist. In this study, the effects of kanamycin on cardiac Ca2+ current were investigated in isolated rabbit ventricular cells by using a whole cell clamp nethod.The results are summarized as follows ; 1) Kanamycin caused a depression fo cardiac Ca2+ current in a dose dependent manner and its effect was observed in a whole memberane potential renge. 2) The decreasing effect of kanamycin on Ca2+ current was inhibited by high Ca(2+)-Tyrode solution and such inhibition was also observed in high Sr2+-Tyrode solution, but in the case of Cd2+, well known inorganic Ca2+ antagonist, the current through Ca2+ channel was greatly decreased when the perfuaste was changed from high Ca(2+)-Tyrode to high Sr(2+)-Tyrode solution. 3) In the presense of kanamycin, the decreasing pattern of Ca2+current by repetitve depolarization was not specific as in the case of verapamil. 4) Neomycin decreased Ca2+ current similar to kanamycin.From the above result, it may be concluded that kanamycin has competitive antagonistin effect on cardiac Ca2+ current.