Kanamycin이 토끼 단일 심근 세포막의 Ca2+ Current에 미치는 영향

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 Ca2+-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 Ca2+-Tyrode to high Sr2+-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.