EFFECTS OF THE HOE 694 ON TRANSIENT INWARD CURRENT AND NA＋ -CA2＋ EXCHANGE IN GUINEA PIG CARDIOMYOCYTES
- Author:
Huajun LIU
1
;
Haozhu CHEN
;
Xueyi YANG
;
Jieshi CHENG
Author Information
1. Shanghai Institute of Cardiovascular Diseases ZhongShan Hospital of Shanghai Medical University
- From:
Chinese Medical Sciences Journal
2001;16(1):5-9
- CountryChina
- Language:Chinese
-
Abstract:
Objective. To determine the effects of HOE 694, a new and potent Na＋ -H＋ exchanger blocker, on transient inward current (Iti) and Na＋ -Ca2＋ exchange during hypoxia-reoxygenation in guinea pig cardiomyocytes. Methods. Cardiomyocytes were isolated from adult guinea pig ventricle. Experiment was performed in an experimental chamber that allowed the cells to be exposed to a sufficiently low O2 pressure. The cells were subjected to hypoxia and reoxygenation. The ionic currents were studied with patch clamp technique. Results. In the absence of HOE 694, hypoxia-reoxygenation induced Iti in 12 of 15 experiments; but in cardiomyocytes pretreated with HOE 694 (10～ 50 μ mol/L), the incidence of Iti observed during reoxygenation was reduced to 5 of 11 experiments and 3 of 10 experiments, P0.05 vs control respectively. The Na＋-Ca2＋ exchange current was unaffected by HOE 694 under normoxic condition. However, when cells were pretreated with 10 μ mol/L HOE 694 for 10 min, then subjected to hypoxia condition, the Na＋ Ca2＋ exchange current was significantly inhibited. Conclusions. Blockade of the Na＋ -H＋ exchange by HOE 694 could reduce Ca2＋ overload upon hypoxia-reoxygenation, and inhibition of Na＋ -H＋ exchange may also indirectly decrease Na＋ -Ca2＋ exchange activity during hypoxia.
