1998 Fiscal Year Final Research Report Summary
Role of ATP sensitive K^+ channel in intracellular Ca^<2+> regulation.
Project/Area Number |
08670826
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Circulatory organs internal medicine
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Research Institution | Jikei University, School of Medicine |
Principal Investigator |
MCHIZUKI Seibu JIKEI UNIVERSITY SCHOOL OF MEDICINE DEPARTMENT OF MEDICINE 4 PROFESSOR, 医学部, 教授 (20130205)
|
Co-Investigator(Kenkyū-buntansha) |
SEKI Shingo LECTURER, 医学部, 講師 (70179323)
TANIGUCHI Masayuki LECTURER, 医学部, 講師 (70179844)
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Project Period (FY) |
1996 – 1998
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Keywords | ATP sensitive K^+ channel / calcium / fura-2 / ischemia / sodium calcium exhanger |
Research Abstract |
OBJECTIVE : We investigated the roles of ATP sensitive K^+ channel (K_<ATP>) and Na^+/Ca^<2+> exchanger in intracellular Ca^<2+> regulation. METHODS : Single enzymatically isolated guinea pig ventricular myocytes were exposed to chemical hypoxia with glucose-free Tyrode solution containing 1mM sodium dithionite and were reoxygenated. Intracellular Ca^<2+> concentration ([Ca^<2+>]i) was measured ratiometrically using fura-2 with simultaneous measurement of cell length. Isolated hearts from Sprague-Dawley rats were retrogradely perfused and [Ca^<2+>]i was monitored using fura-2. Ischemia was induced by reduction of flow to 10% of control with electrical pacing. RESULTS : Hypoxia produced a decrease in Ca^<2+> transient amplitude and an increase in resting [Ca^<2+>]i. K_<ATP> operner accelerated the shortening of action potential duration and suppressed the hypoxic increase in resting [Ca^<2+>]i. The increase in [Ca^<2+>]i induced by Na^+-free exposure was inhibited during hypoxia. Ischemia also produced an increase in diastolic [Ca^<2+>]i. Treatment of reverse mode Na^+/Ca^<2+> exchanger blocker attenuated the increase in diastolic [Ca^<2+>]i during sustained ischemia and accelerated normalization of [Ca^<2+>] i after reperfusion. CONCLUSIONS : Both K_<ATP> and Na^+/Ca^<2+> exchanger were importantly involved in intracellular Ca^<2+> regulation during ischemia and reperfusion.
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Research Products
(14 results)