Molecular basis and electrophysiological properties of ion channels in rabbit sinoatrial node cells.
| Project/Area Number |
12670697
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Circulatory organs internal medicine
|
|---|
| Research Institution | Tokyo Woman's Medical University |
|---|
Principal Investigator |
HAGIWARA Nobuhisa Tokyo Women 's Medical University. Cardiology, Assistant Professor, 医学部, 助教授 (00180802)
|
|---|
| Project Period (FY) |
2000 – 2001
|
| Project Status |
Completed (Fiscal Year 2001)
|
| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2001: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2000: ¥1,800,000 (Direct Cost: ¥1,800,000)
|
|---|
| Keywords | Sinoatrial node / Transient outward current / Patch clamp method / Ito / Kv4.3 / 再分極相 / パッチクランプ法 |
|---|
| Research Abstract |
The electrophysiological properties of the transient outward current were investigated in voltageclamped single cells from the rabbit sino-atrial node. The current-voltage relationship exhibited a characteristic outward rectification with an activation threshold of -30 mV. External 4-aminopyridine inhibited this current in a dose-dependent manner (IC50 = 0.28 mM, Hill coefficient = 1.38). The steady-state inactivation exhibited a half-maximum voltage of -35 mV and a slope factor of -8.4 mV. The current density of the transient outward current was 6.3 ± 0.5 pA/pF in sino-atrial node cells and 12.3 ± 1.2 pA/pF in atrial cells. The inactivation time constant was faster in sino-atrial node cells (time constants, 4.2 ± 0.5 ms and 26.0 ± 0.6 ms, respectively, for the fast and slow components) than in atrial cells (9.7 ± 1.2 ms and 44.8 ± 3.2 ms, respectively). Recovery from inactivation was much faster in sino-atrial node cells (time constant, 44.7 ± 9.0 ms) than in atrial cells (time constants, 1.39 ± 0.32 s and 6.70 ± 0.1 s, respectively, for the fast and slow components). These results suggest that the kinetic properties, as well as the current density, of the transient outward current differs between sino-atrial node and atrial cells. Taking the current density of Ito at +10 mV as 2.5 ± 0.3 pA/pF gives a total Ito of approximately 100 pA at the. peak of the action potential in rabbit sino-atrial node cells. Thus, Ito may contribute significantly to the repolarization phase in mammalian sino-atrial node cells.
|
Report
(3 results)
Research Products
(21 results)
-
-
-
-
-
-
-
-
[Publications] K, Kajimoto., T, Harada., K, Imamura., N, Matsuda., N, Hagiwara., H, Kasanuki.: "Efficacy of continuous intravenous drip infusion of disopyramide in hypertrophic obstructive cardiomyopathy during cardiogenic shock."J. Cardiol. 32. 197-203 (2000)
Description
「研究成果報告書概要(欧文)」より
Related Report
-
-
-
-
-
-
-
-
-
-
-
-
-
