Hyperthyroidism selectively modified a transient potassium current in rabbit ventricular and atrial myocytes.
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چکیده
منابع مشابه
The antiestrogen tamoxifen blocks the delayed rectifier potassium current, IKr, in rabbit ventricular myocytes.
Tamoxifen is an antiestrogen drug commonly used to treat breast cancer and has been shown to cause prolongation of the electrocardiographic QT interval in humans. Because QT prolongation could influence cardiac arrhythmias, we sought to determine the electrophysiologic mechanism(s) underlying the tamoxifen action. The whole-cell patch-clamp technique was used to study the effect of tamoxifen on...
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Transient outward K+ current (I to) downregulation following sustained tachycardia in vivo is usually attributed to tachycardiomyopathy. This study assessed potential direct rate regulation of cardiac I(to) and underlying mechanisms. Cultured adult canine left ventricular cardiomyocytes (37 degrees C) were paced continuously at 1 or 3 Hz for 24 hours. I to was recorded with whole-cell patch cla...
متن کاملDepressed transient outward potassium current density in catecholamine-depleted rat ventricular myocytes.
The effect of catecholamine depletion (induced by prior treatment with reserpine) was studied in Wistar rat ventricular myocytes using whole cell voltage-clamp methods. Two calcium-independent outward currents, the transient outward potassium current (I(to)) and the sustained outward potassium current (I(sus)), were measured. Reserpine treatment decreased tissue norepinephrine content by 97%. A...
متن کاملEffect of acidosis on transient outward potassium current in isolated rat ventricular myocytes.
The effect of acidosis on the transient outward K(+) current (I(to)) of rat ventricular myocytes has been investigated using the perforated patch-clamp technique. When the holding potential was -80 mV, depolarizing pulses to potentials positive to -20 mV activated I(to) in subepicardial cells but activated little I(to) in subendocardial cells. Exposure to an acid solution (pH 6.5) had no signif...
متن کاملNeuropeptide Y increases 4-aminopyridine-sensitive transient outward potassium current in rat ventricular myocytes.
1. The modulation of 4-aminopyridine sensitive transient outward potassium current (4-AP I(to)) by neuropeptide Y (NPY) (100 nM) in rat ventricular myocytes was examined using the whole cell voltage-clamp technique. 2. Continuous exposure to NPY (100 nM) for 3 - 6 h significantly increased 4-AP I(to) density. The stimulation of 4-AP I(to) density by NPY was concentration-dependent (EC(50)=10 nM...
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ژورنال
عنوان ژورنال: The Journal of Physiology
سال: 1992
ISSN: 0022-3751
DOI: 10.1113/jphysiol.1992.sp019383