A TTX-sensitive inward sodium current contributes to spontaneous activity in newborn rabbit sino-atrial node cells.
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چکیده
منابع مشابه
Current-dependent Block of Rabbit Sino-Atrial Node If Channels by Ivabradine
"Funny" (f-) channels have a key role in generation of spontaneous activity of pacemaker cells and mediate autonomic control of cardiac rate; f-channels and the related neuronal h-channels are composed of hyperpolarization-activated, cyclic nucleotide-gated (HCN) channel subunits. We have investigated the block of f-channels of rabbit cardiac sino-atrial node cells by ivabradine, a novel heart ...
متن کاملA slowly inactivating sodium current contributes to spontaneous diastolic depolarization of atrial myocytes.
Diastolic depolarization (DD) of atrial myocytes can lead to spontaneous action potentials (APs) and, potentially, atrial tachyarrhythmias. This study examined the hypotheses that 1) a slowly inactivating component of the Na(+) current (referred to as late I(Na)) may contribute to DD and initiate AP firing and that 2) blocking late I(Na) will reduce spontaneous and induced firing of APs by atri...
متن کاملComparison of Hyperpolarization-Activiated Current “if ” on the Rate of Spontaneous Activity and Cycle Length before and after Cutting of Atrial Muscle away from Intact Sinoatrial Node of Rabbit
It has been shown that the hyperpolarization-activated current “if” that is blocked by 2 mM Cs+ plays a minor role on pacemaker activity of the center and a major role on activity of the periphery of rabbit intact sino-atrial node. On the other hand some investigations showed that if the atrial muscle, surrounding the sino-atrial node, is cut away there is a shift in leading pacemaker site from...
متن کاملFacilitation of the L-type calcium current in rabbit sino-atrial cells: effect on cardiac automaticity.
OBJECTIVE The L-type Ca(2+) current (I(Ca,L)) contributes to the generation and modulation of the pacemaker action potential (AP). We investigated facilitation of I(Ca,L) in sino-atrial cells. METHODS Facilitation was studied in regularly-beating cells isolated enzymatically from young albino rabbits (0.8-1 kg). We used the whole-cell patch-clamp technique to vary the frequency of the test de...
متن کاملAtrial tachycardia secondary to sino-atrial node reentry.
In one patient reprodncibk episodes of sMal tachyear(200 msec, control; 70 msec, atropine) and sustained dia conld be elicited via programmed atrial premature atrial tachycardia no longer could be elicited. These dcpoluizations. Evllodion of the elechpphysiologic studies mpport the concept that h a t t i a l reciprocation shldks suggested that the most tikely mechanism was can be a mechanism re...
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ژورنال
عنوان ژورنال: The Journal of Physiology
سال: 1996
ISSN: 0022-3751
DOI: 10.1113/jphysiol.1996.sp021285