Muscarinic control of the hyperpolarization-activated current (if) in rabbit sino-atrial node myocytes.
نویسندگان
چکیده
منابع مشابه
Inhibition by genistein of the hyperpolarization-activated cation current in porcine sino-atrial node cells.
1 The hyperpolarization-activated cation current (If) was recorded in single pacemaker cells of the porcine sino-atrial node, and the effects of genistein, an isoflavone inhibitor of tyrosine-specific protein kinases was investigated by the whole-cell patch clamp technique. 2 Genistein (20-500 microM) decreased If in a dose-dependent manner with an IC50 value of 62.3 microM and a maximum inhibi...
متن کاملCurrent-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 کاملHyperpolarization-Activated Current, If, in Mathematical Models of Rabbit Sinoatrial Node Pacemaker Cells
A typical feature of sinoatrial (SA) node pacemaker cells is the presence of an ionic current that activates upon hyperpolarization. The role of this hyperpolarization-activated current, If, which is also known as the "funny current" or "pacemaker current," in the spontaneous pacemaker activity of SA nodal cells remains a matter of intense debate. Whereas some conclude that If plays a fundament...
متن کاملHyperpolarization activated cation current (If) in cardiac myocytes from pulmonary vein sleeves in the canine with atrial fibrillation
OBJECTIVE To investigate the characteristics of ectopic automaticity and cation current (I(f)) of cardiac myocytes from pulmonary vein sleeves (PVs) in canines with atrial fibrillation. METHODS The canines (8-10 years old) were subjected to long-term, rapid atrial pacing (RAP) for 10 weeks, which induced the atrial fibrillation model. Disassociation of PVs of canines yielded single cardiac my...
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...
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ژورنال
عنوان ژورنال: The Journal of Physiology
سال: 1988
ISSN: 0022-3751
DOI: 10.1113/jphysiol.1988.sp017344