Action Potential Repolarization in Equine Hearts
نویسندگان
چکیده
منابع مشابه
Autonomic nerve stimulation reverses ventricular repolarization sequence in rabbit hearts.
Sympathetic activity and spatial dispersion of repolarization (DOR) have been implicated as mechanisms that promote arrhythmia vulnerability; yet there are no direct measurements of the effects of autonomic nerve stimulation on DOR. Rabbit hearts were perfused in a Langendorff apparatus with full sympathetic and parasympathetic innervation and were optically mapped to measure action potential d...
متن کاملVariability in local action potential durations, dispersion of repolarization and wavelength restitution in aged wild-type and Scn5a+/− mouse hearts modeling human Brugada syndrome
Brugada syndrome is a primary arrhythmia syndrome characterized by loss-of-function mutations in the SCN5A gene, which encodes for the cardiac Na channel. In affected individuals, the risk of developing malignant ventricular arrhythmias and sudden cardiac death are increased. Two leading theories, the depolarization and repolarization hypotheses, have been put forward to explain the underlying ...
متن کاملResilient RTN fast spiking in Kv3.1 null mice suggests redundancy in the action potential repolarization mechanism.
Fast spiking (FS), GABAergic neurons of the reticular thalamic nucleus (RTN) are capable of firing high-frequency trains of brief action potentials, with little adaptation. Studies in recombinant systems have shown that high-voltage-activated K(+) channels containing the Kv3.1 and/or Kv3.2 subunits display biophysical properties that may contribute to the FS phenotype. Given that RTN expresses ...
متن کاملOptical mapping of repolarization and refractoriness from intact hearts.
BACKGROUND Heterogeneities of repolarization (R) across the myocardium have been invoked to explain most reentrant arrhythmias. The measurement of refractory periods (RPs) has been widely used to assess R, but conventional electrode and extrastimulus mapping techniques have not provided reliable maps of RPs. METHODS AND RESULTS Guinea pig hearts were stained with a voltage-sensitive dye to me...
متن کاملAlterations in early action potential repolarization causes localized failure of sarcoplasmic reticulum Ca2+ release.
Depressed contractility of failing myocytes involves a decreased rate of rise of the Ca2+ transient. Synchronization of Ca2+ release from the junctional sarcoplasmic reticulum (SR) is responsible for the rapid rise of the normal Ca2+ transient. This study examined the idea that spatially and temporally dyssynchronous SR Ca2+ release slows the rise of the cytosolic Ca2+ transient in failing feli...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2015
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2014.11.637