We have studied the effects of the potassium-blocking agent 4-aminopyridine (4-AP) on the action potential and membrane currents of the sheep cardiac Purkinje fiber. 4-AP slowed the rate of phase 1 repolarization and shifted the plateau of the action potential to less negative potentials. In the presence of 4-AP, the substitution of sodium methylsulfate or methanesulfonate for the NaCl of Tyrod...

introduction: although aging is the most important risk factor for alzheimer's disease (ad), there is evidence indicating that neuroinflammation may contribute to the development and progression of the disease. several studies indicated that minocycline may exert neuroprotective effects in rodent models of neurodegenerative diseases. nevertheless, there are also other studies implying that...

BACKGROUND AVE0118 (2'-{[2-(4-Methoxy-phenyl)-acetylamino]-methyl}-biphenyl-2-carboxylic acid (2-pyridin-3-yl-ethyl)-amide) blocks atrial ultrarapid delayed rectifier currents (I(Kur)) and prolongs the atrial action potential (AP) plateau without affecting ventricular repolarisation. In patients with atrial contractile dysfunction due to atrial tachyarrhythmias, this response might increase atr...

Natriuretic peptides seem to be a potent regulator of cell Ca2+ signalling in their action on the cardiovascular system. It was therefore the aim of this study to investigate the effect(s) of B-type natriuretic peptide (BNP) on the action potential and the L-type calcium current (I(CaL)) in the rat left ventricular myocytes. Perforated and whole cell patch clamp technique was used to record act...

To determine whether the alpha-dendrotoxin (alpha-DTX)-sensitive current [D current, slow inactivating transient current (I(D))] contributes to the modification of neuronal function in small-diameter adult rat trigeminal ganglion (TG) neurons insensitive to 1 microM tetrodotoxin (TTX), we performed two different types of experiments. In the voltage-clamp mode, two distinct K+ current components...

1. We used intracellular microelectrodes to record the membrane potential (Vm) of intact murine colonic smooth muscle. Electrical activity consisted of spike complexes separated by quiescent periods (Vm approximately -60 mV). The spike complexes consisted of about a dozen action potentials of approximately 30 mV amplitude. Tetraethylammonium (TEA, 1-10 mM) had little effect on the quiescent per...

BACKGROUND Atrial fibrillation (AF) arises from abnormalities in atrial structure and electrical activity. Microelectrode arrays (MEA) is a real-time, nondestructive measurement of the resting and action potential signal, from myocardial cells, to the peripheral circuit of electrophysiological activity. This study examined the field action potential duration (fAPD) of the right atrial appendage...

Action-potential-induced LTD (AP-LTD) is a form of synaptic plasticity that reduces synaptic strength in CA1 hippocampal neurons firing antidromically during sharp-wave ripples. This firing occurs during slow-wave sleep and quiet moments of wakefulness, which are periods of offline replay of neural sequences learned during encoding sensory information. Here we report that rapid and persistent d...

Simultaneous recordings of contractile tension and transmembrane potentials from canine ventricular tissue yielded a consistent correlation of action potential (AP) alteration with contractile change associated with abrupt rate change. The AP terminating a relative prolongation of the cycle-length manifested shortening of phase 2 with lengthening of phase 3 and was associated with potentiation ...

Resting and action potentials were recorded from superfused strips of frog ventricle. Reducing the bathing calcium concentration ([Ca2+]0) with or without ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetraacetate (EGTA) prolongs the action potential (AP). The change in the duration of the AP extends over many minutes, but is rapidly reversed by restoring calcium ions. Other changes (e.g....