4-Aminopyridine (4-AP)-sensitive transient outward current ( I to) has been observed in the sinoatrial node, but its role is unknown. The effect of block of I to by 5 mM 4-AP on small ball-like tissue preparations (diameter ∼0.3-0.4 mm) from different regions of the rabbit sinoatrial node has been investigated. 4-AP elevated the plateau, prolonged the action potential, and decreased the maximum...

In hippocampal neurons, a slowly inactivating aminopyridine-sensitive transient potassium current, D-current, influences the time course of action potential repolarization and therefore activity-dependent Ca2+ entry. We used high-speed optical recording techniques to study the effects of selectively inhibiting D-current with 4-AP (40 microM) on transmission at the Schaffer collateral (CA3)-CA1 ...

objective: resveratrol, a phytoalexin, has a wide range of desirable biological actions. despite a growing body of evidence indicating that resveratrol induces changes in neuronal function, little effort, if any, has been made to investigate the cellular effect of resveratrol treatment on intrinsic neuronal properties. materials and methods: this experimental study was performed to examine the ...

To study the mechanism of aluminium toxicity in plant cells, the effects of aluminium on the electrogenesis of plasma membrane were investigated. We analyzed Al3+ induced membrane potential (Em) changes and potential changes during generation of the action potential (AP) in the internodal cells of Nitellopsis obtusa. Al3+ modified Em decrease significantly. Al3+ didn’t attenuate the amplitude o...

35 patients with unilateral sensorineural impairment and hearing levels within the normal range in the opposite ears were investigated by bilateral transtympanic electrocochleography (tiecog). only 19 patients (54%) satisfied the criteria for meniere's disease and 16 patients (46%) showed sensorineural impairment due to other etiologies. clinical studies have focused exclusively on the a m...

We investigated the electrophysiological effects of cardiac hypertrophy induced by renal hypertension in rats by comparing transmembrane action potentials (AP) recorded from the papillary muscles of hypertensive (HBP) and normal (SHAM) rats. No significant difference was found between HBP and SHAM AP with regard to resting membrane potential (RMP), action potential amplitude (AMP), overshoot (O...

Episodic ataxia type 2 (EA2) is a hereditary cerebellar ataxia associated with mutations in the P/Q-type voltage-gated calcium (Ca(2+)) channels. Therapeutic approaches for treatment of EA2 are very limited. Presently, the potassium (K(+)) channel blocker 4-aminopyridine (4-AP) constitutes the most promising treatment, although its mechanism of action is not understood. Here we show that, in co...

Action potentials trigger synchronous and asynchronous neurotransmitter release. Temporal properties of both types of release could be altered in an activity-dependent manner. While the effects of activity-dependent changes in synchronous release on postsynaptic signal integration have been studied, the contribution of asynchronous release to information transfer during natural stimulus pattern...

BASS, kz G. htitution of the action potential in cat papillary muscle. Am. J. Physiol. Z%(6) : 17 17-l 724. 1975.-Membrane recovery (electrical restitution) following an action potential (AP) was studied in isolated, electrically driven cat papillary muscle by interpolation of test extrasystoles at various delays in the interval between two AP’s (recorded with glass microelectrodes). Curves des...

Electrophysiological dysfunction of Purkinje cells causes cerebellar ataxia. Recent studies indicated that 4-aminopyridine (4-AP) can prevent the attacks in patients with episodic ataxia type 2. However, the cellular mechanism(s) by which 4-AP might be beneficial for the improvement of motor function remain unclear. Here, electrophysiological and behavioural consequences of in vivo co-treatment...