Noisy saltatory spike propagation along myelinated axons is studied within a stochastic HodgkinHuxley model. The intrinsic noise (whose strength is inverse proportional to the nodal membrane size) arising from fluctuations of the number of open ion channels influences the dynamics of the membrane potential in a node of Ranvier where the sodium ion channels are predominantly localized. The nodes...

Cell death in cerebral ischemia is presumably initiated by neural excitotoxicity resulted from the dysfunction of inhibitory neurons in early stage. Molecular processes underlying the ischemic injury of inhibitory neurons remain to be elusive, which we investigated by biochemical manipulations with cellular imaging and patch clamp at GFP-labeled GABAergic cells in cortical slices. Ischemia indu...

The electrical properties of enzymatically isolated olfactory receptor cells were studied with whole-cell patch clamp. Voltage-dependent currents could be separated into three ionic components: a transient inward sodium current, a sustained inward calcium current, and an outward potassium current. Three components of the outward current could be identified by their gating and kinetics: a calciu...

Noisy saltatory spike propagation along myelinated axons is studied within a stochastic Hodgkin-Huxley model. The intrinsic noise (whose strength is inversely proportional to the nodal membrane size) arising from fluctuations of the number of open ion channels influences the dynamics of the membrane potential in a node of Ranvier where the sodium ion channels are predominantly localized. The no...

Spike-frequency adaptation is a prominent aspect of neuronal dynamics that shapes a neuron's signal processing properties on timescales ranging from about 10 ms to >1 s. For integrate-and-fire model neurons spike-frequency adaptation is incorporated either as an adaptation current or as a dynamic firing threshold. Whether a physiologically observed adaptation mechanism should be modeled as an a...

Early infantile epileptic encephalopathy or EIEE (Ohtahara syndrome OS) is a kind of intractable seizure that begins in neonatal age with sudden onset of tonic spasms in series or single suppression-burst S-B in EEG.I Imaging shows anatomic defects such as migration disorders and generalized atrophy" with essentially normal metabolic tests. The seizures often change to West's syndrome (WS) ...

AIM Papaverine is a vasodilator agent that is an opium alkaloid. It exhibits its effects by inhibiting phosphodiesterase enzyme. Papaverine administration is widely used to avoid symptomatic vasospasm after subarachnoid hemorrhage. We aim in this research to study the effects of papaverine on the epileptic discharges stimulated by penicillin. MATERIAL AND METHODS Adult female Wistar rats (220...

Antidromic action potentials following distal stimulation of motor axons occasionally fail to invade the soma of alpha motoneurons in spinal cord, due to their passing through regions of high non-uniformity. Morphologically detailed conductance-based models of cat spinal alpha motoneurons have been developed, with the aim to reproduce and clarify some aspects of the electrophysiological behavio...

Layer V pyramidal cells of the somatosensory cortex operate with two spike initiation zones. Sub-threshold depolarizations are strongly attenuated along the apical dendrite linking the somatic and distal dendritic spike initiation zones. Sodium action potentials, on the other hand, are actively back-propagating from the axon hillock into the apical tuft. There they can interact with local excit...

The role of the electrogenic Na(+)-Ca(2+)-exchange mechanism in regulating the spike activity of the ureter was studied. The ureter cells were shown to be capable of generating action potentials (AP) in sodium-free Krebs solution. The time during which the spikes are generated is in exponential dependence on the concentration of calcium ions in the medium, [Ca2+]o within 2.5 to 15 mmol/l. Simul...