ion channel

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ion channel

[′ī‚än ¦chan·əl]
(biophysics)
References in periodicals archive ?
The mean firing rate, i.e., the number of spikes per second, is due to the operating point fixed by the OHC and to the endogenous noise related to the number of ionic channels. To quantify the level of firing inhibition, and thus of tinnitus suppression, induced by the electric stimulation, it is necessary to introduce a sensitive technique.
To account for the random gating of sodium and potassium channels, the ionic current densities [I.sub.Na] = [g.sub.Na] (V-[E.sub.Na]) and [I.sub.K] = [g.sub.K](V - [E.sub.K]) were calculated using a channel-state-tracking algorithm [27, 28] where Markov chains [27, 29] modeled independent gating particles belonging to each ionic channel.
The field-strength of the cell membrane is huge: E [approximately equal to] [10.sup.7] V / m consequently, its effect on the ionic channels is expected and it will likely polarise the transmembrane proteins until their saturated polarisation value is reached because the rotational diffusion is stronger in the membrane than the translational [60] diffusion.
where [I.sub.ion] is Hodgkin-Huxley type ionic current, as we have in the presynaptic region while [I.sub.X] is synaptic current through ionic channels. The postsynaptic current occurs as a result of rise and fall in potential caused by the firing of the presynaptic neuron.
Primers (Table 1) for each ionic channel studied, bGH gene, and [beta]-actin were designed for measuring gene expression following the kit Pyrostart fast PCR Master Mix (Fermentas) procedure with the PCR protocol 94[degrees]C/5min, 35 cycles 94[degrees]C/30 sec + 57.5[degrees]C/30 sec + 72[degrees]C/1min, and 72[degrees]C/10 min.
Neuronal nicotinic acetylcholine receptors (nAChRs) belong to the pentameric superfamily of Cys-loop ligand gated ionic channels. They are composed of either homomeric a or heteromeric [alpha] and [beta] subunits assembled from a family of 12 distinct neuronal nicotinic subunits ([alpha]2-[alpha]10; [beta]2-[beta]4) [5].
Not much is known about the effects of lignans on ionic channels. The only plant lignan known to affect [K.sup.+] channels is NDGA.
They refer that the scorpion toxins probably act in the ionic channels at cellular membrane level.
This is in part because of advances in understanding the chemical messengers (neurotransmitters) released by nerve cells and voltage-generating proteins (ionic channels) housed on nerve-cell membranes that participate in the transmission of normal sensation.
But the electricity in the ionic channels can zip through the thin glass dead-end without harming the device in the process.
glauca could be due in part to the action of GB through a mechanism involving the participation of ionic channels or the regulation of the GAB[A.sub.A] receptor in a different place than that for benzodiazepines.
the oocytes with their surrounding follicular cells, are a very useful cellular model for studying neurotransmitter and hormone receptors, ionic channels and the intracellular mechanisms that operate them (for reviews see, Miledi et al., 1989; Arellano et al., 1996).