ion channel

(redirected from Ionic channels)
Also found in: Dictionary, Encyclopedia.

i·on chan·nel

a specific macromolecular protein pathway, with an aqueous "pore," which traverses the lipid bilayer of a cell's plasma membrane and maintains or modulates the electrical potential across this barrier by allowing the controlled influx or exit of small inorganic ions such as Na+, K+, Cl-, and Ca2+. It plays an important role in propagation of the action potential in neurons, but also may control transduction of extracellular signals and contraction in muscle cells. In general, ion channels are characterized by their selectivity for certain ions, their specific regulation or gating of these ions, and their specific sensitivity to toxins.

ion channel

n.
A pathway through a protein molecule or complex in a cell membrane that modulates the electrical potential across the membrane by controlling the passage of small inorganic ions into and out of the cell.

ion channel

A protein that spans the lipid bilayer of the cell membrane and regulates the movement of charged particles (e.g., electrolytes) into and out of cells.
See also: channel
References in periodicals archive ?
Moreover, the ionic channel modeling using Markov chains [32] is valid if the sampling time is much longer than the channel protein transition time (order of ps) [33].
Since the multiple voltage-gated ionic channels are concentrated in the dense cluster, multiple stochastic resonance frequencies exist there.
[31.] Hille B (1992) Ionic channels of excitable membranes.
where a is the radius of the ionic channel, [epsilon] and [[epsilon].sub.TRP] are the dielectric permittivity of the membrane and the TRP channels, respectively, and E(r, t ) is the electric field strength in the r point of the membrane at t time.
The intracranial injection assay was performed to investigate whether there would be any direct activity of the toxin in the central nervous system (CNS), once peptides can promote behavioral alterations by acting on receptors and ionic channels on CNS.
In this work we examined whether arylnaphthalene lignans isolated from Taiwania cryptomerioides would affect neuronal ionic channels. For the first time we reported that they could inhibit Kv channels (Fig.
Moreover, the scorpion toxins probably act in the ionic channels at cellular membrane level.
These are further explained in the section about synapses and ionic channels.
The membranes of all these axon sprouts are enriched with ionic channels and various forms of receptors that make the neuroma excitable.
One of these changes is the synthesis of chemical receptors and ionic channels. The repair process is sometimes complicated by neuroma formation.
Probably, this effect could be produced through an effect upon the neuronal excitability by ionic channel modulation, since the voltage gated [K.sup.+] channels from the Kv family are involved in the neuronal signaling, changing the discharge threshold of action potential, its frequency, etc.
The results derived from this study strongly suggest that the [Ca.sup.2+]-dependent chloride currents evoked by the plant extracts are originated by activation of similar ionic channels. Further experiments will, however, be necessary to obtain information concerning the level at which the extracts activate the [Ca.sup.2+] release, and to determine if the I[P.sub.3]-diacylglycerol pathway is activated in Xenopus oocytes exposed to the extracts.