Gate of ion channel

Structural models for voltage-dependent gating of ion channels must identify the voltage-sensors or gating charges (Fig. 6-5A) within the channel structure and suggest a plausible mechanism for transmembrane movement... 

Taken together, the limited experiments conducted using neuronal cell cultures illustrate a distinct difference in the way that pyrethroids modify ion conductance and subsequent neurotransmitter release under resting and depolarized conditions. Continued efforts utilizing recent new tools like automated patch-clamp systems and MEAs to assess the effects of pyrethroids on the kinetics and voltage-dependent gating of ion channels in primary cultures or transfected cells is likely to provide new insight into the neurotoxicity of pyrethroids [79, 82]. 

Brown AM, Birnbauemr L. 1988. Direct G protein gating of ion channels. Am J Physiol 254 H401-H410. 

Keynes RD 1994 The kinetics of voltage-gated ion channels. Q Rev Biophys 27 339—434 Keynes RD, Elinder F 1999 The screw-helical voltage gating of ion channels. Proc R Soc Lond B... 

Figure 13.23 A model for voltage gating of ion channels. The voltage sensing paddles lie in the "down" position below the closed channel (left). Membrane depolarization pulls these paddles through the membrane. The motion pulls the base of the channel apart, opening the channel (right).

Horn, R. 2000. Conversation between voltage sensors and gates of ion channels. Biochemistry 39 1 5653-1 56 8. 

A subset of ion channels not gated by traditional neurotransmitters represents another receptor class. These iaclude potassium, calcium, sodium, and cychc adenosiae monophosphate (cAMP)-gated channels (14—16) for which a large number of synthetic molecules exist that alter ceUular function. 

The actions of toxins may be classified according to the our current perspective of ion channel function. Channels open, or gate , in response to a range of stimuli , variables that perturb the population distribution among a set of possible channel... 

Many of these materials form voltage-gated transmembrane ion channels, i.e. they exhibit non-linear current voltage curves, unlike the polyene antibiotics and gramicidin A which have linear current voltage curves. Of the peptaibol antibiotics the most thoroughly investigated substance to date is alamethicin 201 203>. 

Voltage-dependent gating requires voltage-dependent conformational changes in the protein component(s) of ion channels 100 Pharmacological agents acting on ion channels help define their functions 101... 

There are many other kinds of ion channels with different structural backbones and topologies. The channels used in the action potential contrast with those generating slow potentials at synapses and sensory receptors by having strongly voltage-dependent gating. The other... 

The GABA-gated chloride ion channel is modulated by several classes of drugs that bind to allosteric sites on the receptor complex the benzodiazepines, barbiturates and related intravenous general anesthetics such as etomidate and propofol, as well as anesthetic steroids and endogenous neurosteroids. It appears that some types of GABAa receptor are directly enhanced by ethanol and volatile general anesthetics (Fig. 16-2) [7,8,20]. 

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