Voltage-activated potassium channels

Timpe LC, Fantl WJ. Modulation of a voltage-activated potassium channel by peptide growth factor receptors. J Neurosci 1994 14 1195-1201. 

It is a POTASSIUM-CHANNEL BLOCKER and TOXIN/NEUROTOXIN. It blocks voltage-activated potassium channels (K,i 3, Kvi.2.4 current of the squid giant axon, and K, current of human lymphocytes). 

Inhibition of voltage operated potassium channels Activation of PLCp... 

Peukert S, Brendel J, Pirard B, Briiggemann A, Below P, Kleemann HW, Hem-merle H, Schmidt W. Identification, synthesis, and activity of novel blockers of the voltage-gated potassium channel Kvl.5. J Med Chem 2003 46 486-98. 

Retigabine is a novel anticonvulsant drug in development (Phase II). It activates voltage-gated potassium channels and also affects GABA neurotransmission in the GABAyi receptor. ... 

An inhibition of the voltage-dependent potassium channels located in presy-naptic terminals can be expected to lead to spike broadening, an increase in calcium influx, and facilitation of neurotransmitter release (19). Thus, one potential functional role for 5-HT4 receptors could be the facilitation of synaptic transmission in the CNS. Although evidence for such an effect remains equivocal in CNS neurons, activation of 5-HT4 receptors has been reported to increase synaptic transmission in the myenteric nervous system (20). Such an effect might contribute to the prokinetic activity of benzamide 5-HT4 receptor agonists in the gastrointestinal tract. 

Therapeutic uses Cocaine has a local anesthetic action that represents the only current rationale for the therapeutic use of cocaine-, cocaine is applied topically as a local anesthetic during eye, ear, nose, and throat surgery. While the local anesthetic action of cocaine is due to a block of voltage-activated sodium channels, an interaction with potassium channels may contribute to cocaine s ability to cause cardiac arrhythmias. [Note Cocaine is the only local anesthetic that causes vasoconstriction. This effect is responsible for the necrosis and perforation of the nasal septum seen in association with chronic inhalation of cocaine powder.]... 

Yusaf, S. P., Wray, D., and Sivaprasadarao, A. (1996). Measurement of the movement of the S4 segment during activation of a voltage-gated potassium channel. I flugers Arch. Eur. J. Physiol. 433, 91-97. 

The second class of channels are the voltage-dependent sodium channels, where histrionicotoxins reduce conductances in a manner reminiscent of local anesthetics (61). The third class are the voltage-dependent potassium channels, where histrionicotoxins reduce conductances in a time- and stimulus-dependent manner. Structure-activity relationships for histrionicotoxins differ at the three classes of channels (61). 

First, simple voltage-gated potassium channels seem to have no selective chemical activators, only blockers. 

Bekkers JM 2000 Distribution and activation of voltage-gated potassium channels in cell-attached and outside-out patches from large layer 5 cortical pyramidal neurons of the rat. J Physiol 525 611-620... 

Taschenberger H, Grantyn R (1998) Interaction of calcium-permeable non-A7-methyl-D-aspartate receptor channels with voltage-activated potassium and calcium currents in rat retinal ganglion cells in vitro. Neuroscience 84 877-896. 

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