Potassium channels properties

Kv 3 -subunits are auxiliary subunits of Shaker-related Kv-channels, which belong to the Kvl subfamily of voltage-gated potassium channels. Kv(3 -subunits may function as chaperones in Kva -subunit assembly and may modulate the gating properties of Kv-channels. In particular, some Kv(3 -subunits may confer a rapid inactivation to otherwise non-inactivating Kv-channels. 

The N-acetyl procainamide (NAPA) metabolite blocks rapid potassium channels. cHas p-blocking properties. 

Noskov, S.Y. Berneche, S. Roux, B., Control of ion selectivity in potassium channels by electrostatic and dynamic properties of carbonyl ligands, Nature 2001,431, 830-834. 

Nelson MT, Quayle JM 1995 Physiological roles and properties of potassium channels in arterial smooth muscle. Am J Physiol 268 C799—C822... 

A structurally novel series of substituted 10//-benzo[4,5]furo[3,2- ]indole-l-carboxylic acids 504-507 was prepared and shown to possess potent, bladder-selective smooth muscle relaxant properties and thus is potentially useful for the treatment of urge urinary incontinence. Electrophysiological studies using rat detrusor myocytes have demonstrated that prototype compound 8 produces a significant increase in hyperpolarizing current, which is iberiotoxin (IbTx)-reversed, thus consistent with activation of the large-conductance Ca -activated potassium channel (BKca) <2001BML2093>. 

It is an alkaloid obtained from the bark of cinchona and is a dextro isomer of anti-malarial drug quinine. Its sodium channel blocking property results in an increased threshold for excitability and decreased automaticity. As a consequence of its potassium channel blocking properties, it prolongs action potential in most cardiac cells. 

T lymphocyte Kvl.3 potassium channels were also inhibited by genistein (42) in a protein tyrosine kinase (PTK)-independent way [290]. Daidzein (40) that was also studied in this work did not influence the properties of Kvl.3 potassium channels. The genistein-induced inhibition occurred much faster than was observed for neuronal Kvl.3 channels expressed in HEK293 cells [291], for which a PTK-dependent mechanism of genistein (42) action was proposed. On the other hand, PTK-independent inhibition of myocyte Kvl.3 channels by genistein (42) was reported by Washizuka et al. [292]. 

Wei J, Yang IC, Tapper AR, Murray KT, Viswanathan P, Rudy Y, Bennett PB, Norris K, Balser JR, Roden DM, George AL. KCNE1 polymorphism confers risk of drug-induced long QT syndrome by altering kinetic properties of IKs potassium channels. Circulation 1999 1 495. 

The role of calcium in regulating cardiovascular physiology is presented in the fourth section of this volume. House et al. have provided an excellent review on the structure of calmodulin-dependent protein kinase II and its role in the contractility as well as proliferation and migration of VSMC. Banderali et al. have examined in detail the cellular regulation and pharmacological properties of calcium-activated potassium channels and their role in control of vascular tone by endothelium. 

Peretz A, Degani N, Nachman R et al. (2005) Meclofenamic acid and diclofenac, novel templates of KCNQ2/Q3 potassium channel openers, depress cortical neuron activity and exhibit anticonvulsant properties. Mol Pharmacol 67 1053-1066... 

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