Voltage-clamp experiments on isolated giant axons of the cockroach Periplaneta americana L. show that chemically synthesized saxitoxin specifically and reversibly blocks the transient inward sodium current without affecting the steady-state outward potassium current. From the concentration depending of sodium current suppression it is concluded that individual sodium channels are blocked by sin...

In this issue of Molecular Pharmacology (p. 665), Pannacione et al. provide evidence of a role for the voltage-gated potassium channel alpha subunit Kv3.4 and its ancillary subunit MiRP2 in beta-amyloid (Abeta) peptide-mediated neuronal death. The MiRP2-Kv3.4 channel complex-previously found to be important in skeletal myocyte physiology-is now argued to be a molecular correlate of the transien...

AIMS The human cardiac transient outward K(+) current I(to) (encoded by Kv4.3 or KCND3) plays an important role in phase 1 rapid repolarization of cardiac action potentials in the heart. However, modulation of I(to) by intracellular signal transduction is not fully understood. The present study was therefore designed to determine whether/how human atrial I(to) and hKv4.3 channels stably express...

Neuromodulatory effects can vary with their mode of transmission. Phasic release produces local and transient increases in dopamine (DA) up to micromolar concentrations. Additionally, since DA is released from open synapses and reuptake mechanisms are not nearby, tonic nanomolar DA exists in the extracellular space. Do phasic and tonic transmissions similarly regulate voltage-dependent ionic co...

The present review deals with Ca2+-independent, K+-carried transient outward current (Ito), an important determinant of the early repolarization phase of the myocardial action potential. The density of total Ito and of its fast and slow components (I(to,f) and I(to,s), respectively), as well as the expression of their molecular correlates (pore-forming protein isoforms Kv4.3/4.2 and Kv1.4, resp...

1. Whole-cell voltage-clamp techniques were used to record K+ currents in relay neurons (RNs) that had been acutely isolated from rat thalamic ventrobasal complex and maintained at 23 degrees C in vitro. Tetrodoxin (TTX; 0.5 microM) was used to block Na+ currents, and reduced extracellular levels of Ca2+ (1 mM) were used to minimize contributions from Ca2+ current (ICa). 2. In RNs, depolarizing...