The sodium current (I(Na)) that develops after step depolarization of a voltage clamped squid axon is preceded by a transient outward current that is closely associated with the opening of the activation gates of the Na pores. This "gating current" is best seen when permeant ions (Na and K) are replaced by relatively impermeant ones, and when the linear portion of capacitative current is elimin...

In the mammalian neocortex, an area typically receives inputs from, and projects to, dozens of other areas. Mechanisms are needed to flexibly route information to the right place at the right time, which we term 'pathway gating'. For instance, a region in your brain that receives signals from both visual and auditory pathways may want to 'gate in' the visual pathway while 'gating out' the audit...

The flow of ions through membrane channels is precisely regulated by gates. The architecture and function of these elements have been studied extensively, shedding light on the mechanisms underlying gating. Recent investigations have focused on ion occupancy of the channel's selectivity filter and its ability to alter gating, with most studies involving prokaryotic K+ channels. Some studies use...

ECG-based gating in cardiac MR imaging requires additional patient preparation time, is susceptible to RF and magnetic interference, and is ineffective in a significant percentage of patients. "Wireless" or "self-gating" techniques have been described using either interleaved central k-space lines or projection reconstruction to obtain MR signals synchronous with the cardiac cycle. However, the...

Cardiac phase determination of 3D ultrasound (US) imaging has numerous applications including intraand inter-modality registration of US volumes, and gating of live images. We have developed a novel and potentially clinically useful real-time three-dimensional (3D) cardiac motion gating technique that facilitates and supports 3D USguided procedures. 0ur proposed real-time 3D-Masked-PCA techniqu...

omega-conotoxin GVIA (omegaCTX) is a specific blocker of N-type calcium (CaV2.2) channels that inhibits neuropathic pain. While the toxin appears to be an open channel blocker, we show that N-channel gating charge movement is modulated. Gating currents were recorded from N-channels expressed along with beta2a and alpha2delta subunits in HEK293 cells in external solutions containing either lanth...

Recovery from inactivation of T-type Ca channels is slow and saturates at moderate hyperpolarizing voltage steps compared with Na channels. To explore this unique kinetic pattern we measured gating and ionic currents in two closely related isoforms of T-type Ca channels. Gating current recovers from inactivation much faster than ionic current, and recovery from inactivation is much more voltage...

Tracer ion flux measurements are a commonly used method for studying ion transport through membranes of cellular systems, where the rate of ion flow is determined by gating processes which control the opening and closing of transmembrane channels. Due to recent advances in the theoretical analysis of tracer flux from or into closed membrane structures (CMS), the mechanism of gating reactions ca...

Background An important requirement for successful cardiac MRI is accurate gating. However, obtaining proper Electrocardiogram (ECG) gating inside the MRI is a difficult problem, due to the Magneto-Hydro-Dynamic (MHD) effect, resulting in frequent intermittent gating. The MHD effect generates a voltage due to conductive blood flow perpendicular to B0, and distorts the real ECG. Intermittent gat...

REPLY To the Editor: We appreciate the comments of our distinguished colleagues and thank the editors of the Journal of Neurophysiology for the opportunity to reply. We agree with Jurisic and Bezanilla (2006) that simple, variable capacitance is properly written as differential capaci-tance. The problem is that even this time-varying capacitance must change instantaneously with each voltage cha...