Voltage-dependent membrane currents were investigated in enzymatically dissociated photoreceptors of Lima scabra using the whole-cell clamp technique. Depolarizing steps to voltages more positive than -10 mV elicit a transient inward current followed by a delayed, sustained outward current. The outward current is insensitive to replacement of a large fraction of extracellular Cl- with the imper...

In hair cells dissected from the frog crista ampullaris, the combination of a calcium-dependent (IKCa) and a purely voltage-dependent component (IKV) gives rise to the delayed potassium current complex (IKD). These currents have been recently reported to display slow depolarization-induced inactivation and biphasic inactivation removal by hyperpolarization. The amplitude and inactivation kineti...

BACKGROUND Propofol is widely used clinically for the induction and maintenance of anesthesia. Clinical case reports have shown that propofol has an antiatrial tachycardia/fibrillation effect; however, the related ionic mechanisms are not fully understood. The current study investigates the effects of propofol on human cardiac potassium channels. METHODS The whole cell patch voltage clamp tec...

The effects of valinomycin and nigericin on sugar chemotaxis in Spirochaeta aurantia were investigated by using a quantitative capillary assay, and the fluorescent cation, 3,3'-dipropyl-2,2'-thiodicarbocyanine iodide was used as a probe to study effects of chemoattractants on membrane potential. Addition of a chemoattractant, D-xylose, to cells in either potassium or sodium phosphate buffer res...

A transient, dose-dependent cardiac depression was produced by defibrillator shocks in an isolated, working canine heart preparation perfused with oxygenated arterial blood from a support dog. Accompanying this depression was an efflux of potassium (K+), forced out of the myocardial cells by the passage of defibrillating current. The transient increase in extracellular K+ concentration was reco...

Intradendritic recordings in Purkinje cells from a defined area in parasaggital slices of cerebellar lobule HVI, obtained after rabbits were given either paired (classical conditioning) or explicitly unpaired (control) presentations of tone and periorbital electrical stimulation, were used to assess the nature and duration of conditioning-specific changes in Purkinje cell dendritic membrane exc...

The principal cells of the chick tangential nucleus are second-order sensory neurons that participate in the three-neuron vestibulo-ocular and vestibulocollic reflexes. In postnatal animals, second-order vestibular neurons fire repetitively on depolarization. Previous studies have shown that, although this is an important feature for normal reflex function, it is only acquired gradually during ...

To gain insight into the molecular basis of cardiac repolarization, we have expressed K' channels cloned from ventricular myocardium in Xenopus oocytes. A recently identified human cardiac K' channel isoform (human Kvl.4) has properties similar to the 4-aminopyridine-sensitive calcium-insensitive component of the cardiac transient outward current. However, these channels recovered from inactiva...

We investigated, using a computational model, the biophysical correlates of measured discharge patterns of lateral superior olive (LSO) neuron responses to monaural and binaural stimuli. The model's geometry was based on morphological data, and static electric properties of the model agree with available intracellular responses to hyperpolarizing current pulses. Inhibitory synapses were located...