BACKGROUND AND PURPOSE Striatal spiny neurons are selectively vulnerable to ischemia, but the ionic mechanisms underlying this selective vulnerability are unclear. Although a possible involvement of sodium and calcium ions has been postulated in the ischemia-induced damage of rat striatal neurons, the ischemia-induced ionic changes have never been analyzed in this neuronal subtype. METHODS We...

OBJECTIVES To evaluate the cerebral blood flow thresholds for membrane depolarization and repolarization and the effect of brain hypothermia on the cerebral blood flow threshold for membrane repolarization. DESIGN Prospective animal study. SETTING Experimental laboratory in a university hospital. SUBJECTS Male Sprague-Dawley rats (n = 40). INTERVENTIONS Cerebral blood flow and membrane ...

Amaç: Akut akustik travmaya ba¤l› tinnitus tedavisinde kullan›lan medikal tedavi yöntemlerinin etkinli¤i de¤erlendirildi. Hastalar ve Yöntem: Ateflli silah kullan›m› sonucu oluflan akut akustik travmaya ba¤l› olarak tinnitus geliflen 108 ordu mensubu (tümü erkek; ort. yafl 22; da¤›l›m 18-31) prospektif olarak çal›flmaya al›nd›. Altm›fl bir hastada sol, dokuz hastada sa¤ kulak tutulumu; 38 hasta...

Biophysical properties of neurons contributing to the ability of an animal to decide whether or not to respond were examined. B31/B32, two pairs of bilaterally symmetrical Aplysia neurons, are major participants in deciding to initiate a buccal motor program, the neural correlate of a consummatory feeding response. B31/B32 respond to an adequate stimulus after a delay, during which time additio...

A double ventricular response resulting from a single atrial depolarization conducting down dual atrioventricular (AV) nodal pathways has been pt^viously well characterized.' "̂ However, a double atrial response as a result of a single ventricular depolarization conducting across dual retrograde AV nodal pathways has not been well described.^'' This case report describes a patient in whom a sing...

We tested the hypothesis that eccentric contractions activate mechanosensitive or stretch-activated ion channels (SAC) in skeletal muscles, producing increased cation conductance. Resting membrane potentials and contractile function were measured in rat tibialis anterior muscles after single or multiple exposures to a series of eccentric contractions. Each exposure produced a significant and pr...

The effect of depolarization on the duration of the action potential was studied in short cardiac Purkinje fibers. Membrane potential was altered by overdriving pacemaker fibers showing spontaneous diastolic depolarization (dog), by injecting constantcurrent pulses through an intracellular microelectrode (sheep), or by voltage clamping (dog). Test action potentials were elicited at the end of 5...

Retinal amacrine cells are depolarized by the excitatory synaptic input from bipolar cells. When a graded depolarization exceeds the threshold level, trains of action potentials are generated. There have been several reports that both spikes and graded depolarization are sensitive to tetrodotoxin (TTX). In the present study, we investigated the contribution of voltage-gated currents to membrane...

The effect of depolarization on the duration of the action potential was studied in short cardiac Purkinje fibers. Membrane potential was altered by overdriving pacemaker fibers showing spontaneous diastolic depolarization (dog), by injecting constantcurrent pulses through an intracellular microelectrode (sheep), or by voltage clamping (dog). Test action potentials were elicited at the end of 5...