Electrical stimulation of isolated adult rat heart cells in suspension at 4 Hz resulted in a fourfold increase in the rate of sodium influx and efflux across the sarcolemma, with no change in total cell sodium, as measured with 22Na. The magnitude of stimulation-dependent sodium fluxes under these conditions averaged 17 nmol/min/mg protein. The increased rate of efflux was inhibited by tetrodot...

1. Amino acids, particularly glutamate, gamma-aminobutyrate, aspartate and glycine, were released from rat brain slices on incubation with protoveratrine (especially in a Ca(2+)-deficient medium) or with ouabain or in the absence of glucose. Release was partially or wholly suppressed by tetrodotoxin. 2. Tetrodotoxin did not affect the release of glutamine under various incubation conditions, no...

The X-ray structure of the bacterial sodium channel NavAb provides a new template for the study of sodium and calcium channels. Unlike potassium channels, NavAb contains P2 helices in the outer-pore region. Because the sequence similarity between eukaryotic and prokaryotic sodium channels in this region is poor, the structural similarity is unclear. We analyzed it by using experimental data on ...

BACKGROUND Multiple voltage-dependent sodium channels (Na(v)) contribute to action potentials and excitability of primary nociceptive neurons. The aim of the current study was to characterize subtypes of Na(v) that contribute to action potential generation in peripheral unmyelinated human C-type nerve fibers. METHODS Registration of C-fiber compound action potentials and determination of memb...