Retinal bipolar cells are slow potential neurons that respond to photoreceptor inputs with graded potentials and do not fire action potentials. We found that transient ON bipolar cells recorded in retinal slices possess voltage-gated sodium channels located on either their dendrites or somas. The sodium currents in these neurons did not generate spikes but enhanced voltage responses evoked by v...

Strychnine blocks sodium conductance in the frog node of Ranvier. This block was studied by reducing and slowing sodium inactivation with scorpion venom. The block is voltage and time dependent. The more positive the axoplasm the greater the block and the faster the approach to equilibrium. Some evidence is presented suggesting that only open channels can be blocked. The block is reduced by rai...

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...

Experiments were undertaken to verify the existence of fast sodium channels in the adrenal chromaffin cell membrane and to assess their contribution to the physiological release of catecholamines. We have used veratridine to activate sodium channels. Veratridine causes secretion of catecholamines from perfused cat adrenal gland. Secretory response to veratridine is calcium dependent and abolish...

tetrodotoxin binding activity and a protein of ‫072ف‬ kDa (Agnew et al., 1980). Subsequent purification studies showed that the sodium channel from mammalian brain is a complex of ␣ al., 1982), the tetrodotoxin-binding component of the sodium channel purified from eel electroplax is a single Voltage-gated sodium channels are responsible for the protein of 270 kDa (Miller et al., 1983), and the ...