Voltage-dependent sodium and potassium channels in mammalian cultured Schwann cells.
AUTOR(ES)
Shrager, P
RESUMO
Cultured Schwann cells from sciatic nerves of newborn rabbits and rats have been examined with patch-clamp techniques. In rabbit cells, single sodium and potassium channels have been detected with single channel conductances of 20 pS and 19 pS, respectively. Single sodium channels have a reversal potential within 15 mV of ENa, are blocked by tetrodotoxin, and have rapid and voltage-independent inactivation kinetics. Single potassium channels show current reversal close to EK and are blocked by 4-aminopyridine. From these results, and from comparisons of single-channel and whole-cell data, we show that these Schwann cells contain voltage-dependent sodium and potassium channels that are similar in most respects to the corresponding channels in mammalian axonal membranes. Cultured rat Schwann cells also have sodium channels, but at a density about 1/10th that of rabbit cells, a result in agreement with saxitoxin binding experiments on axon-free sectioned nerves. Saxitoxin binding to cultured cells suggests that there are up to 25,000 sodium channels in a single rabbit Schwann cell. We speculate that in vivo Schwann cells in myelinated axons might act as a local source for sodium channels at the nodal axolemma.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=397165Documentos Relacionados
- Voltage-dependent potassium channels in mouse Schwann cells.
- Voltage-dependent calcium and potassium channels in Schwann cells cultured from dorsal root ganglia of the mouse.
- Voltage-dependent potassium channels in activated rat microglia.
- Single voltage-dependent potassium channels in rat peripheral nerve membrane.
- Voltage-dependent sodium channels develop in rat retinal pigment epithelium cells in culture.
