Negative modulation of sodium channels in cultured chick muscle cells by the channel activator batrachotoxin.

摘要: We have investigated the possibility that cellular control of membrane excitability involves feedback mechanisms in which degree activity voltage-sensitive Na+ channels regulates number these channels. Using two independent assays, channel-mediated uptake and specific binding [3H] saxitoxin, we studied effects pharmacological activation with batrachotoxin (BTX) on properties Upon exposure cultured muscle cells to BTX (1 microM), surface decreases by approximately 75%, a half-time 3-6 h. This decrease is prevented blockade does not reflect changes apparent affinities towards either or saxitoxin. reduction reversible: gradual increase dependent protein synthesis observed upon removal activator. The BTX-induced associated an enhanced rate disappearance These findings point existence down-regulation mechanism for modulation under conditions elevated channel activity.