Molecular actions of pentobarbitone on sodium channels in lipid bilayers: Role of channel structure Academic Article uri icon

Overview

MeSH Major

  • Electrophorus
  • Lipid Bilayers
  • Pentobarbital
  • Sodium Channels

abstract

  • The molecular mechanisms by which anaesthetics interfere with neuronal function are controversial. We have examined the effects of pentobarbitone on muscle-derived (eel electroplax) sodium channels incorporated into planar bilayers under exactly the same experimental conditions that we used previously to study the anaesthetic modification of human brain channels. This technique allows examination of protein-mediated similarities and differences. Sodium channels from the electroplax (muscle-derived) of the electric eel were purified and reconstituted into planar lipid bilayers containing 4:1 phosphatidylethanolamine:phosphatidylcholine in the presence of batrachotoxin, a sodium channel activator. Pentobarbitone had similar voltage-independent blocking effects on sodium channels from eel electroplax and human brain, as demonstrated by similar dose-response curves (IC50 = 613 mumol litre-1). However, activation of sodium channels from eel electroplax, in contrast with human brain, was relatively insensitive to the concentration of pentobarbitone. The only significant effect was a -5.8-mV shift in the activation midpoint with pentobarbitone 680 mumol litre-1. Therefore, differences in primary structures played no role in the observed voltage-independent block of channels by pentobarbitone, whereas subunits or other structural differences between sodium channels from eel electroplax and human brain must be responsible for the minimal effect of pentobarbitone on activation of muscle-derived sodium channels.

publication date

  • June 22, 1994

Research

keywords

  • Academic Article

Identity

Language

  • eng

PubMed ID

  • 8024914

Additional Document Info

start page

  • 668

end page

  • 73

volume

  • 72

number

  • 6