Jp. Dilger et al., INTERACTIONS OF GENERAL-ANESTHETICS WITH SINGLE ACETYLCHOLINE-RECEPTOR CHANNELS, European journal of anaesthesiology, 12(1), 1995, pp. 31-39
We used single-channel recording techniques to study the effects of ge
neral anaesthetics on nicotinic acetylcholine receptor channels. Norma
lly, these channels remain open for a few milliseconds. Anaesthetics i
nduce three different patterns of channel activity. Ether causes the c
hannel amplitude to be smaller and noisier than normal; isoflurane ind
uces a flickery pattern in which openings occur in bursts of brief ope
nings; propofol causes the channels to appear as isolated brief openin
gs. These patterns can all be understood in terms of a model in which
the anaesthetics bind directly to the channel protein and interrupt th
e flow of ions through the channel. The difference in pattern is deter
mined by the duration of anaesthetic binding. Ether remains bound for
the shortest period (less-than-or-equal-to 0.01 ms), followed by isofl
urane (0.5 ms) and propofol (greater-than-or-equal-to 2 ms). The anaes
thetics may either be physically obstructing the pore of the channel o
r acting allosterically by inducing a new, non-conducting conformation
of the channel.