The effects of two anesthetic ethers methoxyflurane and diethyl ether (ether), and one convulsant ether, fluothyl, were examined on miniature end-plate currents and on end-plate current fluctuations at the frog neuromuscular junction. Either methoxyflurane or fluothyl was found to reduce the amplitude and the half-decay time of the miniature end-plate currents. When the concentration of methoxyflurane was raised from 10-4 to 5.10-4 M its effect on the miniature end-plate current amplitude was increased but that on the half-decay time remained unaltered. The effect of ether on the miniature end-plate current was dose-dependent: at 10-3 M it reduced the half-decay time without affecting the amplitude, whereas at 10-2 M it increased the half-decay time and decreased the amplitude. Analysis of end-plate current fluctuations revealed that the effects of methoxyflurane (5.10-4 M) and ether (10-2 M) on the mean conductance and open-time of the acetylcholine receptor channels were comparable to their effects on the amplitude and the half-decay time of the miniature end-plate current. It is concluded that the effect of such structurally 'non-specific' drugs comprises a combination of discrete and distinguishable events which are specific and dose-dependent for each of the agents used.
|Number of pages||9|
|State||Published - 1979|