Friedman R N, Bittner G D, Blundon J A
Department of Zoology, University of Texas, Austin.
J Pharmacol Exp Ther. 1988 Jul;246(1):125-31.
The effects of EtOH on the crayfish Procambarus clarkii and P. simulans were examined behaviorally in vivo and electrophysiologically in vitro on pre- and postjunctional mechanisms of synaptic plasticity at opener excitor nerve-muscle junctions. Addition of 75 mM EtOH to the bath water of holding tanks produced 47 to 54 mM EtOH levels in the hemolymph (blood) within 24 hr. These hemolymph EtOH levels were maintained for weeks by daily changes of the bath water containing 75 mM EtOH. After 24 hr of exposure to 75 to 150 mM EtOH in vivo, crayfish showed behavioral signs of intoxication as measured by a significant increase in righting reflex times and a significant decrease in tail-flip escape behavior. After 2 weeks of chronic exposure to 75 mM EtOH, crayfish showed behavioral tolerance as measured by a decrease in righting time and an increase in tail-flip escape behavior to control levels. EtOH applied acutely to opener nerve-muscle preparations in vitro at 10 to 100 mM concentrations produced an increased probability of transmitter release as measured by an increased frequency of spontaneous release of transmitter quanta and an increased amplitude of facilitated synaptic potentials evoked by 10 to 40 Hz stimulation of the excitor axon. Acute application of 300 to 600 mM EtOH resulted in a decreased amplitude of facilitated synaptic potentials due primarily to a decrease in postsynaptic input resistance. These data suggest that EtOH has a concentration-dependent biphasic effect on synaptic transmission.
研究了乙醇对克氏原螯虾和拟鳄龟的影响，采用行为学方法在体内进行研究，并通过电生理学方法在体外对 opener 兴奋性神经 - 肌肉接头处突触可塑性的突触前和突触后机制进行研究。在饲养水箱的浴水中添加 75 mM 乙醇，24 小时内血淋巴（血液）中的乙醇水平达到 47 至 54 mM。通过每天更换含有 75 mM 乙醇的浴水，这些血淋巴乙醇水平可维持数周。在体内暴露于 75 至 150 mM 乙醇 24 小时后，小龙虾表现出中毒的行为迹象，通过翻正反射时间显著增加和尾部翻转逃避行为显著减少来衡量。在慢性暴露于 75 mM 乙醇 2 周后，小龙虾表现出行为耐受性，通过翻正时间减少和尾部翻转逃避行为增加至对照水平来衡量。在体外以 10 至 100 mM 的浓度急性应用乙醇于 opener 神经 - 肌肉制剂，通过递质自发释放量子频率增加和 10 至 40 Hz 刺激兴奋性轴突诱发的易化突触电位幅度增加来衡量，导致递质释放概率增加。急性应用 300 至 600 mM 乙醇导致易化突触电位幅度降低，主要是由于突触后输入电阻降低。这些数据表明乙醇对突触传递具有浓度依赖性的双相作用。
