Effect of ethanol on the maturation of the spontaneous transmitter release by regenerated nerve endings.

The cellular mechanisms involved in the theratogentic action of ethanol are not well known, but neuron outgrowth and synaptogenesis are regarded as the periods in which ethanol causes its major damage in the nervous system. The effects of chronic treatment with ethanol on the maturation of the spontaneous transmitter release by regenerated nerve endings in the rat were studied. The sciatic nerve was crushed and miniature end plate potentials (mepps) were recorded intracellularly in the re-innervated extensor digitorum longus muscle at different points in time after denervation; end plate potentials (epps) were also recorded. Two main effects were observed in the re-innervated muscles of ethanol-treated rats: (1) the appearance of spontaneous and evoked transmitter release was delayed and (2) the subsequent increase in frequency of mepps is faster. The possible mechanisms involved in these effects are discussed.