Mechanism of Spontaneous Recovery of Neuromuscular Transmission afterAcetylcholinesterase Inhibition in the Rat Neuromuscular Junction (Onderzoek naar het Herstelmechanisme van Neuromusculaire Transmisna Acetylcholinesterase Remming)

摘要

Neuromuscular transmission shows a significant degree of spontaneous recoveryafter being impeded by acetylcholinesterase inhibition. Part of the recovery can be ascribed to de novo synthesis of acetylcholinesterase but another part is independent of enzyme activity. To unravel the mechanism underlying the synaptic adaptation to acetylcholinesterase inhibition a study compared a number of electrophysiological parameters in diaphragms taken from animals that were sacrificed within 15 minutes after a 2xLD50 dose of the acetylcholinesterase inhibitor diisopropylfluorophosphate and from similarly treated animals killed after being kept alive for 3h under artificial respiration. The study found no differences in the quantal content. There was a significantly smaller degree of endplate potential rundown at tetanic stimulation and the mepp amplitude was smaller in the 3h adapted animals. In addition, the desensitization induced by carbachol appeared to be less in the group. It is concluded that postsynaptic changes may be involved in the spontaneous recovery of neuromuscular transmission after acetylcholinesterase inhibition.