Effects of Methylglyoxal on Central and Peripheral Cholinergic Responses

Methylglyoxal (MG) has been shown to have a depolarizing effect on the giant interneurones of the isolated 6th abdominal ganglion of the cockroach. This effect of MG was inhibited by concentrations of nicotine, dtubocurarine and physostigmine which blocked transmission at the cholinergic cereal nerve-giant interneurone synapse. MG (5 × 10−5 to 5 × 10−4 M) produced concentration-dependent contractures of the isolated frog rectus abdominis muscle which were inhibited by d-tubocurarine (10−4 M) and physostigmine (10−6 M). MG enhanced the action of acetylcholine and inhibited KCl-evoked contractures whereas it had no effect on the response to carbachol. It is concluded that MG appears to act as a cholinomimetic in both the peripheral and central nervous systems.