Single glutamate gated channels in insect visceral muscle.

Single glutamate-gated ion channels with a conductance of 135 pS are demonstrated in tonic muscle fibres of the locust hindgut. Channel kinetics closely resemble those of glutamatergic channels in locust skeletal muscles. Glutamate concentrations increasing within the range from 5 X 10(-5) to 1 X 10(-3) M result in an increase of the frequency of channel opening and a decrease in channel closed times. Delta-philanthotoxin, a toxin isolated from the venom of the digger wasp Philanthus triangulum, inhibits channel activity by blocking open channels and increasing channel closed times.