A patch clamp study of a glutamatergic chloride channel on pharyngeal muscle of the nematode Ascaris suum.

Glutamatergic chloride channels on the pharyngeal muscle of Ascaris suum could be activated with glutamate and ivermectin and reversibly blocked with picrotoxin using the patch clamp technique. No activation was observed with GABA, glycine and acetylcholine. Most of the current was carried by the main subconductance state of 21 pS. Two smaller subconductance states occurred rarely. Open time histograms could be best fitted by two time constants of tau(o1) = 0.33 ms and tau(o2) = 9.8 ms present at all glutamate concentrations applied. The results suggest that some properties of the channel investigated here are different from other glutamatergic chloride channels reported from various animals.