A PATCH-CLAMP STUDY OF A GLUTAMATERGIC CHLORIDE CHANNEL ON PHARYNGEALMUSCLE OF THE NEMATODE ASCARIS-SUUM

Glutamatergic chloride channels on the pharyngeal muscle of Ascaris su um could be activated with glutamate and ivermectin and reversibly blo cked with picrotoxin using the patch clamp technique. No activation wa s observed with GABA, glycine and acetylcholine. Most of the current w as carried by the main subconductance state of 21 pS. Two smaller subc onductance 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 fr om other glutamatergic chloride channels reported from various animals . (C) 1997 Elsevier Science Ireland Ltd.