Article date: 1992/10/1
PubMed ID: 1279355
Journal name: Brain research. Molecular brain research (ISSN: 0169-328X)
Membrane currents were recorded from Xenopus laevis oocytes injected with C. elegans poly(A)+ RNA. In such oocytes glutamate activated an inward membrane current that desensitized in the continued presence of glutamate. Glutamate-receptor agonists quisqualate, kainate, and N-methyl-D-aspartate were inactive. The reversal potential of the glutamate-sensitive current was -22 mV, and exhibited a strong dependence on external chloride with a 48 mV change for a 10-fold change in chloride. The chloride channel blockers flufenamate and picrotoxin inhibited the glutamate-sensitive current. Ibotenate, a structural analog of glutamate, also activated a picrotoxin-sensitive chloride current. Ibotenate was inactive when current was partially desensitized with glutamate, and the responses to low concentrations of glutamate and ibotenate were additive. The anthelmintic/insecticide compound avermectin directly activated the glutamate-sensitive current. In addition, avermectin increased the response to submaximal concentrations of glutamate, shifted the glutamate concentration-response curve to lower concentrations, and slowed the desensitization of glutamate-sensitive current. We propose that the glutamate-sensitive chloride current and the avermectin-sensitive chloride current are mediated via the same channel.
Author List: Arena J P, Liu K K, Paress P S, Schaeffer J M, Cully D F
Publication Types: Journal Article
Substances mentioned in the article: Anthelmintics; Chloride Channels; Chlorides; Glutamates; Membrane Proteins; Poly A; Ibotenic Acid; Glutamic Acid; RNA; Ivermectin; avermectin;
Mesh terms: Animals; Anthelmintics/pharmacology; Caenorhabditis elegans/drug effects; Cell Membrane Permeability/drug effects; Chloride Channels; Chlorides; Glutamates/pharmacology; Glutamic Acid; Ibotenic Acid/pharmacology; Ion Channel Gating/drug effects; Ivermectin/analogs & derivatives; Membrane Proteins/drug effects; Microinjections; Oocytes/drug effects; Poly A/genetics; RNA/genetics; Xenopus laevis;