Article date: 1991/1/1
PubMed ID: 1659677
Journal name: Neurotoxicology (ISSN: 0161-813X)
Addition of EDTA (0.5-10 mM) to rat brain synaptoneurosomes stimulated rapid, concentration-dependent uptake of 36C1-. Chloride uptake stimulated by EDTA was additive with the 36C1- uptake induced by the GABAA agonist, muscimol, and was not blocked by the GABA-antagonist, picrotoxin, the glycine antagonist, strychnine or the loop diuretic, furosemide. However, the chloride transport inhibitor DIDS completely antagonized 36C1- uptake. EDTA-induced 36C1- uptake varied across brain regions as follows: Striatum greater than hippocampus greater than cerebellum greater than tectum greater than cerebral cortex greater than brain stem greater than hypothalamus. EDTA-induced 36C1- uptake was also present in liver tissues. EDTA analogues, EGTA and CDTA, also stimulated uptake. Although the effect of EDTA was dependent on the presence of extravesicular Ca2+ (0.01-10 mM) this action did not appear to be due to Ca2+ chelation since BAPTA, arsenazo III and citrate were ineffective. These results suggest that EDTA stimulates 36C1- uptake into brain synaptoneurosomes by a picrotoxin-insensitive, calcium-dependent mechanism that may involve a DIDS sensitive anion exchanger or ion channel.
Author List: Mathew J, Frye G D
Publication Types: Journal Article; Research Support, U.S. Gov't, P.H.S.
Substances mentioned in the article: Chelating Agents; Chloride Channels; Chlorides; Membrane Proteins; Radioisotopes; Muscimol; CDTA; Chlorine; Egtazic Acid; Edetic Acid; Calcium;
Mesh terms: Animals; Biological Transport/drug effects; Brain/drug effects; Calcium/metabolism; Chelating Agents/pharmacology; Chloride Channels; Chlorides/metabolism; Chlorine; Edetic Acid/analogs & derivatives; Egtazic Acid/pharmacology; Male; Membrane Proteins/drug effects; Muscimol/pharmacology; Radioisotopes; Rats; Rats, Inbred Strains; Synaptosomes/drug effects;