Article date: 1987/11/9
PubMed ID: 2444852
Journal name: Life sciences (ISSN: 0024-3205)
The effects of four tremorgenic and one nontremorgenic mycotoxins were studied on gamma-aminobutyric acid (GABAA) receptor binding and function in rat brain and on binding of a voltage-operated Cl- channel in Torpedo electric organ. None of the mycotoxins had significant effect on [3H]muscimol or [3H]flunitrazepam binding to the GABAA receptor. However, only the four tremorgenic mycotoxins inhibited GABA-induced 36Cl- influx and [35S] t-butylbicyclophosphorothionate [( 35S]TBPS) binding in rat brain membranes, while the nontremorgenic verruculotoxin had no effect. Inhibition of [35S]TBPS binding by paspalinine was non-competitive. This suggests that tremorgenic mycotoxins inhibit GABAA receptor function by binding close to the receptor's Cl- channel. On the voltage-operated Cl- channel, only high concentrations of verruculogen and verruculotoxin caused significant inhibition of the channel's binding of [35S]TBPS. The data suggest that the tremorgenic action of these mycotoxins may be due in part to their inhibition of GABAA receptor function.
Author List: Gant D B, Cole R J, Valdes J J, Eldefrawi M E, Eldefrawi A T
Publication Types: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.
Substances mentioned in the article: Bridged Bicyclo Compounds; Bridged Bicyclo Compounds, Heterocyclic; Chlorides; Ion Channels; Mycotoxins; Receptors, GABA-A; Muscimol; Flunitrazepam; tert-butylbicyclophosphorothionate;
Mesh terms: Animals; Brain/drug effects; Bridged Bicyclo Compounds/metabolism; Bridged Bicyclo Compounds, Heterocyclic; Chlorides/metabolism; Electric Organ/metabolism; Flunitrazepam/metabolism; In Vitro Techniques; Ion Channels/metabolism; Male; Muscimol/metabolism; Mycotoxins/pharmacology; Rats; Rats, Inbred Strains; Receptors, GABA-A/drug effects; Torpedo; Tremor/chemically induced;