Article date: 1991/2/25
PubMed ID: 1712308
Journal name: European journal of pharmacology (ISSN: 0014-2999)
Radioligand binding studies indicate that p-isothiocyanato-t-butylbicycloorthobenzoate (p-NCS-TBOB) specifically acylates GABA-gated chloride channels. Preincubation of synaptoneurosomes with p-NCS-TBOB followed by washing resulted in a concentration dependent (63-500 nM) inhibition of both muscimol-stimulated chloride uptake and t-butylbicyclophosphorothionate (TBPS) binding. The extent of acylation (assessed by inhibition of [35S]TBPS binding) was highly correlated (r = 0.89; p less than 0.001) with the inhibition of muscimol-stimulated Cl- uptake. Neither basal Cl- uptake nor [3H]muscimol binding to GABAA receptors were affected by p-NCS-TBOB. Preincubation with the nonacylating 'cage' convulsant t-butylbicycloorthobenzoate (500 nM) followed by washing had no effect on either muscimol-stimulated Cl- uptake or [35S]TBPS binding. These findings indicate that p-NCS-TBOB interferes with the efficacy of muscimol promoted channel openings, but does not affect the recognition qualities of GABAA receptors. p-NCS-TBOB should prove useful in electrophysiological and biochemical studies examining the properties of GABA-gated Cl- channels.
Author List: Moody E J, Lewin A H, de Costa B R, Rice K C, Skolnick P
Publication Types: Journal Article; Research Support, Non-U.S. Gov't
Substances mentioned in the article: Bridged Bicyclo Compounds; Bridged Bicyclo Compounds, Heterocyclic; Chloride Channels; Chlorides; Ion Channels; Ligands; Membrane Proteins; Receptors, GABA-A; 4-(t-butyl)-1-(4-isothiocyanatophenyl)-2,6,7-trioxabicyclo(2.2.2)octane; Muscimol; gamma-Aminobutyric Acid;
Mesh terms: Acylation; Animals; Biological Transport, Active; Bridged Bicyclo Compounds/pharmacology; Bridged Bicyclo Compounds, Heterocyclic; Chloride Channels; Chlorides/metabolism; In Vitro Techniques; Ion Channels/drug effects; Ligands; Male; Membrane Proteins/metabolism; Muscimol/metabolism; Radioligand Assay; Rats; Rats, Inbred Strains; Receptors, GABA-A/drug effects; Synaptosomes/drug effects; gamma-Aminobutyric Acid/metabolism;