Saturable binding of /sup 35/S-t-butylbicyclophosphorothionate to the sites linked to the GABA receptor and the interaction with gabaergic agents

Journal Article · Mon Feb 27 04:00:00 EST 1984 · Life Sci.; (United States)

DOI:https://doi.org/10.1016/0024-3205(84)90202-9· OSTI ID:6267121

Wong, D T; Threlkeld, P G; Bymaster, F P; Squires, R F

/sup 35/-S-t-Butylbicyclophosphorothionate (/sup 35/S-TBPS) binds in a concentration-saturable manner to specific sites on membranes from rat cerebral cortex. Using a filtration assay at 25/sup 0/C, in 250 mM NaCl, specific binding of /sup 35/S-TBPS constitutes about 84 to 94 percent of total binding, depending on radioligand concentrations. /sup 35/S-TBPS binding is optimal in the presence of NaCl or NaBr and substantially less in the presence of NaI or NaF. It is sensitive to the treatment with 0.05 percent Triton X-100 but not to repeated freezing and thawing, procedures which increase /sup 3/H-GABA binding. Pharmacological studies show that /sup 35/S-TBPS binding is strongly inhibited by GABA-A receptor agonists (e.g., GABA and muscimol) and by the noncompetitive antagonist, picrotoxin, but not the competitive antagonist, bicuculline. Compounds which enhance binding of radioactive GABA and benzodiazepines, such as the pyrazolopyridines, cartazolate and trazolate, and a diaryl-triazine, LY81067, are also potent inhibitors of /sup 35/S-TBPS binding, with LY81067 being the most effective. The effects of GABA, picrotoxin

• Research Organization: Eli Lilly and Co., Indianapolis, IN
• OSTI ID: 6267121
• Journal Information: Life Sci.; (United States), Journal Name: Life Sci.; (United States) Vol. 34:9; ISSN LIFSA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES