engleski

(3H)t-butylbicycloorthobenzoate binding to recombinant alpha1 beta2 gamma2s GABA-A receptor

The interaction of several selected compounds with the binding of the cage convulsant t-[H-3]butylbicycloorthobenzoate ([H-3]TBOB) to membranes isolated from human embryonic kidney HEK) 293 cells stably transfected with alpha (1) beta (2)gamma(2s) subtype of GABA(A) receptors was studied. Scatchard analysis of binding data revealed the existence of a single type of binding site for [H-3]TBOB with a K-d of 47.06 +/- 4.06 nM and a B-max value of 6.72 +/- 0.52 pmol/mg protein. GABA, thiopental, TBOB, picrotoxin and the neurosteroid dehydroepiandrosterone sulfate displaced concentration-dependently the binding of [H-3]TBOB to this recombinant receptor. Dehydroepiandrosterone sulfate reversed the 5 mu M GABA-induced inhibition of specific [H-3]TBOB binding. It is concluded that membranes isolated from HEK 293 cells stably transfected with alpha(1)beta(2)gamma(2s) subunits exhibit specific high-affinity [H-3]TBOB binding. The potency of drugs to inhibit [H-3]TBOB binding mainly corresponded to that observed for the inhibition of the binding of cage convulsants to the native receptors or to transiently transfected HEK 293 cells.

(3H)TBOB (t-(3H)butylbicycloorthobenzoate) binding; GABA-A receptor; recombinant; GABA (gamma-aminobutyric acid); thiopental; picrotoxin; dehydroepiandrosterone sulfate

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