Two binding sites for [3H]glibenclamide in the rat brain.
The binding of [3H]glibenclamide, a potent sulfonylurea which blocks ATP-sensitive potassium channels, was studied in the rat brain. A Scatchard plot of saturation isotherms suggests that [3H]glibenclamide binds in various brain regions to a high- and a low-affinity binding site (Kd values of 0.21 nM and 111 nM and Bmax values of 41 and 1060 fmol/mg protein, respectively). Competitive binding assays with various unlabelled sulfonylureas showed biphasic displacements of [3H]glibenclamide with pseudo-Hill coefficients significantly different from unity. These data indicate the existence of a heterogeneity of binding sites to [3H]glibenclamide in the rat brain; this may correlate with the variability of effects of sulfonylureas observed from physiological experiments.
Zini
S
S
Laboratoire de neurobiologie et neurophysiologie du développement, INSERM U.29, Paris, France.
Tremblay
E
E
Roisin
M P
MP
Ben-Ari
Y
Y
D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D005905:Glyburide / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009994:Osmolar Concentration; D051381:Rats; D011919:Rats, Inbred Strains; D014316:Tritium
D014316:Tritium; D005905:Glyburide