[3H] diazepam binding to human granulocytes

[3H]-diazepam binds to sites on human granulocyte membranes, with little or no binding to platelets or lymphocytes. These [3H]-diazepam binding sites are of the peripheral type, being strongly inhibited by R05-4864 (Ki = 6.23nM) but only weakly by clonazepam (Ki = 14 microM). Binding of [3H] diazepam at 0 degree is saturable, specific and stereoselective. Scatchard analysis indicates a single class of sites with Bmax of 109 +/- 17f moles per mg of protein and KD of 3.07 +/- 0.53nM. Hill plots of saturation experiments gave straight lines with a mean Hill coefficient of 1.03 +/- 0.014. Binding is time dependent and reversible and it varies linearly with granulocyte protein concentration over the range 0.025-0.300 mg of protein.