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Properties of benzodiazepine binding sites in peripheral blood lymphocytes

1989; Wiley; Volume: 3; Issue: 6 Linguagem: Inglês

10.1002/jcla.1860030603

1098-2825

L. Garau, Mauro A.M. Carai, W. Boi, Maria Grazia Ennas, Paolo Emilio Manconi, PierFranco Spano, Maurizio Memo, Marina Pizzi, C. Misale,

Synthesis and pharmacology of benzodiazepine derivatives

Abstract Benzodiazepine (BDZ) binding sites were studied by using 3 H‐diazepam and 3 H‐Ro 5‐4864 in intact lymphocytes from peripheral blood (PBL), in comparison to kidney and cerebellum. Experiments with 3 H‐diazepam performed at equilibrium and measuring kinetics revealed that BDZ binding sites are indeed present in rat PBL. The binding is saturable (Bmax 557 fmoles/10 6 cells), with high affinity (KD = 9.3 nM) and reversible. Specific binding sites are also observed by saturation experiments with 3H‐Ro 5‐4864 (Bmax 175 fmoles/10 6 cells, KD 2.2 nM). In addition, analysis of saturation isotherms obtained with 3 H‐diazepam indicates that BDZ binding sites are also present in human PBL. Scatchard plot of binding isotherms revealed an apparent single population of sites in all cases. The pharmacological characterization of BDZ binding sites in PBL, as compared with those of kidney and cerebellum, showed that these sites belong to the so‐called “peripheral type”.