beta-Carboline binding to deoxycholate solubilized benzodiazepine receptors from calf cerebral cortex

Purinergic control of anxiety: direct behavioral evidence in the rat

The purines inosine and hypoxanthine have been implicated in neurobiological effects associated with benzodiazepine-receptor occupancy, and may be endogenous ligands of benzodiazepin receptors. The behavioral effects of purinergic activation upon anxious behaviors have been less well characterized and understood. We present evidence that purinergic stimulation is sufficient to produce an operationally defined conditioned anxiety response, and that the effect is specific to the benzodiazepine receptor. These findings suggest anxiogenic potency for purines, which may be associated with their normal behavioral and motivational mode of action.

Heterogeneity in the physicochemical properties of deoxycholate-solubilized benzodiazepine receptors from calf cerebral cortex

The hydrodynamic behaviour of benzodiazepine receptors solubilized by deoxycholate from calf cerebral cortex reveals two molecular forms. The Stokes radii are 46.5 A and 67.2 A, and the sedimentation coefficients are 10.9 S and 14.6 S. The calculated apparent molecular weights and frictional ratios suggest either two nearly globular proteins of ca. 200K and 400K daltons each, or two ca. 300K daltons proteins which differ significantly in their degree of asymmetry. The benzodiazepine binding site is located on ca. 51K daltons component(s) in both forms.

Production of a high affinity antiserum to benzodiazepines

Antibodies specific for benzodiazepines were raised in rabbits by immunization with a conjugate of a benzodiazepine derivative, Ro 7-1986/1, with bovine serum albumin. The presence of anti-Ro 7-1986/1 antibodies in the sera was demonstrated by a radioimmunoassay using the radioligand [3H]flunitrazepam ([3h]FNZ). The antibodies displayed a high-affinity for [3H]FNZ (KD = 0.073 +/- 0.003 nM) and and cross-reacted with a broad spectrum of benzodiazepine derivatives. Benzodiazepine levels in samples of sera and urine of benzodiazepine-treated humans were determined. Due to the high sensitivity of the assay only minute volumes (microliter quantities) of body fluids are employed and, therefore, no extraction of the drugs is required. Nitrazepam and diazepam levels as low as 20 picograms can be easily observed. Intoxicating levels of benzodiazepines can be detected by a single measurement in less than 10 min. This radioimmunoassay is advantageous for pharmacokinetic studies, toxicological examinations and forensic medicine due to its high sensitivity, wide-range specificity and technical simplicity.