Fig. 2. Competition by benzodiazepines for binding sites labeled by [³H]NBMPR in membranes prepared from guinea pig ventricle and porcine striatum. The competition curves depict results of a single representative experiment from a series of four to eight experiments. The Kⁱand pKⁱvalues for benzodiazepines to compete with [³H]NBMPR are given in table 1.