Pentylenetetrazol may discriminate between different types of benzodiazepine receptors

The effect of various concentrations of pentylenetetrazol (PTZ) on [3H]flunitrazepam binding to benzodiazepine receptors was investigated by Hofstee and Hill plot analyses. These analyses indicate the presence of two PTZ binding sites in forebrain, whereas a single PTZ binding site is present in cerebellum. The relative proportions of the two PTZ binding sites in forebrain are close to those of benzodiazepine Type II and Type I receptors, respectively. These results suggest that PTZ may actually discriminate between different types of benzodiazepine receptors.