Buspirone enhances benzodiazepine receptor binding in vivo

The effects of buspirone on benzodiazepine receptors labelled in vivo with [3H]Ro 15-1788 were investigated. While buspirone did not affect the binding of benzodiazepine receptors in vitro, significant dose-related increases were observed in the in vivo labelling of benzodiazepine receptors in mice. However, similar results were also obtained with various neuroleptic agents and apomorphine. Potential mechanisms that may account for these results are discussed, but the data suggest caution in the use of [11C]Ro 15-1788 in positron emission tomography scanning in humans, since labelling by Ro 15-1788 may be affected by factors unrelated to direct changes at the benzodiazepine receptor site.