Species dependent effects of dihydroergosine on [3H]TBOB binding to membranes from the human, rat, bovine and mouse brain.

Dihydroergosine enhanced [3H]TBOB binding to the crude synaptosomal membranes prepared from the whole rat brain and human frontal cortex. Higher concentrations of the same drug inhibited [3H]TBOB binding in the preparations obtained from the whole mouse brain and bovine frontal cortex. Bicuculline-induced enhancement and GABA- or diazepam-induced inhibition of [3H]TBOB binding were similar in the four species examined. The results indicate that dihydroergosine modulates species-dependently GABA/benzodiazepine receptors.