Benzodiazepines are weak inhibitors of [3H]nitrobenzylthioinosine binding to adenosine uptake sites in brain.

Saturable, specific, high affinity binding of the potent adenosine uptake inhibitor [3H]nitrobenzylthioinosine ([3H]NBI) to brain membranes has been demonstrated. In an effort to test the hypothesis that benzodiazepine action may be due to the inhibition of adenosine uptake, the inhibition of [3H]NBI binding by diazepam, clonazepam and chlordiazepoxide was tested. The benzodiazepines are very weak inhibitors of [#H]NBI binding, having IC50 values several orders of magnitude above their therapeutic levels.