A purinergic component in the anticonvulsant action of carbamazepine?

The tricyclic anticonvulsant carbamazepine inhibited the binding of [3H]phenylisopropyladenosine (PIA) to rat brain membranes with a K1 value of 44 microM, which is in the range of therapeutic levels of this drug in brain and serum. Other anticonvulsants and tricyclic antidepressants had little effect on PIA binding. Carbamazepine weakly inhibited adenosine uptake into rat brain slices at 400 microM. An effect on adenosine receptors may be an important component of the anticonvulsant action of carbamazepine.