Interactions of carbamazepine, chlormethiazole and pentobarbitone with adenosine on hippocampal slices.

1. The effects of the anticonvulsants carbamazepine, chlormethiazole and pentobarbitone and their interactions with adenosine have been studied in rat hippocampal slices. 2. Neither chlormethiazole nor pentobarbitone changed the evoked population spike in CA1 stratum pyramidale, while carbamazepine produced a gradual decline of this potential at concentrations of 100 microM or greater. 3. This effect was not prevented by 8-phenyltheophylline. 4. Only carbamazepine (greater than 20 microM) produced any change of adenosine responses: a slowly developing reduction of the inhibitory action. 5. None of the anticonvulsants altered responses to the amino acid excitant N-methyl-aspartate, or kynurenic acid.