["Sulthiame is a carbonic anhydrase (CA) inhibitor with an anticonvulsant effect in the treatment of benign and symptomatic focal epilepsy in children. The aim of the study was to elucidate the mode of action of sulthiame with respect to possible changes of intracellular pH (pHi) that might develop along with sulthiame's anticonvulsant properties.", "The effects of sulthiame (a) on pHi of 2',7-bis(2-carboxyethyl)-5(6)-carboxyfluorescein-acetoxymetyl ester (BCECF-AM) loaded CA3 neurones as well as (b) on epileptiform activity (induced by 50 microM 4-aminopyridine) were compared with those of the CA inhibitors acetazolamide and benzolamide.", 'In the majority of neurons, sulthiame (1.0-1.5 mM; n = 8) as well as the membrane permeant acetazolamide (0.5-1.0 mM; n = 6) reversibly decreased pHi by 0.18 +/- 0.05 (SD) and 0.17 +/- 0.10 (SD) pH units, respectively, within 10 min. The poor membrane permeant benzolamide (1.0-2.0 mM) had no influence on pHi (n = 8). Sulthiame (1.0-2.5 mM) and acetazolamide (1.0-2.0 mM) reversibly reduced the frequency of action potentials and epileptiform bursts after 10-15 min (n = 9, n = 7), whereas benzolamide (1.0-2.0 mM) had no effect (n = 6).'] Does carbonic anhydrase inhibitor sulthiame reduce intracellular pH and epileptiform activity of hippocampal CA3 neurons?