Carabersat is a potent anticonvulsant agent. In Vitro: [³H]Carabersat ([³H]SB 204269) binds to rat forebrain membranes with moderate affinity (K_d 40 nM) and pK_i values of 7.3^[1]. Carabersat is able to bind to mouse forebrain membranes, and the binding is saturable and stereospecific, with a K_d of 53 nM. The labelled [³H]Carabersat produces a K_d of 32 nM^[2]. Carabersat (SB-204269, 1-100 μM) has no effect on Na⁺ current in cultured hippocampal neurones. Carabersat also shows no effect on action potential discharges evoked by elevating external K^+[3]. Carabersat (SB-204269) is structurally-related to the benzopyran ATP-sensitive potassium channel (KATP) opener, cromakalim, but has opposite stereochemistry, and the mechanism of action of Carabersat is not thought to involve KATP^[4]. In Vivo: Carabersat (5b) significantly elevates anticonvulsant activity in mice^[1].