Background:

Carabersat is a potent anticonvulsant agent.

[3H]Carabersat ([3H]SB 204269) binds to rat forebrain membranes with moderate affinity (Kd 40 nM) and pKi values of 7.3[1]. Carabersat is able to bind to mouse forebrain membranes, and the binding is saturable and stereospecific, with a Kd of 53 nM. The labelled [3H]Carabersat produces a Kd 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].

Carabersat (5b) significantly elevates anticonvulsant activity in mice[1].

[1]. Wai N. Chan, et al. Synthesis of Novel trans-4-(Substituted-benzamido)-3,4-dihydro-2H-benzo[b]pyran-3-ol Derivatives as Potential Anticonvulsant Agents with a Distinctive Binding Profile. J. Med. Chem., 1996, 39 (23), pp 4537-4539. [2]. Herdon H, et al. The novel anticonvulsant SB 204269 binds to a stereospecific site in the mouse brain. Eur J Pharmacol. 1996 Oct 31;314(3):R7-8. [3]. Caeser M, et al. Lack of effect of the novel anticonvulsant SB-204269 on voltage-dependent currents in neurones cultured from rat hippocampus. Neurosci Lett. 1999 Aug 13;271(1):57-60. [4]. Crespi F, et al. SB-204269 SmithKline Beecham. IDrugs. 1998 Sep;1(5):595-8.