[
3
H]Carabersat ([
3
H]SB 204269) binds to rat forebrain membranes with moderate affinity (K
d
40 nM) and pK
i
values of 7.3. 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 [
3
H]Carabersat produces a K
d
of 32 nM. 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
+
. 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.