An alteration of the blood-brain barrier (BBB) permeability contributes to the development of
brain edema after
stroke. In this study, we evaluated the effects of 3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-
indazole dihydrochloride 3.5 hydrate (DY-9760e), a novel
calmodulin antagonist, on
brain edema formation and BBB integrity in rats subjected to transient focal
ischemia.
DY-9760e (1 mg/kg/h) was intravenously infused for 6 h, starting immediately after reperfusion of a 1-h
middle cerebral artery occlusion. Treatment with
DY-9760e significantly suppressed the increase in water content and the extravasation of
Evans blue dye after transient focal
ischemia. Analysis of a magnetic resonance imaging method revealed that
DY-9760e significantly prevented the development of
brain edema in the cortical region of the ipsilateral hemisphere.
Trifluoperazine, a
calmodulin antagonist that is structurally different from
DY-9760e, also attenuated
brain edema elicited by transient focal
ischemia. Furthermore,
DY-9760e and
trifluoperazine reduced
tumor necrosis factor-alpha-induced hyperpermeability of
inulin through a cultured brain microvascular endothelial cell monolayer, suggesting an involvement of
calmodulin in the regulation of brain microvascular barrier function. The present results demonstrate that
DY-9760e ameliorates
brain edema formation and suggest that this effect may be mediated in part by the inhibition of enhanced BBB permeability after ischemic insults. Thus,
DY-9760e is expected to be a therapeutic
drug for treatment of
acute stroke patients.