Inhibition of constriction of cerebral arterioles in vivo by naftidrofuryl. Action against serotonin and dinoprost

The effect of 2-(diethylamino)ethyl-tetrahydro-α-(1-naphthyl-methyl)-2- furanpropionate (naftidrofuryl, Praxilene®) on an in vivo preparation of mouse cerebral blood vessels was investigated. Naftidrofuryl significantly reduced the arteriolar constriction produced by topical application of serotonin or dinoprost (prostaglandin F(2α)). Local application of 10^-5 mol/l naftidrofuryl reduced both the constrictions to serotonin or dinoprost, when applied simultaneously with either constrictor. However, 10^-7 mol/l naftidrofuryl only inhibited serotonin. Moreover, 30 min after intraperitoneal injection, 160 mg/kg naftidrofuryl inhibited constrictions by either serotonin or dinoprost but 40 mg/kg only inhibited serotonin. 10 mg/kg also inhibited serotonin. The results are compatible with reports of a relatively selective action of naftidrofuryl on the serotonin S₂ receptor. Moreover, while naftidrofuryl has long been suggested as a drug which could enhance cerebral blood flow or improve cerebral ischemia, the present observations suggest an antispasmodic effect on cerebral vessels in vivo.