Pharmacological action of FPL 55712 on canine cerebral arterial segments.

The pharmacological action of a leukotriene antagonist FPL 55712 was studied on canine cerebral arterial segments. FPL 55712 at concentrations of 10(-6)M and 10)-5)M showed dose-dependent inhibition of the constrictor responses of the artery to prostaglandin F2 alpha. The constrictor responses of the artery to either serotonin or haemoglobin were suppressed by 10(-5)M FPL 55712, while 10(-6)M FPL 55712 failed to alter the responses. The KCL-induced constriction was not affected by treatment with either 10(-6)M or 10(-5)M FPL 55712. The present results suggest that FPL 55712 has vasodilator properties other than those related to the inhibition of leukotrienes.