Topical 5-Carboxamidotryptamine (0.01-1000 μM) to the exposed dura mater encephala produced decreases in diastolic blood pressure, variable changes in meningeal blood flow and increases in conductance (i.e. dilatation) in the middle meningeal artery of anesthetized Wistar rats (serotonin depletion and treated with 20 mg/kg corticosterone).