Pretreatment with Dixyrazine (10 mg/kg) completely prevents brain edema and significantly reduces the increase of albumin in cerebrospinal fluid (CSF)[2]. In conscious rats subjected to acute hypertension provoked by i.v. adrenaline or bicuculline, the phenothiazine Dixyrazine (5 mg/kg i.v.) has minimal, transient hypotensive effects but significantly reduces the leakage of 126I labeled serum albumin. The diameters of pial arteries and veins are continuously measured with a multichannel videoangiometer through a closed cranial window in anesthetized rats before and after i.v. injection of Dixyrazine (5 mg/kg). Dixyrazine, at a dose of 5 mg/kg, induces a slight transitory decrease in blood pressure (10-20 mm Hg). The maximum mean arterial pressure (MAP) is slightly but not significantly lower in Dixyrazine-treated rats[1].