Microcirculation in the brain during controlled arterial hypotension. Experimental study of the effect of nipruton

The effect of nipruton (sodium nitroprusside)-induced controlled arterial hypotension on the intracerebral microcirculatory channel was studied on 4 rabbits with transplanted induced tumors (anaplastic astrocytomas) and 7 intact rabbits under general anesthesia. It was found that nipruton injected in doses necessary for marked reduction of arterial pressure (35-45 mm Hg) for a sufficient duration (30-55 minutes) causes no circulatory disorders in the brain. In animals with tachyphylaxis to nitropruton, in which the amount of the injected agent must be increased to 9-10 mg/kg, controlled arterial hypotension even of lesser depth (60-65 mm Hg) and lesser duration (20-25 minutes) can lead to partial obstruction of the intracerebral microcirculatory channel. i. e. to the no-reflow phenomenon.