Enalapril increases postischaemic cerebral oxygen and glucose consumption in cats

The purpose of this study was to investigate whether enalapril - an angiotensin converting enzyme inhibitor - has an effect on oxygen consumption and glucose utilization by the brain after ischaemia. The experiments were carried out on anaesthetized cats under artificial respiration and autohemoperfusion of the brain with a constant volume of blood using a resistograph. Tissue levels of oxygen and glucose were determined using a radiometer and their consumption was determined by the arterio-venous differences taking into account the blood flow rate. Brain ischaemia was simulated by 15-minutes arrest of the autohemoperfusion pump and reducing the arterial pressure to 40-30 mm Hg by haemorrhage. In the postischaemic period in the cat brain, control experiments proved that consumption of oxygen and glucose by the brain falls drastically with the development of metabolic acidosis. Intravenous infusion of enalapril (0.25 mg kg^-1) ten minutes into the postischaemic period increased oxygen and glucose consumption by the brain. The result of this study suggests that enalapril improves oxygen and glucose consumption, changes the degree of acidosis of the postischaemic brain and the important role of the renin-angiotensin system in the occurrence of postischaemic cerebrovascular events was implicated.