L-ARGININE AMELIORATES CEREBRAL BLOOD-FLOW AND METABOLISM AND DECREASES INFARCT VOLUME IN RATS WITH CEREBRAL-ISCHEMIA

Effects of L-arginine, 300 mg/kg, i.p., on the regional cerebral blood flow (rCBF), brain metabolism, and infarct volume were examined in sp ontaneously hypertensive rats subjected to occlusion of both left midd le cerebral artery and left common carotid artery. Rats treated with L -arginine had higher rCBF, determined by hydrogen clearance method, in the ischemic core (7 +/- 1 ml/100 g/min, mean +/- S.E.M.) and penumbr al regions (16 +/- 2) than did rats treated with saline (5 +/- 0 and 7 +/- 1, respectively). Simultaneously, L-arginine attenuated metabolic derangement in the ischemic tissue at 60 min, i.e. well maintained ad enosine triphosphate (ATP) in ischemic region (1.29 +/- 0.07 mmol/kg i n L-arginine group vs. 1.05 +/- 0.06 in saline group), and also close to normal levels in ATP (2.61 +/- 0.02 mmol/kg vs. 2.45 +/- 0.05), glu cose (2.29 +/- 0.12 mmol/kg vs. 1.80 +/- 0.17) and lactate (1.63 +/- 0 .10 mmol/kg vs. 2.24 +/- 0.21) in periischemic region. In another expe riment, the effects of L-arginine on rCBF in the subcortical regions a nd on infarct volume were evaluated. L-arginine, compared with saline, increased rCBF by 8 ml/100 g/min in the ischemic side and reduced inf arct volume by 29% at 24 h of ischemia. These findings support that L- arginine may be potentially useful for the treatment of acute cerebral ischemia.