METHODS: Three groups were designated for this study: control group, subarachnoid hemorrhage-saline infusion group, and subarachnoid hemorrhage-L-arginine infusion group. A subarachnoid hemorrhage was created by intracisternal injection of autologous blood in New Zealand rabbits. At the fourth day of subarachnoid hemorrhage, latency and amplitude of motor evoked potentials were recorded during intracarotid saline and L-arginine infusion, and compared with motor evoked potential parameters of the control group.

RESULTS: Motor evoked potential latencies were increased, and amplitudes were decreased in all animals before saline and L-arginine infusion on the fourth day of subarachnoid hemorrhage. A decrease in latencies as well as an increase in motor evoked potential amplitudes was observed with short-term intracarotid L-arginine infusion.

CONCLUSION: Intracarotid short term L-arginine infusion significantly improves motor evoked potential parameters after experimental subarachnoid hemorrhage. Keywords : Cerebral vasospasm, Subarachnoid hemorrhage, L-arginine, Nitric oxide, Evoked potential, Transcranial magnetic stimulation