Abstract: ObjectiveTo observe the changes of artery diameters, cerebral blood flow and glutamate level in the early stage (2 h after the stimulus finished) of acute mechanical middle cerebral artery (MCA) vasospasm in cats. MethodsThe right MCA was persistently mechanically stimulated using a small smooth stainless steel nail in the field across the olfactory tract for 30 min. The diameter of MCA was recorded with metrical ocular of microscope. The changes of the perfusion index of brain tissue were observed through the Laser Doppler flowmetry monitor fixed on the skull. The level of glutamate were investigated through high performance liquid chromatography. ResultsThe diameter of MCA decreased to 68.8% of normal. 2 h later, the diameter of MCA recovered. The perfusion index of the cortex surface decreased to 42.6% of normal and up to 63.8% 2 h later. The level of glutamate raised about 40 times of normal and maintained a high level 2 h after the mechanical stimulus. ConclusionThe persistent mechanical stimulus can cause acute cerebral vasospasm. Reduce of cerebral blood flow and raise of excitatory amino acids were observed in the early stage of acute mechanical vasospasm.

Key words: craniotomy, vasospasm, glutamate, cats