Amphetamine administration improves neurochemical outcome of lateral fluid percussion brain injury in the rat

This study examined the effects of the administration of d-amphetamine on the regional accumulation of lactate and free fatty acids (FFAs) after lateral fluid percussion (FP) brain injury in the rat. Rats were subjected to either FP brain injury of moderate severity (1.9 to 2.0 atm) or sham operation. At 5 min after injury, rats were treated with either d-amphetamine (4 mg/kg, i.p.) or saline. At 30 min and 60 min after brain injury, brains were frozen in situ, and cortices and hippocampi were excised at 0°C. In the saline-treated brain injured rats, levels of lactate were increased in the ipsilateral left cortex and hippocampus at 30 min and 60 min after injury. These increases were attenuated by the administration of d-amphetamine at 5 min after lateral FP brain injury. At 30 and 60 min after FP brain injury, increases in the levels of all individual FFAs (palmitic, stearic, oleic and arachidonic acids) and of total FFAs were also observed in the ipsilateral cortex of the saline-treated injured rats. These increases in the ipsilateral cortex and hippocampus were also attenuated by the administration of d-amphetamine. Neither levels of lactate nor levels of FFAs were increased in the contralateral cortex in the saline-treated injured rats at 30 min or 60 min after FP brain injury. The levels of lactate and FFAs in the contralateral cortex were also unaffected by the administration of d-amphetamine. These results suggest that the attenuation of increases in the levels of lactate and FFAs in the ipsilateral cortex and hippocampus may be involved in the amphetamine-induced improvement in behavioral outcome after lateral FP brain injury.