BRAIN INTRACELLULAR FREE MAGNESIUM DECLINES AFTER IMPACT-ACCELERATIONINDUCED BRAIN INJURY IN RATS

Significant declines in brain intracellular free magnesium concentrati on (Mgf) have been reported following focal traumatic brain injury but not following diffuse axonal brain injury. Since diffuse axonal brain injury is a common feature of clinical trauma, we have used P-31 magn etic resonance spectroscopy to determine whether Mgf decline is also a feature of a nonfocal traumatic brain injury model that primarily ind uces widespread axonal injury. Impact acceleration-induced injury resu lted in a highly significant decline in Mgf with an associated decline in cytosolic phosphorylation ratio. There were no significant changes in either ATP concentration or brain pH. We propose that decline in b rain Mgf may be a common feature of both focal and diffuse forms of tr aumatic brain injury and therefore a possible target for therapeutic i ntervention.