Optimization of magnesium therapy after severe diffuse axonal brain injury in rats

A number of studies have demonstrated that magnesium salts given after traumatic brain injury improve subsequent neuro-logic outcome. However, given that these earlier studies have used a number of different salts, dosages, and routes of ad-ministration, follow-up studies of the neuroprotective proper-ties of magnesium are complicated, with comparisons to the earlier literature virtually impossible. The present study has therefore characterized the dose-response characteristics of the most commonly used sulfate and chloride salts of magne-sium in a severe model of diffuse traumatic axonal injury in rats. Both magnesium salts improved neurologic outcome in rats when administered as a bolus at 30 min after injury. The i.v. and i.m. optima of each salt was 250 mmol/kg and 750 mmol/kg, respectively. The identical concentrations required for im