COCAINE INDUCES INTRACELLULAR FREE MG DEFICITS, ISCHEMIA AND STROKE AS OBSERVED BY INVIVO P-31-NMR OF THE BRAIN

P-31-NMR spectroscopic studies were performed in vivo on brains of rats administered cocaine. Cocaine . HCl (1-5 mg/kg) administered systemically to lightly anesthetized rats resulted in significant and progressive deficits in whole brain intracellular free Mg ([Mg2+]i). Intracellular pH (pH(i)) also fell in a progressive manner but only after a significant fall in brain [Mg2+]i was noted. Both [Mg2+]i and pH(i) returned to normal in most rats. Brains of rats that exhibited stroke-like events, however, demonstrated continued intracellular acidosis associated with progressive loss of phosphocreatine and elevation of P(i) up until death. These observations are consistent with the tenet that injection of cocaine can result in severe cerebral vasospasm, ischemia and rupture of cerebral blood vessels as a consequence of depletion of brain [Mg2+]i.