Acute methamphetamine intoxication: brain hyperthermia, blood-brain barrier, brain edema, and morphological cell abnormalities.

Methamphetamine (METH) is a powerful and often abused stimulant with potent addictive and neurotoxic properties. While it is generally assumed that multiple chemical substances released in the brain following METH-induced metabolic activation (or oxidative stress) are primary factors underlying damage of neural cells, in this work we present data suggesting a role of brain hyperthermia and associated leakage of the blood-brain barrier (BBB) in acute METH-induced toxicity. First, we show that METH induces a dose-dependent brain and body hyperthermia, which is strongly potentiated by associated physiological activation and in warm environments that prevent proper heat dissipation to the external environment. Second, we demonstrate that acute METH intoxication induces robust, widespread but structure-specific leakage of the BBB, acute glial activation, and increased water content (edema), which are related to drug-induced brain hyperthermia. Third, we document widespread morphological abnormalities of brain cells, including neurons, glia, epithelial, and endothelial cells developing rapidly during acute METH intoxication. These structural abnormalities are tightly related to the extent of brain hyperthermia, leakage of the BBB, and brain edema. While it is unclear whether these rapidly developed morphological abnormalities are reversible, this study demonstrates that METH induces multiple functional and structural perturbations in the brain, determining its acute toxicity and possibly contributing to neurotoxicity.