Lack of neurochemical evidence for neurotoxic effects of repeated cocaine administration in rats on brain monoamine neurons.

Rats were injected with cocaine (20 mg/kg, s.c. or i.p. twice daily for 8 days) or saline and killed at 1, 8, 15 or 48 days after the last injection. The concentrations of norepinephrine (NE), dopamine (DA), serotonin (5-HT) and their metabolites, assayed by HPLC-EC, in frontal cortex, hippocampus, striatum, hypothalamus, midbrain, pons-medulla and spinal cord were not significantly different from those in the saline-injected controls at any of the time points examined. These data suggest that the repeated cocaine administration in rats does not produce any long-term depletion in brain catecholamine and 5-HT content suggesting no neurotoxic effects of the drug.