Effects of intracerebral microinjection of hydroxylated-[60]fullerene on brain monoamine concentrations and locomotor behavior in rats.

Fullerenes are condensed ring aromatic compounds with extended pi systems; they have unique cage structures. Current studies suggest that several fullerene derivatives have neuroprotective effects, and it is expected that fullerenes will be useful in drug delivery system and novel medical devices targeting the brain. However, little is known about the effects of fullerenes and its derivative on brain function. We examined the effect of fullerene(OH)24 on the central nervous system in this study. In a V79 colony assay, the IC50 of fullerene(OH)24 was 1.74 microg/ml. In an MTT assay, fullerene(OH)24 reduced proliferation of normal human astrocytes obviously. In an vivo study, 0.25 mg/kg(-1) of fullerene(OH)24 was injected into the lateral ventricle of rat brains. The intracerebral injection of fullerene(OH)24 remarkably decreased body weight and locomotor behavior of rats on day 1, but drastically increased locomotor behavior on day 7. The intracerebral injection of fullerene(OH)24 changed the monoamine concentration greatly on day 1 and slightly on day 30 after the injection. These results suggest that intracerebral injection of fullerene(OH)24 had strong and acute effects on the central nervous system, but that the effects were not permanent. In conclusion, we suggest that fullerene's derivative, fullerene(OH)24 had toxic effects on brain cells and that intracerebral injection of fullerene(OH)24 had acute harmful effects on brain monoamines neurotransmission and locomotor activity.