Induction of microglial nitric oxide synthesis by very low density lipoprotein

The effect of lipoproteins on adult rat CNS microglial nitric oxide (NO) production was studied. Incubation of cultured microglia with very low density lipoprotein (VLDL) for 48 h induced a 13-fold increase in NO production, compared with control. However, the induction of NO was negated when cells were incubated with VLDL and the NO synthase inhibitor N-methyl-L-arginine. High and low density lipoproteins (HDL and LDL) did not significantly induce NO synthesis in microglial cells. These results suggest that the lipoprotein environment in the brain can influence neurotoxic activity of microglia via production of NO.