3-Nitropropionic acid produces striatum selective lesions accompanied by iNOS expression

Systemically administered 3-nitropropionic acid (3-NPA) that inhibits the mitochondrial oxidative phosphorylation induces selective lesions in the striatum. To investigate the nature of these selective lesions, we administered 3-NPA (20 mg/kg, s.c. daily for 2 or 3 days) to Wistar rats and investigated the behavioral disturbance, striatal lesions and their variations after modulating the activity of nitric oxide synthase (NOS). On the second or third day of 3-NPA administration, half the animals manifested behavioral disturbances (paddling, rolling, tremor, abnormal gait, and recumbence). A strong extravasation of immunoglobulin G (IgG) and a decrease in immunoreaction for glial fibrillary acidic protein (GFAP) were detected, and iNOS-like (iNOS-L) immunoreactive small cells appeared in the lateral and central striatum especially around the vessels. A week later, lesions lacking GFAP-immunoreaction were detected in the striatum in survived animals. Pretreatment with N-nitro- l-arginine methyl ester ( l-NAME) along with each injection of 3-NPA did not improve the behavioral disturbances nor the survival rate, but attenuated the extravasation of IgG and iNOS-L immunoreaction. Pretreatment with aminoguanidine or FK506 improved the behavioral symptoms and survival rate. Extravasation of IgG and expression of iNOS-L immunoreactivity were attenuated, and the striatal lesion was reduced. Data indicate the involvement of NO in the high vulnerability of the striatum, and that iNOS, one of inflammatory markers, is induced following exposure to 3-NPA.