Altered phosphorylation of rat neuronal cytoskeletal proteins in acrylamide induced neuropathy

The activity of protein kinase has been assayed in neurofilament preparations from spinal cords of rats treated with acrylamide. Animals received 50 mg/kg, i.p., of acrylamide per day for a total of 5 or 10 days; these doses produce mild and marked symptoms of neurological damage, respectively. Incorporation of phosphate into proteins was determined using [gamma-32P]ATP followed by SDS-PAGE. Total phosphorylation of neurofilament preparations was significantly increased only in the animals treated with the 500 mg/kg cumulative dose of acrylamide. Phosphorylation of the 200 and 155 kdalton subunits of the neurofilaments was increased by 20-40% in the acrylamide treated groups. The phosphorylation of the 70 kdalton neurofilament subunit was unchanged in the 250 mg/kg group and was significantly decreased in the 500 mg/kg group. Phosphorylation of other protein bands was not altered. These results suggest a mechanism by which acrylamide might produce axonal neurofilamentous accumulations.