Autoradiography with [H-3]PK11195 of spinal tract degeneration in amyotrophic lateral sclerosis

The diagnostic hallmarks of amyotrophic lateral sclerosis (ALS) are degener ation of upper and lower motor neurons and of corticospinal tracts. Here, w e demonstrate the suitability of the gliosis marker [H-3]PK11195 for quanti tative evaluation of tract degeneration in ALS in vitro. Binding of [H-3]PK 11195 was increased in lateral and ventral white matter of ALS spinal cords but not in the anterior horn, in spite of a dramatic loss in muscarinic bi nding sites and a high level of oxidatively modified protein. Labeling of a ctivated microglia with [C-11]PK11195 may also allow tract degeneration in ALS to be visualized in vivo.