RET-LIKE IMMUNOSTAINING OF SPINAL MOTONEURONS IN AMYOTROPHIC-LATERAL-SCLEROSIS

The receptor tyrosine kinase RET is part of a functional receptor for glial cell derived neurotrophic factor (GDNF) and neurturin (NTN) whic h are potent neurotrophic factors for motoneurons. Here, we have studi ed RET-like immunoreactivity of motoneurons in post-mortem spinal cord s of patients with amyotrophic lateral sclerosis (ALS) and in controls . We report that the intensity of RET-like immunostaining of motoneuro ns in ALS is decreased significantly to 81% of control values. Despite this change, the proportion of all large (> 40 mu m diameter) motoneu rons showing RET-like immunoreactivity in ALS remains high (82-85%) an d is not significantly different to controls. The persistence of RET-l ike immunoreactivity in the majority of large motoneurons in ALS could be important in the design of clinical trials of GDNF and NTN. (C) 19 98 Elsevier Science B.V.