THE EXPRESSION OF ORNITHINE DECARBOXYLASE ANTIZYME MESSENGER-RNA AND PROTEIN IN RAT MOTONEURONS

The distribution of ornithine decarboxylase antizyme messenger ribonuc leic acid (AZ mRNA) and AZ-like immunoreactivity (LI) was studied in t he brainstem and spinal cord motoneurons and in the extraocular and tr iceps surae muscles of rat. In situ hybridization showed AZ mRNA in th e gray matter of the spinal cord at different levels of spinal cord wi th highest AZ mRNA levels in the ventral horn of the spinal cord. No a pparent changes in AZ mRNA contents were seen after unilateral transec tion of the sciatic nerve in lumbar motoneurons. AZ-immunoreactive (IR ) motoneurons were observed in the nucleus of the VI cranial nerve and in the ventral horn of the spinal cord. These motoneurons also showed ornithine decarboxylase (ODC)-LI. Subcellularly, AZ-LI was observed b oth in the nuclei and cytoplasm of labeled motoneurons. Heavily staine d AZ-IR nerve fibers and myoneural junctions were observed among muscl e fibers in different muscles. In addition, the nuclei of muscle fiber s showed AZ-LI.