[Biochemical anatomy of the spinal peptidergic system. Study of normal and pathologic material; plasticity of neuropeptides in adult dorsal root ganglia].

The purpose of this paper is to illustrate the advantages of immunocytochemical studies of spinal neuropeptides in human pathology and in animal experiments. The distribution of neuropeptides in the gray matter of the human spinal cord is summarized. Data obtained on selected pathological cases are able to determine the origin of certain peptidergic afferents to the spinal cord and suggest that the early disappearance of substance P-positive fibers in the motoneuronal columns plays a role in the pathogenesis of amyotrophic lateral sclerosis. In rats, peptide immunocytochemistry is useful for assessing the plasticity of spinal neurons in a model of chronic pain, in chemically induced degeneration of the gray matter and in a model of spinal cord trauma. Finally, a newly developed culture system of adult rat and human dorsal root ganglia demonstrates that the phenotypic expression of neuropeptides can be modulated experimentally, which offers new perspectives for studying the neurobiological role of these mediators and for the tentative repair of spinal lesions by autografts.