부산대학교 도서관

Cerebellar Purkinje cells in the rat express low-affinity nerve growth factor receptor (p75 NGFR) antigen during development, but rarely in normal adult animals. In striking contrast, re-expression of p75 NGFR-immunoreactive protein was reported by light microscopy immunocytochemistry in adult rat Purkinje cells as early as 1 day after traumatic axotomy. Characteristically, varicose axons through the infraganglionic zone were also stained. To date, however, there is no information on the subcellular location of the antigenic re-expression. To address this, a pre-embedding immunocytochemical ultrastructural study using affinity-purified monoclonal 192-IgG was carried out after an experimentally induced traumatic lesion of the rat cerebellum. At the electron microscopic level, immunostaining was intense in Purkinje cells. In these cells, the immunoreactivity was always associated with the internal face of the membranes of the rough endoplasmic reticulum, Golgi apparatus and nuclear envelope. Patches of immunoreactivity were also associated with the outer surface of the plasma membrane of the cell body, dendritic processes and axons. It is noteworthy that receptor immunoreactivity was detected in recurrent collaterals of Purkinje cell axons forming symmetric synaptic contacts with the cell body and dendrites of immunonegative local circuit neurons. Results of this study show that injury-induced re-expression of p75 NGFR antigen is restricted to Purkinje cells. Also, the relative importance of the contribution of the local circuit neurons to the production of neurotrophic substances after trauma is suggested. Key words Axotomy * Cerebellum * Immunocytochemistry * Lesion * Neuronal plasticity * Nerve growth factor * Purkinje cell
Introduction Survival and differentiation of neurons depend upon two epigenetic signals: trophic support and neural activity. Nerve growth factor (NGF) (Levi-Montalcini 1987) is the prototype growth factor member of a [...]