Effects of Denervation and Axotomy on Nervous System‐Specific Protein, Ornithine Decarboxylase, and Other Enzyme Activities in the Superior Cervical Sympathetic Ganglion of the Rat

The time courses of changes of three enolase isozymes (αα, αγ, and γγ), S‐100 protein, 2′,3′‐cyclic nucleotide 3′‐phosphodiesterase (CNPase), ornithine decarboxylase (ODC), β‐galactosidase, and glucose‐6‐phosphate dehydrogenase (G6PDH) were examined from 1 to 14 days after cutting of the preganglionic nerve (denervation) or the postganglionic nerve (axotomy) of the superior cervical sympathetic ganglion (SCG) of the rat. The wet weight and protein content in the axotomized SCG increased continuously, to nearly twice those of the denervated SCG for 1‐2 weeks after the operations. Among enolase isozymes in the SCG, neuron‐specific γγ‐enolase decreased rapidly after denervation and stayed at a low level for 2 weeks, whereas the isozyme remained almost unchanged after axotomy. On the contrary, ganglionic αα‐enolase and the αγ‐hybrid form increased remarkably to reach a maximum at the second day after axotomy, and remained above control for 1 to 2 weeks; these two enolase isozymes showed little change after denervation. Denervation caused a much larger increase than did axotomy in the ganglionic S‐100 protein, an astrocyte‐specific protein, during the first week after the operation, while the protein content decreased after 2 weeks of either denervation or axotomy. CNPase, a myelin‐associated enzyme, rose suddenly 2 days after axotomy, and remained at a rather high level compared with the denervated ganglion, which showed little variation. Ornithine decarboxylase, a rate‐limiting enzyme catalyzing polyamine biosynthesis, which participates in the regulation of growth and differentiation of the cells, increased significantly within 2–4 days after axotomy and then decreased to a subcontrol level after the next week; the enzyme activity changed only little after denervation. Axotomy caused a gradual decrease of a neuronal marker enzyme, β‐galactosidase activity, but produced an increase of G6PDH, an enzyme essential in lipid biosynthesis for myelin formation.