Chromogranin A in neurons of the rat cerebellum and spinal cord: quantification and sites of expression

Chromogranin A (CGA) is an abundant protein of dense-cored
secretory vesicles in endocrine and neuronal cells. The present
study, for the first time, compares CGA of neurons of the central
nervous system with the CGA of adrenal origin. By S1 nucleus
protection assay, we found that the 3' part of the CGA mRNA between
exons 5-8 of the cerebellum and the spinal cord of the rat is
homologous to that of the adrenal. In situ hybridization
histochemistry revealed that CGA mRNA in the cerebellar cortex is
present in cell bodies of Purkinje cells and in neurons of the deep
cerebellar nuclei. The perikarya of these cells also exhibit
CGA-like immunoreactivity. CGA mRNA and CGA-like immunoreactivity
are also present in the motoneurons of the ventral, lateral, and
dorsal horns of the rat spinal cord. The amounts of CGA, as
determined by radioimmunoassay in cerebellum and spinal cord, were
about one tenth of the amounts detected in the adrenal,
adenohypophysis, or the olfactory bulb. The sites of CGA expression
suggest that CGA may be involved in signal transduction in the
motor system.