Pan-neuronal expression of chromogranin A in rat nervous system

Sensitive and specific in situ hybridization detection of CGA mRNA, and immunohistochemistry with an antibody recognizing the CGA(316-329) epitope within CGA and its proteolytic fragments were employed to determine whether or not CGA mRNA or protein expression are restricted to specific neuronal subpopulations within the central and peripheral nervous systems. Virtually all neurons in sympathetic, sensory, and parasympathetic ganglia examined, as well as enteric nervous system and spinal cord, expressed both CGA mRNA and the 316-329 (WE-14) CGA epitope. Chromogranin A expression was also ubiquitous within all telencephalic and diencephalic brain nuclei examined, including frontal cortex, striatum, and hippocampus. In addition, CGA mRNA was expressed in nonneuronal cells that appeared to be glia in dorsal root ganglion, spinal cord, and brain. In contrast to earlier reports, neuronal expression of CGA appears to be unrestricted within the central and peripheral nervous systems. Nonneuronal expression of CGA also occurs in the nervous system, albeit at levels much lower than in neuronal cells.