Most ganglion cells in the rat adrenal medulla are noradrenergic.

Nerve cells are located in the rat adrenal medulla but their transmitter phenotype has not yet been determined. In-situ hybridization histochemistry was used to investigate ganglion cells with reference to their putative transmitter. High expression of dopamine beta-hydroxylase (DBH), neuropeptide tyrosine (NPY) and nerve growth factor receptor (NGF-R) mRNA was found in many of these neurons, whereas no detectable labelling was seen using a probe complementary to choline acetyltransferase mRNA. Chromaffin cells were also labelled with the DBH, NPY and NGF-R probes. We propose that the DBH/NPY/NGF-R-positive adrenal medullary ganglion cells are sympathetic postganglionic neurons producing noradrenaline. However, other types of ganglion neurons may also be present in the adrenal medulla.