Innervation of the human adrenal gland

OBJECTIVE: To study the innervation of the human adrenal gland by immunohistochemical techniques using monoclonal antibodies against the 200-kDa phosphorylated neurofilament and S-100 protein, specific markers of the axons and Schwann cells, respectively. METHODS: 24 specimens of normal adrenal gland from patients that had undergone radical nephrectomy for a renal tumor were analyzed. The tissue was embedded in paraffin and prepared for analysis by immunohistochemical techniques with the indirect peroxidase method using primary monoclonal antibodies against the 200-kDA phosphorylated neurofilament and protein S-100. RESULTS: The nerves localized in the adrenal gland form a subcapsular plexus where branches arise that extend to the medulla and come into contact with the enterochromaffin cells and medullary neurons. The adrenal neurons are restricted to the medulla; they are dispersed or form ganglia. The satellite cells of the medullary ganglia and the sustentacular cells were positive for S-100. CONCLUSIONS: Most of the nerve fibers penetrate into the human adrenal gland, extending directly to the medulla apparently without coming into contact with the cells of the adrenal cortex and form similar connections to the synaptics with the chromaffin cells and the medullary neurons. The microganglia of the human adrenal gland are dispersed and comprised of few neurons.