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Updated: May 11, 2026

Quantifying Acute Changes in Renal Sympathetic Nerve Activity in Response to Central Nervous System Manipulations in Anesthetized Rats
Published on: September 11, 2018
Involvement of the orexin system in adrenal sympathetic regulation
Takayuki Nemoto1, Fumiyo Toyoshima-Aoyama, Yuto Ueda
1Department of Pharmacology, Graduate School of Medicine, University of Miyazaki, Miyazaki, Japan.
Abstract:
Orexin (hypocretin) is a neuropeptide secreted from hypothalamic neurons that is known to be activated during motivated behaviors and active waking. Presently, our knowledge of orexin is mainly limited to the central nervous system, and the involvement of the orexin system in peripheral tissues has received little attention. In the present study, we analyzed the existence of the orexin system in the adrenal medulla, which is part of the sympathetic nervous system. Orexin and its receptors are expressed in the bovine adrenal medulla. Orexins stimulated intracellular calcium changes and epinephrine release from cultured bovine adrenal medullary cells. Applied orexin decreased expression of prepro-orexin, orexin receptor-1 and orexin receptor-2, suggesting negative feedback regulation in the adrenal gland. Our results indicate involvement of the orexin system in the sympathetic regulation of the adrenal medulla.
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