Wen-xin Zhao; Mu Pang & Zhi-zhou Shi

Horner syndrome (HS) is highlighted by a lack of sympathetic signaling due to the lesion in the upper or lower motor neurons. One of the manifestations of HS could be eye displacement due to the denervation of capsulopalpebral fascia, Müller's, and Kakizaki's muscles. In this study, the lack of a sympathetic system on lipolysis was evaluated. The interaction of the ligands to the sympathetic and parasympathetic receptors was performed using Autodock Vina and ClusPro. The molecular signaling pathway involved in the sympathetic and parasympathetic pathways was analyzed by STRING. Magnetic resonance spectroscopy (MRS) was utilized to measure the neurochemistry of locus coeruleus (LC). The results of the MRS suggested an increase in the LC activity. There was an increase in the lactate value of LC, while there was a decrease in the GABA and choline levels in the affected side in the HS patients. The result of STRING, and molecular docking revealed the involvement of the PACAP and beta 3 adrenergic receptor in the lipolysis. Moreover, the involvement of the PACAP in the activation of the alpha 2 adrenergic receptor suggested its regulatory effect in inducing or inhibiting lipolysis. In the HS the sympathetic system is disrupted, while the parasympathetic system remains intact. The parasympathetic system could control lipolysis through PACAP secretion. This phenomenon is suggested to influence the eye displacement observed in some HS patients.

KEY WORDS: Locus coeruleus; PAG; PACAP; Autonomic nervous system.

ZHAO, W-X.; PANG, M. & SHI, Z-Z. Beyond the sympathetic and parasympathetic nerves; the time has come to classify the autonomic system based on adrenergic or cholinergic transmission: What is happening in the nervous system? Int. J. Morphol., 43(6):1833-1842, 2025.