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BioMed Research International
Volume 2017 (2017), Article ID 2034691, 9 pages
https://doi.org/10.1155/2017/2034691
Research Article

α-MSH Influences the Excitability of Feeding-Related Neurons in the Hypothalamus and Dorsal Vagal Complex of Rats

1Department of Clinical Hematology, Medical College, Qingdao University, Qingdao, China
2Department of Special Medicine, Medical College, Qingdao University, Qingdao, China
3Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College, Qingdao University, Qingdao, China

Correspondence should be addressed to Hong-Zai Guan; moc.361@iazgnohnaug and Xi Chen; moc.361@1021yesac

Received 30 July 2017; Revised 7 October 2017; Accepted 22 October 2017; Published 26 November 2017

Academic Editor: Geyang Xu

Copyright © 2017 Hong-Zai Guan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Alpha-melanocyte-stimulating hormone (α-MSH) is processed from proopiomelanocortin (POMC) and acts on the melanocortin receptors, MC3 and MC4. α-MSH plays a key role in energy homeostasis. In the present study, to shed light on the mechanisms by which α-MSH exerts its anorectic effects, extracellular neuronal activity was recorded in the hypothalamus and the dorsal vagal complex (DVC) of anesthetized rats. We examined the impact of α-MSH on glucose-sensing neurons and gastric distension (GD) sensitive neurons. In the lateral hypothalamus (LHA), α-MSH inhibited 75.0% of the glucose-inhibited (GI) neurons. In the ventromedial nucleus (VMN), most glucose-sensitive neurons were glucose-excited (GE) neurons, which were mainly activated by α-MSH. In the paraventricular nucleus (PVN), α-MSH suppressed the majority of GI neurons and excited most GE neurons. In the DVC, among the 20 GI neurons examined for a response to α-MSH, 1 was activated, 16 were depressed, and 3 failed to respond. Nineteen of 24 GE neurons were activated by α-MSH administration. Additionally, among the 42 DVC neurons examined for responses to GD, 23 were excited (GD-EXC) and 19 were inhibited (GD-INH). Fifteen of 20 GD-EXC neurons were excited, whereas 11 out of 14 GD-INH neurons were suppressed by α-MSH. All these responses were abolished by pretreatment with the MC3/4R antagonist, SHU9119. In conclusion, the activity of glucose-sensitive neurons and GD-sensitive neurons in the hypothalamus and DVC can be modulated by α-MSH.