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Xue Y, Yang YT, Liu HY, Chen WF, Chen AQ, Sheng Q, Chen XY, Wang Y, Chen H, Liu HX, Pang YY, Chen L. Orexin-A increases the activity of globus pallidus neurons in both normal and parkinsonian rats. Eur J Neurosci 2016; 44:2247-57. [PMID: 27336845 DOI: 10.1111/ejn.13323] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 05/04/2016] [Accepted: 06/21/2016] [Indexed: 02/06/2023]
Abstract
Orexin is a member of neuropeptides which was first identified in the hypothalamus. The globus pallidus is a key structure in the basal ganglia, which is involved in both normal motor function and movement disorders. Morphological studies have shown the expression of both OX1 and OX2 receptors in the globus pallidus. Employing single unit extracellular recordings and behavioural tests, the direct in vivo electrophysiological and behavioural effects of orexin-A in the globus pallidus were studied. Micro-pressure administration of orexin-A significantly increased the spontaneous firing rate of pallidal neurons. Correlation analysis revealed a negative correlation between orexin-A induced excitation and the basal firing rate. Furthermore, application of the specific OX1 receptor antagonist, SB-334867, decreased the firing rate of pallidal neurons, suggesting that endogenous orexinergic systems modulate the firing activity of pallidal neurons. Orexin-A increased the excitability of pallidal neurons through both OX1 and OX2 receptors. In 6-hydroxydopamine parkinsonian rats, orexin-A-induced increase in firing rate of pallidal neurons was stronger than that in normal rats. Immunostaining revealed positive OX1 receptor expression in the globus pallidus of both normal and parkinsonian rats. Finally, postural test showed that unilateral microinjection of orexin-A led to contralateral deflection in the presence of systemic haloperidol administration. Further elevated body swing test revealed that pallidal orexin-A and SB-334867 induced contralateral-biased swing and ipsilateral-biased swing respectively. Based on the electrophysiological and behavioural findings of orexin-A in the globus pallidus, the present findings may provide a rationale for the pathogenesis and treatment of Parkinson's disease.
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Affiliation(s)
- Yan Xue
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Yu-Ting Yang
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Hong-Yun Liu
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China.,Department of Pathology, Qingdao Municipal Hospital, Qingdao, China
| | - Wen-Fang Chen
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - An-Qi Chen
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Qing Sheng
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Xin-Yi Chen
- Department of Neurology, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Ying Wang
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Hua Chen
- Department of Pathology, Qingdao Municipal Hospital, Qingdao, China
| | - Hong-Xia Liu
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Ya-Yan Pang
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Lei Chen
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
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