Attenuation of hyperalgesia responses via the modulation of 5-hydroxytryptamine signalings in the rostral ventromedial medulla and spinal cord in a 6-hydroxydopamine-induced rat model of Parkinson's disease
| Autor: | Kai-Lin Xia, Cheng-Jie Mao, Li-Fang Hu, Guang-Yin Xu, Chen-Tao Wang, Jun-Yi Liu, Caiyi Zhang, Dong-Jun Lv, Xiao-Qi Zhang, Ya-Ping Yang, Fen Wang, Chun-Feng Liu |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Male Indoles Receptors Opioid mu Rats Sprague-Dawley 0302 clinical medicine Serotonin Agents Medicine pain gamma-Aminobutyric Acid Medulla Oblongata Parkinson Disease Nociception medicine.anatomical_structure Hyperalgesia Molecular Medicine medicine.symptom rostral ventromedial medulla Selective Serotonin Reuptake Inhibitors Signal Transduction Research Article medicine.medical_specialty Serotonin Tyrosine 3-Monooxygenase 5 7-Dihydroxytryptamine Substantia nigra 5-hydroxytryptamine 03 medical and health sciences Cellular and Molecular Neuroscience Internal medicine Nociception assay Animals Oxidopamine Medulla business.industry Pars compacta spinal cord Spinal cord Rats Disease Models Animal 030104 developmental biology Anesthesiology and Pain Medicine Endocrinology nervous system Sympatholytics Parkinson’s disease Rostral ventromedial medulla business Neuroscience 030217 neurology & neurosurgery |
| Zdroj: | Molecular Pain |
| ISSN: | 1744-8069 |
| Popis: | Background Although pain is one of the most distressing non-motor symptoms among patients with Parkinson's disease, the underlying mechanisms of pain in Parkinson's disease remain elusive. The aim of the present study was to investigate the role of serotonin (5-hydroxytryptamine) in the rostral ventromedial medulla (RVM) and spinal cord in pain sensory abnormalities in a 6-hydroxydopamine-treated rat model of Parkinson's disease. Methods The rotarod test was used to evaluate motor function. The radiant heat test and von Frey test were conducted to evaluate thermal and mechanical pain thresholds, respectively. Immunofluorescence was used to examine 5-hydroxytryptamine neurons and fibers in the rostral ventromedial medulla and spinal cord. High-performance liquid chromatography was used to determine 5-hydroxytryptamine and 5-hydroxyindoleacetic acid levels. Results The duration of running time on the rotarod test was significantly reduced in 6-hydroxydopamine-treated rats. Nociceptive thresholds of both mechanical and heat pain were reduced compared to sham-treated rats. In addition to the degeneration of cell bodies and fibers in the substantia nigra pars compacta, the number of rostral ventromedial medulla 5-hydroxytryptamine neurons and 5-hydroxytryptamine fibers in the spinal dorsal horn was dramatically decreased. 5-Hydroxytryptamine concentrations in both the rostral ventromedial medulla and spinal cord were reduced. Furthermore, the administration of citalopram significantly attenuated pain hypersensitivity. Interestingly, Intra-rostral ventromedial medulla (intra-RVM) microinjection of 5,7-dihydroxytryptamine partially reversed pain hypersensitivity of 6-hydroxydopamine-treated rats. Conclusions These results suggest that the decreased 5-hydroxytryptamine contents in the rostral ventromedial medulla and spinal dorsal horn may be involved in hyperalgesia in the 6-hydroxydopamine-induced rat model of Parkinson's disease. |
| Databáze: | OpenAIRE |
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