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Mesa-Lombardo A, García-Magro N, Nuñez A, Martin YB. Locus coeruleus inhibition of vibrissal responses in the trigeminal subnucleus caudalis are reduced in a diabetic mouse model. Front Cell Neurosci 2023; 17:1208121. [PMID: 37475984 PMCID: PMC10354250 DOI: 10.3389/fncel.2023.1208121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 06/09/2023] [Indexed: 07/22/2023] Open
Abstract
Diabetic neuropathy is the loss of sensory function beginning distally in the lower extremities, which is also characterized by pain and substantial morbidity. Furthermore, the locus coeruleus (LC) nucleus has been proposed to play an important role in descending pain control through the activation of α2-noradrenergic (NA) receptors in the spinal dorsal horn. We studied, on control and diabetic mice, the effect of electrical stimulation of the LC nucleus on the tactile responses in the caudalis division of the spinal trigeminal nucleus (Sp5C), which is involved in the relay of orofacial nociceptive information. Diabetes was induced in young adult C57BL/6J mice with one intraperitoneal injection of streptozotocin (50 mg/kg) daily for 5 days. The diabetic animals showed pain in the orofacial area because they had a decrease in the withdrawal threshold to the mechanical stimulation in the vibrissal pad. LC electrical stimulation induced the inhibition of vibrissal responses in the Sp5C neurons when applied at 50 and 100 ms before vibrissal stimulation in the control mice; however, the inhibition was reduced in the diabetic mice. These effects may be due to a reduction in the tyrosine hydroxylase positive (TH+) fibers in the Sp5C, as was observed in diabetic mice. LC-evoked inhibition was decreased by an intraperitoneal injection of the antagonist of the α2-NA receptors, yohimbine, indicating that it was due to the activation of α2-NA receptors. The decrease in the LC-evoked inhibition in the diabetic mice was partially recovered when clonidine, a non-selective α2-agonist, was injected intraperitoneally. These findings suggest that in diabetes, there is a reduction in the NA inputs from the LC in the Sp5C that may favor the development of chronic pain.
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Affiliation(s)
- Alberto Mesa-Lombardo
- Department of Anatomy, Histology and Neurosciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - Nuria García-Magro
- Facultad de Ciencias de la Salud, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Madrid, Spain
| | - Angel Nuñez
- Department of Anatomy, Histology and Neurosciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - Yasmina B. Martin
- Facultad de Medicina, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Madrid, Spain
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Kohno K, Shirasaka R, Yoshihara K, Mikuriya S, Tanaka K, Takanami K, Inoue K, Sakamoto H, Ohkawa Y, Masuda T, Tsuda M. A spinal microglia population involved in remitting and relapsing neuropathic pain. Science 2022; 376:86-90. [PMID: 35357926 DOI: 10.1126/science.abf6805] [Citation(s) in RCA: 91] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neuropathic pain is often caused by injury and diseases that affect the somatosensory system. Although pain development has been well studied, pain recovery mechanisms remain largely unknown. Here, we found that CD11c-expressing spinal microglia appear after the development of behavioral pain hypersensitivity following nerve injury. Nerve-injured mice with spinal CD11c+ microglial depletion failed to recover spontaneously from this hypersensitivity. CD11c+ microglia expressed insulin-like growth factor-1 (IGF1), and interference with IGF1 signaling recapitulated the impairment in pain recovery. In pain-recovered mice, the depletion of CD11c+ microglia or the interruption of IGF1 signaling resulted in a relapse in pain hypersensitivity. Our findings reveal a mechanism for the remission and recurrence of neuropathic pain, providing potential targets for therapeutic strategies.
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Affiliation(s)
- Keita Kohno
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.,Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Ryoji Shirasaka
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kohei Yoshihara
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Satsuki Mikuriya
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kaori Tanaka
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Keiko Takanami
- Ushimado Marine Institute, Graduate School of Natural Science and Technology, Okayama University, Setouchi, Japan.,Mouse Genomics Resources Laboratory, National Institute of Genetics, Shizuoka, Japan
| | - Kazuhide Inoue
- Kyushu University Institute for Advanced Study, Fukuoka, Japan
| | - Hirotaka Sakamoto
- Ushimado Marine Institute, Graduate School of Natural Science and Technology, Okayama University, Setouchi, Japan
| | - Yasuyuki Ohkawa
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Takahiro Masuda
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.,Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Makoto Tsuda
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.,Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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