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Yin JB, Lu YC, Li F, Zhang T, Ding T, Hu HQ, Chen YB, Guo HW, Kou ZZ, Zhang MM, Yuan J, Chen T, Li H, Cao BZ, Dong YL, Li YQ. Morphological investigations of endomorphin-2 and spinoparabrachial projection neurons in the spinal dorsal horn of the rat. Front Neuroanat 2022; 16:1072704. [PMID: 36506871 PMCID: PMC9726772 DOI: 10.3389/fnana.2022.1072704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 11/07/2022] [Indexed: 11/24/2022] Open
Abstract
It has been proved that endomorphin-2 (EM2) produced obvious analgesic effects in the spinal dorsal horn (SDH), which existed in our human bodies with remarkable affinity and selectivity for the μ-opioid receptor (MOR). Our previous study has demonstrated that EM2 made synapses with the spinoparabrachial projection neurons (PNs) in the SDH and inhibited their activities by reducing presynaptic glutamate release. However, the morphological features of EM2 and the spinoparabrachial PNs in the SDH have not been completely investigated. Here, we examined the morphological features of EM2 and the spinoparabrachial PNs by using triple fluorescence and electron microscopic immunohistochemistry. EM2-immunoreactive (-ir) afferents directly contacted with the spinoparabrachial PNs in lamina I of the SDH. Immunoelectron microscopy (IEM) were used to confirm that these contacts were synaptic connections. It was also observed that EM2-ir axon terminals contacting with spinoparabrachial PNs in lamina I contained MOR, substance P (SP) and vesicular glutamate transporter 2 (VGLUT2). In lamina II, MOR-ir neurons were observed to receive direct contacts from EM2-ir varicosities. The synaptic connections among EM2, MOR, SP, VGLUT2, and the spinoparabrachial PNs were also confirmed by IEM. In sum, our results supply morphological evidences for the analgesic effects of EM2 on the spinoparabrachial PNs in the SDH.
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Affiliation(s)
- Jun-Bin Yin
- Department of Human Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, China,Department of Neurology, The 960th Hospital of Joint Logistics Support, PLA, Jinan, China,State Key Laboratory of Military Medical Psychology, The Fourth Military Medical University, Xi’an, China
| | - Ya-Cheng Lu
- Department of Human Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, China
| | - Fei Li
- Department of Human Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, China
| | - Ting Zhang
- Department of Human Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, China
| | - Tan Ding
- Institute of Orthopedics, Xijing Hospital, The Fourth Military Medical University, Xi’an, China
| | - Huai-Qiang Hu
- Department of Neurology, The 960th Hospital of Joint Logistics Support, PLA, Jinan, China,State Key Laboratory of Military Medical Psychology, The Fourth Military Medical University, Xi’an, China
| | - Ying-Biao Chen
- Department of Human Anatomy, Fujian Health College, Fuzhou, China
| | - Hong-Wei Guo
- Department of Neurology, The 960th Hospital of Joint Logistics Support, PLA, Jinan, China
| | - Zhen-Zhen Kou
- Department of Human Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, China
| | - Ming-Ming Zhang
- Department of Human Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, China
| | - Jun Yuan
- Department of Neurology, The 960th Hospital of Joint Logistics Support, PLA, Jinan, China
| | - Tao Chen
- Department of Human Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, China
| | - Hui Li
- Department of Human Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, China
| | - Bing-Zhen Cao
- Department of Neurology, The 960th Hospital of Joint Logistics Support, PLA, Jinan, China
| | - Yu-Lin Dong
- Department of Human Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, China,Yu-Lin Dong,
| | - Yun-Qing Li
- Department of Human Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, China,*Correspondence: Yun-Qing Li,
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Cellular Mechanisms for Antinociception Produced by Oxytocin and Orexins in the Rat Spinal Lamina II-Comparison with Those of Other Endogenous Pain Modulators. Pharmaceuticals (Basel) 2019; 12:ph12030136. [PMID: 31527474 PMCID: PMC6789548 DOI: 10.3390/ph12030136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 08/31/2019] [Accepted: 09/12/2019] [Indexed: 01/23/2023] Open
Abstract
Much evidence indicates that hypothalamus-derived neuropeptides, oxytocin, orexins A and B, inhibit nociceptive transmission in the rat spinal dorsal horn. In order to unveil cellular mechanisms for this antinociception, the effects of the neuropeptides on synaptic transmission were examined in spinal lamina II neurons that play a crucial role in antinociception produced by various analgesics by using the whole-cell patch-clamp technique and adult rat spinal cord slices. Oxytocin had no effect on glutamatergic excitatory transmission while producing a membrane depolarization, γ-aminobutyric acid (GABA)-ergic and glycinergic spontaneous inhibitory transmission enhancement. On the other hand, orexins A and B produced a membrane depolarization and/or a presynaptic spontaneous excitatory transmission enhancement. Like oxytocin, orexin A enhanced both GABAergic and glycinergic transmission, whereas orexin B facilitated glycinergic but not GABAergic transmission. These inhibitory transmission enhancements were due to action potential production. Oxytocin, orexins A and B activities were mediated by oxytocin, orexin-1 and orexin-2 receptors, respectively. This review article will mention cellular mechanisms for antinociception produced by oxytocin, orexins A and B, and discuss similarity and difference in antinociceptive mechanisms among the hypothalamic neuropeptides and other endogenous pain modulators (opioids, nociceptin, adenosine, adenosine 5’-triphosphate (ATP), noradrenaline, serotonin, dopamine, somatostatin, cannabinoids, galanin, substance P, bradykinin, neuropeptide Y and acetylcholine) exhibiting a change in membrane potential, excitatory or inhibitory transmission in the spinal lamina II neurons.
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Wang GD, Wang XY, Liu S, Xia Y, Zou F, Qu M, Needleman BJ, Mikami DJ, Wood JD. β-Nicotinamide adenine dinucleotide acts at prejunctional adenosine A1 receptors to suppress inhibitory musculomotor neurotransmission in guinea pig colon and human jejunum. Am J Physiol Gastrointest Liver Physiol 2015; 308:G955-63. [PMID: 25813057 PMCID: PMC4451321 DOI: 10.1152/ajpgi.00430.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/18/2015] [Indexed: 01/31/2023]
Abstract
Intracellular microelectrodes were used to record neurogenic inhibitory junction potentials in the intestinal circular muscle coat. Electrical field stimulation was used to stimulate intramural neurons and evoke contraction of the smooth musculature. Exposure to β-nicotinamide adenine dinucleotide (β-NAD) did not alter smooth muscle membrane potential in guinea pig colon or human jejunum. ATP, ADP, β-NAD, and adenosine, as well as the purinergic P2Y1 receptor antagonists MRS 2179 and MRS 2500 and the adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine, each suppressed inhibitory junction potentials in guinea pig and human preparations. β-NAD suppressed contractile force of twitch-like contractions evoked by electrical field stimulation in guinea pig and human preparations. P2Y1 receptor antagonists did not reverse this action. Stimulation of adenosine A1 receptors with 2-chloro-N6-cyclopentyladenosine suppressed the force of twitch contractions evoked by electrical field stimulation in like manner to the action of β-NAD. Blockade of adenosine A1 receptors with 8-cyclopentyl-1,3-dipropylxanthine suppressed the inhibitory action of β-NAD on the force of electrically evoked contractions. The results do not support an inhibitory neurotransmitter role for β-NAD at intestinal neuromuscular junctions. The data suggest that β-NAD is a ligand for the adenosine A1 receptor subtype expressed by neurons in the enteric nervous system. The influence of β-NAD on intestinal motility emerges from adenosine A1 receptor-mediated suppression of neurotransmitter release at inhibitory neuromuscular junctions.
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Affiliation(s)
- Guo-Du Wang
- 1Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio;
| | - Xi-Yu Wang
- 1Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio;
| | - Sumei Liu
- 1Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio;
| | - Yun Xia
- 1Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio; ,2Department of Anesthesiology, College of Medicine, The Ohio State University, Columbus, Ohio; and
| | - Fei Zou
- 1Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio;
| | - Meihua Qu
- 1Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio;
| | - Bradley J. Needleman
- 3Department of Surgery, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Dean J. Mikami
- 3Department of Surgery, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Jackie D. Wood
- 1Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio;
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