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Hirsch SJ, Budig A, Husam S, Birklein F. Aged females unilaterally hypersensitize, lack descending inhibition, and overexpress alpha1D adrenergic receptors in a murine posttraumatic chronic pain model. Pain 2024; 165:1966-1977. [PMID: 38408277 DOI: 10.1097/j.pain.0000000000003197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 01/11/2024] [Indexed: 02/28/2024]
Abstract
ABSTRACT Vulnerability to chronic pain is found to depend on age and sex. Most patients with chronic pain are elderly women, especially with posttraumatic pain after bone fracture that prevails beyond the usual recovery period and develops into a complex regional pain syndrome (CRPS). There, a distal bone fracture seems to initiate a pathophysiological process with unknown mechanism. To investigate whether sex, age, and alpha adrenergic receptors also contribute to a CRPS-like phenotype in animals, we performed experiments on tibia-fractured mice. Those mice commonly are resilient to the development of a CRPS-like phenotype. However, we found them to be vulnerable to long-lasting pain after distal bone fracture when they were of old age. These mice expressed mechanical and thermal hypersensitivity, as well as weight-bearing and autonomic impairment following bone trauma, which persisted over 3 months. Site-specific and body side-specific glycinergic and α1D-noradrenergic receptor expression in the spinal cord and the contralateral locus coeruleus were misbalanced. Aged female tibia-fractured mice lost descending noradrenergic inhibition and displayed enhanced spinal activity on peripheral pressure stimuli. Together, changes in the noradrenergic, hence, glycinergic system towards excitation in the pain pathway-ascending and descending-might contribute to the development or maintenance of long-lasting pain. Conclusively, changes in the noradrenergic system particularly occur in aged female mice after trauma and might contribute to the development of long-lasting pain. Our data support the hypothesis that some patients with chronic pain would benefit from lowering the adrenergic/sympathetic tone or antagonizing α1(D).
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Affiliation(s)
- Silke J Hirsch
- Department of Neurology, Unimedizin Mainz, Mainz, Germany
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2
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Ji Y, Shi W, Yang J, Ma B, Jin T, Cao B, Liu X, Ma K. Effect of sympathetic sprouting on the excitability of dorsal root ganglion neurons and afferents in a rat model of neuropathic pain. Biochem Biophys Res Commun 2022; 587:49-57. [PMID: 34864395 DOI: 10.1016/j.bbrc.2021.11.096] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 11/06/2021] [Accepted: 11/27/2021] [Indexed: 01/06/2023]
Abstract
Increased sympathetic nerve excitability has been reported to aggravate a variety of chronic pain conditions, and an increase in the number of sympathetic nerve fibers in the dorsal root ganglion (DRG) has been found in neuropathic pain (NP) models. However, the mechanism of the neurotransmitter norepinephrine (NE) released by sympathetic nerve fiber endings on the excitability of DRG neurons is still controversial, and the adrenergic receptor subtypes involved in this biological process are also controversial. In our study, we have two objectives: (1) To determine the effect of the neurotransmitter NE on the excitability of different neurons in DRG; (2) To determine which adrenergic receptors are involved in the excitability of DRG neurons by NE released by sprouting sympathetic fibers. In this experiment, a unique field potential recording method of spinal cord dorsal horn was innovatively adopted, which can be used for electrophysiological study in vivo. The results showed that: Forty days after SNI, patch clamp and field potential recording methods confirmed that NE enhanced the excitability of ipsilateral DRG large neurons, and then our in vivo electrophysiological results showed that the α2 receptor blocker Yohimbine could block the excitatory effect of NE on A-fiber and the inhibitory effect on C-fiber, while the α2A-adrenergic receptor agonist guanfacine (100 μM) had the same biological effect as NE. Finally, we concluded that NE from sympathetic fiber endings is involved in the regulation of pain signaling by acting on α2A-adrenergic receptors in DRG.
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Affiliation(s)
- Yun Ji
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wenjiao Shi
- Department of Anesthesiology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jie Yang
- Department of Physiology, School of Medicine, Jinan University, Guangzhou, 510632, China
| | - Bingjie Ma
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Tian Jin
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Bingbing Cao
- Department of Anesthesiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510120, China
| | - Xianguo Liu
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China.
| | - Ke Ma
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
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3
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Jeong Y, Wagner MA, Ploutz-Snyder RJ, Holden JE. Pain condition and sex differences in the descending noradrenergic system following lateral hypothalamic stimulation. IBRO Rep 2020; 8:11-17. [PMID: 31890982 PMCID: PMC6931064 DOI: 10.1016/j.ibror.2019.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 12/11/2019] [Indexed: 01/28/2023] Open
Abstract
LH stimulation produced pronociceptive and antinociceptive effects from alpha-adrenoceptors in naïve male and female rats. LH stimulation produced pronociceptive and antinociceptive effects from alpha-adrenoceptors in male CCI rats. LH stimulation produced alpha-adrenoceptor-mediated pronociception, but not antinociception in female CCI rats.
The lateral hypothalamus (LH) is known to modulate nociception via the descending noradrenergic system in acute nociception, but less is known about its role in neuropathic pain states. In naïve females, LH stimulation produces opposing effects of α-adrenoceptors, with α2-adrenoceptors mediating antinociception, while pronociceptive α1-adrenoceptors attenuate the effect. Whether this opposing response is seen in neuropathic conditions or in naïve males is unknown. We used a mixed factorial design to compare male and female rats with chronic constriction injury (CCI) to naïve rats, measured by Total Paw Withdrawal (TPW) responses to a thermal stimulus. Rats received one of three doses of carbachol to stimulate the LH followed by intrathecal injection of either an α1- or an α2-adrenoceptor antagonist (WB4101 or yohimbine, resp.) or saline for control. Overall, naïve rats showed a more pronounced opposing alpha-adrenergic response than CCI rats (p < 0.04). Naïve male and female rats demonstrated antinociception following α1-adrenoceptor blockade and hyperalgesia following α2-adrenoceptor blockade. Male CCI rats also showed dose dependent effects from either WB4101 or yohimbine (p < 0.05), while female CCI rats had significant antinociception from WB4101 (p < 0.05), but no effect from yohimbine. These results support the idea that peripheral nerve damage differentially alters the descending noradrenergic modulatory system in male and female rats, and notably, that female CCI rats do not show antinociception from descending noradrenergic input. These findings are suggestive that clinical therapies that recruit the descending noradrenergic system may require a different approach based on patient gender.
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Affiliation(s)
- Younhee Jeong
- College of Nursing Science, Kyung Hee University, 26 Kyunghee-daero, Dongdaemun-gu, Seoul 130-701, Republic of Korea
| | - Monica A Wagner
- The University of Pittsburgh School of Nursing, 3500 Victoria Street, Victoria Bldg, Pittsburgh, PA 15261, United States
| | - Robert J Ploutz-Snyder
- The University of Michigan School of Nursing, 400 N. Ingalls Bldg, Ann Arbor, MI 48109-5482, United States
| | - Janean E Holden
- The University of Michigan School of Nursing, 400 N. Ingalls Bldg, Ann Arbor, MI 48109-5482, United States
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4
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Drummond PD, Dawson LF, Wood FM, Fear MW. Up-regulation of α 1-adrenoceptors in burn and keloid scars. Burns 2017; 44:582-588. [PMID: 29089212 DOI: 10.1016/j.burns.2017.09.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 08/29/2017] [Accepted: 09/17/2017] [Indexed: 12/30/2022]
Abstract
Stimulation of α1-adrenoceptors evokes inflammatory cytokine production, boosts neurogenic inflammation and pain, and influences cellular migration and proliferation. Hence, these receptors may play a role both in normal and abnormal wound healing. To investigate this, the distribution of α1-adrenoceptors in skin biopsies of burn scars (N=17), keloid scars (N=12) and unscarred skin (N=17) was assessed using immunohistochemistry. Staining intensity was greater on vascular smooth muscle in burn scars than in unscarred tissue, consistent with heightened expression of α1-adrenoceptors. In addition, expression of α1-adrenoceptors was greater on dermal nerve fibres, blood vessels and fibroblasts in keloid scars than in either burn scars or unscarred skin. These findings suggest that increased vascular expression of α1-adrenoceptors could alter circulatory dynamics both in burn and keloid scars. In addition, the augmented expression of α1-adrenoceptors in keloid tissue may contribute to processes that produce or maintain keloid scars, and might be a source of the uncomfortable sensations often associated with these scars.
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Affiliation(s)
- Peter D Drummond
- Centre for Research on Chronic Pain and Inflammatory Diseases, Murdoch University, Perth, Western Australia, Australia.
| | - Linda F Dawson
- Centre for Research on Chronic Pain and Inflammatory Diseases, Murdoch University, Perth, Western Australia, Australia
| | - Fiona M Wood
- Burn Injury Research Unit, School of Surgery, University of Western Australia, Australia; The Fiona Wood Foundation, Perth, Western Australia, Australia; The Burns Service of Western Australia, WA Dept of Health, WA, Australia
| | - Mark W Fear
- Burn Injury Research Unit, School of Surgery, University of Western Australia, Australia; The Fiona Wood Foundation, Perth, Western Australia, Australia
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Nie B, Zhang S, Huang Z, Huang J, Chen X, Zheng Y, Bai X, Zeng W, Ouyang H. Synergistic Interaction Between Dexmedetomidine and Ulinastatin Against Vincristine-Induced Neuropathic Pain in Rats. THE JOURNAL OF PAIN 2017; 18:1354-1364. [PMID: 28690001 DOI: 10.1016/j.jpain.2017.06.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/20/2017] [Accepted: 06/26/2017] [Indexed: 12/29/2022]
Abstract
Antimicrotubulin chemotherapeutic agents such as vincristine (VCR), often induce peripheral neuropathic pain. It is usually permanent and seriously harmful to cancer patients' quality of life and can result in the hampering of clinical treatments. Currently, there is no definitive therapy, and many of the drugs approved for the treatment of other neuropathic pain have shown little or no analgesic effect. It is therefore vital to find new and novel therapeutic strategies for patients suffering from chemotherapeutic agent-induced neuropathic pain to improve patients' quality of life. This study shows that intrathecal injections of dexmedetomidine (DEX), or intraperitoneally administered ulinastatin (UTI) significantly reduces Sprague Dawley rats' mechanical allodynia induced by VCR via upregulation of interleukin-10 expression and activating the α2-adrenergic receptor in dorsal root ganglion (DRG). Moreover, when combined there is a synergistic interaction between DEX and UTI, which acts against VCR-induced neuropathic pain. This synergistic interaction between DEX and UTI may be partly attributed to a common analgesic pathway in which the upregulation of interleukin -10 plays an important role via activating α2-adrenergic receptor in rat dorsal root ganglion. The combined use of DEX and UTI does not affect the rat's blood pressure, heart rate, sedation, motor score, spatial learning, or memory function. All of these show that the combined use of DEX and UTI is an effective method in relieving VCR-induced neuropathic pain in rats. PERSPECTIVE This article documents the synergistic interaction between 2 widely used drugs, DEX and UTI, against VCR-induced neuropathic pain. The results provide a potential target and novel drug administrated method for the clinical treatment of chemotherapy-induced peripheral neuropathic pain.
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Affiliation(s)
- Bilin Nie
- Department of Anesthesiology, Guangdong Women and Children Hospital, Guangzhou, China; Department of Anesthesiology, State Key Laboratory of Oncology in Southern China, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Subo Zhang
- Zhongshan School of Medicine, Guangdong Province Key Laboratory of Brain Function and Disease, Sun Yat-Sen University, Guangzhou, China; Department of Rehabilitation Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Zhuxi Huang
- Department of Rehabilitation Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Jingxiu Huang
- Department of Anesthesiology, State Key Laboratory of Oncology in Southern China, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Xiaodi Chen
- Department of Anesthesiology, State Key Laboratory of Oncology in Southern China, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Yaochao Zheng
- Department of Rehabilitation Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Xiaohui Bai
- Department of Anesthesiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Weian Zeng
- Department of Anesthesiology, State Key Laboratory of Oncology in Southern China, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Handong Ouyang
- Department of Anesthesiology, State Key Laboratory of Oncology in Southern China, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
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6
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Wang LJ, Wang Y, Chen MJ, Tian ZP, Lu BH, Mao KT, Zhang L, Zhao L, Shan LY, Li L, Si JQ. Effects of niflumic acid on γ-aminobutyric acid-induced currents in isolated dorsal root ganglion neurons of neuropathic pain rats. Exp Ther Med 2017; 14:1373-1380. [PMID: 28810599 PMCID: PMC5526125 DOI: 10.3892/etm.2017.4666] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 04/10/2017] [Indexed: 12/15/2022] Open
Abstract
Niflumic acid (NFA) is a type of non-steroidal anti-inflammatory drug. Neuropathic pain is caused by a decrease in presynaptic inhibition mediated by γ-aminobutyric acid (GABA). In the present study, a whole-cell patch-clamp technique and intracellular recording were used to assess the effect of NFA on GABA-induced inward current in dorsal root ganglion (DRG) neurons of a chronic constriction injury (CCI) model. It was observed that 1–1,000 µmol/l GABA induced a concentration-dependent inward current in DRG neurons. Compared with pseudo-operated rats, the thermal withdrawal latency (TWL) of CCI rats significantly decreased (P<0.01); however, the TWLs of each NFA group (50 and 300 µmol/l) were significantly longer than that of the CCI group (P<0.01). In the CCI group, the response evoked by GABA (10−6-10−3 mol/l) was reduced in a concentration dependent manner compared with a normal control group (P<0.01), and the current amplitudes of CCI rats activated by the same concentrations of GABA (10−6-10−3 mol/l) were significantly decreased compared with the control group (P<0.05). The inward currents activated by 100 µmol/l GABA were suppressed by treatment with 1, 10 and 100 µmol/l NFA (5.32±3.51, 33.8±5.20, and 52.2±6.32%, respectively; P<0.05). The inverse potentials of GABA-induced currents were 9.87±1.32 and 9.64±1.24 mV with and without NFA, respectively (P<0.05). Pre-treatment with NFA exerted a strong inhibitory effect on the peak value of GABA-induced current, and the GABA-induced response was inhibited by the same concentrations of NFA (1, 10 and 100 µmol/l) in the control and CCI groups (P<0.05). The results suggest that NFA reduced the primary afferent depolarization (PAD) associated with neuropathic pain and mediated by the GABAA receptor. NFA may regulate neuropathic pain by inhibiting dorsal root reflexes, which are triggered PAD.
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Affiliation(s)
- Li-Jie Wang
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Yang Wang
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China.,The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China.,Department of Physiology, Wuhan University School of Basic Medical Sciences, Wuhan, Hubei 430071, P.R. China
| | - Meng-Jie Chen
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Zhen-Pu Tian
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Bi-Han Lu
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Ke-Tao Mao
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China.,The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Liang Zhang
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China.,The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Lei Zhao
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China.,The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Li-Ya Shan
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China.,The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Li Li
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China.,The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Jun-Qiang Si
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China.,The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China.,Department of Physiology, Wuhan University School of Basic Medical Sciences, Wuhan, Hubei 430071, P.R. China.,Department of Physiology, Huazhong University of Science and Technology, Wuhan, Hubei 430070, P.R. China
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7
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Low doses of tizanidine synergize the anti-nociceptive and anti-inflammatory effects of ketorolac or naproxen while reducing of side effects. Eur J Pharmacol 2017; 805:51-57. [DOI: 10.1016/j.ejphar.2017.03.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 03/07/2017] [Accepted: 03/13/2017] [Indexed: 01/15/2023]
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8
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The RS504393 Influences the Level of Nociceptive Factors and Enhances Opioid Analgesic Potency in Neuropathic Rats. J Neuroimmune Pharmacol 2017; 12:402-419. [PMID: 28337574 PMCID: PMC5527054 DOI: 10.1007/s11481-017-9729-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 02/13/2017] [Indexed: 12/19/2022]
Abstract
Increasing evidence has indicated that activated glial cells releasing nociceptive factors, such as interleukins and chemokines, are of key importance for neuropathic pain. Significant changes in the production of nociceptive factors are associated with the low effectiveness of opioids in neuropathic pain. Recently, it has been suggested that CCL2/CCR2 signaling is important for nociception. Here, we studied the time course changes in the mRNA/protein level of CD40/Iba-1, CCL2 and CCR2 in the spinal cord/dorsal root ganglia (DRG) in rats following chronic constriction injury (CCI) of the sciatic nerve. Moreover, we examined the influence of intrathecal preemptive and repeated (daily for 7 days) administration of RS504393, CCR2 antagonist, on pain-related behavior and the associated biochemical changes of some nociceptive factors as well as its influence on opioid effectiveness. We observed simultaneous upregulation of Iba-1, CCL2, CCR2 in the spinal cord on 7th day after CCI. Additionally, we demonstrated that repeated administration of RS504393 not only attenuated tactile/thermal hypersensitivity but also enhanced the analgesic properties of morphine and buprenorphine under neuropathy. Our results proof that repeated administration of RS504393 reduced the mRNA and/or protein levels of pronociceptive factors, such as IL-1beta, IL-18, IL-6 and inducible nitric oxide synthase (iNOS), and some of their receptors in the spinal cord and/or DRG. Furthermore, RS504393 elevated the spinal protein level of antinociceptive IL-1alpha and IL-18 binding protein. Our data provide new evidence that CCR2 is a promising target for diminishing neuropathic pain and enhancing the opioid analgesic effects.
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9
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Zhao L, Li LI, Ma KT, Wang Y, Li J, Shi WY, Zhu HE, Zhang ZS, Si JQ. NSAIDs modulate GABA-activated currents via Ca 2+-activated Cl - channels in rat dorsal root ganglion neurons. Exp Ther Med 2016; 11:1755-1761. [PMID: 27168798 PMCID: PMC4840517 DOI: 10.3892/etm.2016.3158] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 02/11/2016] [Indexed: 12/11/2022] Open
Abstract
The ability of non-steroidal anti-inflammatory drugs (NSAIDs) to modulate γ-aminobutyrate (GABA)-activated currents via Ca2+-activated Cl− channels in rat dorsal root ganglion neurons (DRG), was examined in the present study. During the preparation of DRG neurons harvested from Sprague-Dawley rats, the whole-cell recording technique was used to record the effect of NSAIDs on GABA-activated inward currents, and the expression levels of the TMEM16A and TMEM16B subunits were revealed. In the event that DRG neurons were pre-incubated for 20 sec with niflumic acid (NFA) and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) prior to the administration of GABA, the GABA-induced inward currents were diminished markedly in the majority of neurons examined (96.3%). The inward currents induced by 100 µmol/l GABA were attenuated by (0±0.09%; neurons = 4), (5.32±3.51%; neurons = 6), (21.3±4.00%; neurons = 5), (33.8±5.20%; neurons = 17), (52.2±5.10%; neurons = 4) and (61.1±4.12%; neurons = 12) by 0.1, 1, 3, 10, 30 and 100 µmol/l NFA, respectively. The inward currents induced by 100 µmol/l GABA were attenuated by (13.8±6%; neurons = 6), (23.2±14.7%; neurons = 6) and (29.7±9.1%; neurons = 9) by 3, 10 and 30 µmol/l NPPB, respectively. NFA and NPPB dose-dependently inhibited GABA-activated currents with half maximal inhibitory concentration (IC50) values of 6.7 and 11 µmol/l, respectively. The inhibitory effect of 100 µmol/l NFA on the GABA-evoked inward current were also strongly inhibited by nitrendipine (NTDP; an L-type calcium channel blocker), 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetrakis (a highly selective calcium chelating reagent), caffeine (a widely available Ca2+ consuming drug) and calcium-free extracellular fluid, in a concentration-dependent manner. Immunofluorescent staining indicated that TMEM16A and TMEM16B expression was widely distributed in DRG neurons. The results suggest that NSAIDs may be able to regulate Ca2+-activated chloride channels to reduce GABAA receptor-mediated inward currents in DRGs.
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Affiliation(s)
- Lei Zhao
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - L I Li
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Ke-Tao Ma
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Yang Wang
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Jing Li
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Wen-Yan Shi
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - H E Zhu
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Zhong-Shuang Zhang
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Jun-Qiang Si
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China; Department of Physiology, School of Basic Medical Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
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10
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Gu XY, Liu BL, Zang KK, Yang L, Xu H, Pan HL, Zhao ZQ, Zhang YQ. Dexmedetomidine inhibits Tetrodotoxin-resistant Nav1.8 sodium channel activity through Gi/o-dependent pathway in rat dorsal root ganglion neurons. Mol Brain 2015; 8:15. [PMID: 25761941 PMCID: PMC4350947 DOI: 10.1186/s13041-015-0105-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 02/18/2015] [Indexed: 11/12/2022] Open
Abstract
Background Systemically administered dexmedetomidine (DEX), a selective α2 adrenergic receptor (α2-AR) agonists, produces analgesia and sedation. Peripherally restricted α2-AR antagonist could block the analgesic effect of systemic DEX on neuropathic pain, with no effect on sedation, indicating peripheral analgesic effect of DEX. Tetrodotoxin-resistant (TTX-R) sodium channel Nav1.8 play important roles in the conduction of nociceptive sensation. Both α2-AR and Nav1.8 are found in small nociceptive DRG neurons. We, therefore, investigated the effects of DEX on the Nav1.8 currents in acutely dissociated small-diameter DRG neurons. Results Whole-cell patch-clamp recordings demonstrated that DEX concentration-dependently suppressed TTX-R Nav1.8 currents in small-diameter lumbar DRG neurons. DEX also shifted the steady-state inactivation curves of Nav1.8 in a hyperpolarizing direction and increased the threshold of action potential and decrease electrical and chemical stimuli-evoked firings in small-diameter DRG neurons. The α2-AR antagonist yohimbine or α2A-AR antagonist BRL44408 but not α2B-AR antagonist imiloxan blocked the inhibition of Nav1.8 currents by DEX. Immunohistochemistry results showed that Nav1.8 was predominantly expressed in peripherin-positive small-diameter DRG neurons, and some of them were α2A-AR-positive ones. Our electrophysiological recordings also demonstrated that DEX-induced inhibition of Nav1.8 currents was prevented by intracellular application of G-protein inhibitor GDPβ-s or Gi/o proteins inhibitor pertussis toxin (PTX), and bath application of adenylate cyclase (AC) activator forskolin or membrane-permeable cAMP analogue 8-Bromo-cAMP (8-Br-cAMP). PKA inhibitor Rp-cAMP could mimic DEX-induced inhibition of Nav1.8 currents. Conclusions We established a functional link between α2-AR and Nav1.8 in primary sensory neurons utilizing the Gi/o/AC/cAMP/PKA pathway, which probably mediating peripheral analgesia of DEX.
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Affiliation(s)
- Xi-Yao Gu
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
| | - Ben-Long Liu
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
| | - Kai-Kai Zang
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
| | - Liu Yang
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
| | - Hua Xu
- Department of Anesthesiology, Changhai Hospital, The Second Military Medical University, Shanghai, 200433, China.
| | - Hai-Li Pan
- Center for Neuropsychiatric Diseases, Institute of Life Science, Nanchang University, Nanchang, 330031, China.
| | - Zhi-Qi Zhao
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
| | - Yu-Qiu Zhang
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
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PKCɛ mediates substance P inhibition of GABAA receptors-mediated current in rat dorsal root ganglion. ACTA ACUST UNITED AC 2015; 35:1-9. [PMID: 25673185 DOI: 10.1007/s11596-015-1380-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/04/2014] [Indexed: 02/07/2023]
Abstract
The mechanism underlying the modulatory effect of substance P (SP) on GABA-activated response in rat dorsal root ganglion (DRG) neurons was investigated. In freshly dissociated rat DRG neurons, whole-cell patch-clamp technique was used to record GABA-activated current and sharp electrode intracellular recording technique was used to record GABA-induced membrane depolarization. Application of GABA (1-1000 μmol/L) induced an inward current in a concentration-dependent manner in 114 out of 127 DRG neurons (89.8 %) examined with whole-cell patch-clamp recordings. Bath application of GABA (1-1000 μmol/L) evoked a depolarizing response in 236 out of 257 (91.8%) DRG neurons examined with intracellular recordings. Application of SP (0.001-1 μmol/L) suppressed the GABA-activated inward current and membrane depolarization. The inhibitory effects were concentration-dependent and could be blocked by the selective neurokinin 1 (NK1) receptors antagonist spantide but not by L659187 and SR142801 (1 μmol/L, n=7), selective antagonists of NK2 and NK3. The inhibitory effect of SP was significantly reduced by the calcium chelator BAPTA-AM, phospholipase C (PLC) inhibitor U73122, and PKC inhibitor chelerythrine, respectively. The PKA inhibitor H-89 did not affect the SP effect. Remarkably, the inhibitory effect of SP on GABA-activated current was nearly completely removed by a selective PKCε inhibitor epilon-V1-2 but not by safingol and LY333531, selective inhibitors of PKCα and PKCβ. Our results suggest that NK1 receptor mediates SP-induced inhibition of GABA-activated current and membrane depolarization by activating intracellular PLC-Ca²⁺-PKCε cascade. SP might regulate the excitability of peripheral nociceptors through inhibition of the "pre-synaptic inhibition" evoked by GABA, which may explain its role in pain and neurogenic inflammation.
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