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Acute visceral pain relief mediated by A3AR agonists in rats: involvement of N-type voltage-gated calcium channels. Pain 2021; 161:2179-2190. [PMID: 32379223 DOI: 10.1097/j.pain.0000000000001905] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/14/2020] [Indexed: 02/07/2023]
Abstract
ABSTRACT Pharmacological tools for chronic visceral pain management are still limited and inadequate. A3 adenosine receptor (A3AR) agonists are effective in different models of persistent pain. Recently, their activity has been related to the block of N-type voltage-gated Ca2+ channels (Cav2.2) in dorsal root ganglia (DRG) neurons. The present work aimed to evaluate the efficacy of A3AR agonists in reducing postinflammatory visceral hypersensitivity in both male and female rats. Colitis was induced by the intracolonic instillation of 2,4-dinitrobenzenesulfonic acid (DNBS; 30 mg in 0.25 mL 50% EtOH). Visceral hypersensitivity was assessed by measuring the visceromotor response and the abdominal withdrawal reflex to colorectal distension. The effects of A3AR agonists (MRS5980 and Cl-IB-MECA) were evaluated over time after DNBS injection and compared to that of the selective Cav2.2 blocker PD173212, and the clinically used drug linaclotide. A3AR agonists significantly reduced DNBS-evoked visceral pain both in the postinflammatory (14 and 21 days after DNBS injection) and persistence (28 and 35 days after DNBS) phases. Efficacy was comparable to effects induced by linaclotide. PD173212 fully reduced abdominal hypersensitivity to control values, highlighting the role of Cav2.2. The effects of MRS5980 and Cl-IB-MECA were completely abolished by the selective A3AR antagonist MRS1523. Furthermore, patch-clamp recordings showed that A3AR agonists inhibited Cav2.2 in dorsal root ganglia neurons isolated from either control or DNBS-treated rats. The effect on Ca2+ current was PD173212-sensitive and prevented by MRS1523. A3AR agonists are effective in relieving visceral hypersensitivity induced by DNBS, suggesting a potential therapeutic role against abdominal pain.
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Chen C, Xu B, Shi X, Zhang M, Zhang Q, Zhang T, Zhao W, Zhang R, Wang Z, Li N, Fang Q. GpTx-1 and [Ala 5 , Phe 6 , Leu 26 , Arg 28 ]GpTx-1, two peptide Na V 1.7 inhibitors: analgesic and tolerance properties at the spinal level. Br J Pharmacol 2018; 175:3911-3927. [PMID: 30076786 DOI: 10.1111/bph.14461] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 07/10/2018] [Accepted: 07/13/2018] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE The voltage-gated sodium channel NaV 1.7 is considered a therapeutic target for pain treatment based on human genetic evidence. GpTx-1 and its potent analogue [Ala5 , Phe6 , Leu26 , Arg28 ]GpTx-1 (GpTx-1-71) were recently characterized as NaV 1.7 inhibitors in vitro. Furthermore, the present work was conducted to investigate the analgesic properties of these two peptides in different pain models after spinal administration. EXPERIMENTAL APPROACH The antinociceptive activities of both GpTx-1 and GpTx-1-71 were investigated in mouse models of acute, visceral, inflammatory and neuropathic pain. Furthermore, the side effects of GpTx-1 and GpTx-1-71 were evaluated in rotarod, antinociceptive tolerance, acute hyperlocomotion and gastrointestinal transit tests. KEY RESULTS The i.t. administration of both GpTx-1 and GpTx-1-71 dose-dependently produced powerful antinociception in the different pain models. This effect was attenuated by the opioid receptor antagonist naloxone, suggesting the involvement of the opioid system. In this study, repeated administration of these two_peptides produced spinal analgesia without a loss of potency over 8 days in mouse models of acute, inflammatory and neuropathic pain. Moreover, spinal administration of GpTx-1 and GpTx-1-71 did not induce significant effects on motor coordination, evoke acute hyperlocomotion or increase gastrointestinal transit time. CONCLUSIONS AND IMPLICATIONS Our data indicate that the NaV 1.7 peptide inhibitors GpTx-1 and GpTx-1-71 produce powerful, nontolerance-forming analgesia in preclinical pain models, which might be dependent on the endogenous opioid system. In addition, at the spinal level, the limited side effects imply that these NaV 1.7 peptide inhibitors could be potentially developed as GpTx-1-based drugs for pain relief.
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Affiliation(s)
- Chao Chen
- Guangdong Provincial Key Laboratory of Nano-Micro Materials Research, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Biao Xu
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Xuerui Shi
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Mengna Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Qinqin Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Ting Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Weidong Zhao
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Run Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Zilong Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Ning Li
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Quan Fang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
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Tallarida RJ, Porreca F, Cowan A. Statistical analysis of drug-drug and site-site interactions with isobolograms. Life Sci 1989; 45:947-61. [PMID: 2677570 DOI: 10.1016/0024-3205(89)90148-3] [Citation(s) in RCA: 284] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The use of more than one drug to achieve a desired effect has been a common practice in pharmacologic testing and in clinical practice. For example, combinations of analgesics are frequently prescribed with a view to enhancing pain relief and reducing adverse effects. It is also well established that administration of more than one drug may give effects that are greater than, or less than, the additive effect of each drug given individually. A non-mechanistic method of characterizing the effect resulting from the administration of two compounds is the isobologram. It is relatively simple to draw and interpret isobolograms. However, this graphical technique, which employs equieffective concentrations of individual drugs and combinations of these, obtains the concentrations as random variables from concentration-effect data, usually transformed to a parallel line assay. Thus, statistical confidence limits from such assays, as well as from non-parallel designs, must be expressed on the isobologram if this diagram is to establish superadditive, subadditive, or merely additive effects. We now present a detailed statistical analysis of the isobolographic method illustrated with examples of the statistical procedures, a rational basis for selecting proportions of each drug in the combination, and a relatively novel application of the isobolographic concept, i.e., interactions involving different anatomical sites.
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Affiliation(s)
- R J Tallarida
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
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