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Antunes FTT, Huang S, Chen L, Zamponi GW. Effect of ABT-639 on Cav3.2 channel activity and its analgesic actions in mouse models of inflammatory and neuropathic pain. Eur J Pharmacol 2024; 967:176416. [PMID: 38342359 DOI: 10.1016/j.ejphar.2024.176416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/13/2024]
Abstract
Cav3.2 T-type calcium channels are important targets for pain relief in rodent models of inflammatory and neuropathic pain. Even though many T-type channel blockers have been tested in mice, only one molecule, ABT-639, has been tested in phase II clinical studies and did not produce analgesic effects over placebo. Here we examined the effects of ABT-639 on Cav3.2 channel activity in tsA-201 cells and dorsal root ganglion (DRG) neurons, in comparison with another established Cav3.2 inhibitor Z944. These experiments revealed that Z944 mediated ∼100-fold more potent inhibition of Cav3.2 currents than ABT-639, with the latter blocking channel activity by less than 15 percent when applied at a concentration of 30 μM. A slight increase in ABT-639 potency was observed at more depolarized holding potentials, suggesting that this compound may act preferentially on inactivated channels. We tested the effects of both compounds in the Complete Freund's Adjuvant (CFA) model of chronic inflammatory pain, and in partial sciatic nerve injury model of neuropathic pain in mice. In the neuropathic pain model, both Z944 and ABT-639 reversed mechanical hypersensitivity to similar degrees when delivered systemically, but remarkably, when delivered intrathecally, only Z944 was effective. In the CFA model, both compounds reversed thermal hyperalgesia upon systemic delivery, but only Z944 mediated pain relief upon intrathecal delivery, indicating that ABT-639 acts primarily at peripheral sites. ABT-639 lost its analgesic effects in CFA treated Cav3.2 null mice, indicating that these channels are essential for ABT-639-mediated pain relief despite its poor inhibition of Cav3.2 currents.
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Affiliation(s)
- Flavia Tasmin Techera Antunes
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, AB, T2N 4N1, Calgary, Canada
| | - Sun Huang
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, AB, T2N 4N1, Calgary, Canada
| | - Lina Chen
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, AB, T2N 4N1, Calgary, Canada
| | - Gerald W Zamponi
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, AB, T2N 4N1, Calgary, Canada.
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Parnell J, Martin N, Dedek A, Rudyk C, Landrigan J, Bellavance J, VanDerLoo S, Tsai EC, Hildebrand ME. Cannabinoid CB1 Receptor Expression and Localization in the Dorsal Horn of Male and Female Rat and Human Spinal Cord. Can J Pain 2023; 7:2264895. [PMID: 38170158 PMCID: PMC10761112 DOI: 10.1080/24740527.2023.2264895] [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: 07/31/2023] [Accepted: 09/26/2023] [Indexed: 01/05/2024]
Abstract
Background Preclinical and clinical evidence suggests that cannabis has potential analgesic properties. However, cannabinoid receptor expression and localization within spinal cord pain processing circuits remain to be characterized across sex and species. Aims We aimed to investigate the differential expression of the cannabinoid type 1 (CB1) receptor across dorsal horn laminae and cell populations in male and female adult rats and humans. Methods To investigate and quantify CB1 receptor expression in the spinal dorsal horn across species, we refined immunohistochemical procedures for successful rat and human fixed tissue staining and confocal imaging. Immunohistochemical results were complemented with analysis of CB1 gene (CNR1) expression within rodent and human dorsal horn using single-cell/nuclei RNA sequencing data sets. Results We found that CB1 was preferentially localized to the neuropil within the superficial dorsal horn of both rats and humans, with CB1 somatic staining across dorsal horn laminae. CB1 receptor immunoreactivity was significantly higher in the superficial dorsal horn compared to the deeper dorsal horn laminae for both rats and humans, which was conserved across sex. Interestingly, we found that CB1 immunoreactivity was not primarily localized to peptidergic afferents in rats and humans and that CNR1 (CB1) but not CNR2 (CB2) was robustly expressed in dorsal horn neuron subpopulations of both rodents and humans. Conclusions The conserved preferential expression of CB1 receptors in the superficial dorsal horn in male and female rodents and humans has significant implications for understanding the roles of this cannabinoid receptor in spinal mechanisms of nociception and analgesia.
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Affiliation(s)
- Jessica Parnell
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Newton Martin
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Annemarie Dedek
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Christopher Rudyk
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Jeffrey Landrigan
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Justin Bellavance
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Simon VanDerLoo
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Eve C. Tsai
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, Ontario, Canada
- Division of Neurosurgery, Department of Surgery, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Michael E. Hildebrand
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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Nunn AVW, Guy GW, Bell JD. Informing the Cannabis Conjecture: From Life's Beginnings to Mitochondria, Membranes and the Electrome-A Review. Int J Mol Sci 2023; 24:13070. [PMID: 37685877 PMCID: PMC10488084 DOI: 10.3390/ijms241713070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/15/2023] [Accepted: 08/17/2023] [Indexed: 09/10/2023] Open
Abstract
Before the late 1980s, ideas around how the lipophilic phytocannabinoids might be working involved membranes and bioenergetics as these disciplines were "in vogue". However, as interest in genetics and pharmacology grew, interest in mitochondria (and membranes) waned. The discovery of the cognate receptor for tetrahydrocannabinol (THC) led to the classification of the endocannabinoid system (ECS) and the conjecture that phytocannabinoids might be "working" through this system. However, the how and the "why" they might be beneficial, especially for compounds like CBD, remains unclear. Given the centrality of membranes and mitochondria in complex organisms, and their evolutionary heritage from the beginnings of life, revisiting phytocannabinoid action in this light could be enlightening. For example, life can be described as a self-organising and replicating far from equilibrium dissipating system, which is defined by the movement of charge across a membrane. Hence the building evidence, at least in animals, that THC and CBD modulate mitochondrial function could be highly informative. In this paper, we offer a unique perspective to the question, why and how do compounds like CBD potentially work as medicines in so many different conditions? The answer, we suggest, is that they can modulate membrane fluidity in a number of ways and thus dissipation and engender homeostasis, particularly under stress. To understand this, we need to embrace origins of life theories, the role of mitochondria in plants and explanations of disease and ageing from an adaptive thermodynamic perspective, as well as quantum mechanics.
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Affiliation(s)
- Alistair V. W. Nunn
- Research Centre for Optimal Health, Department of Life Sciences, University of Westminster, London W1W 6UW, UK; (G.W.G.); (J.D.B.)
- The Guy Foundation, Beaminster DT8 3HY, UK
| | - Geoffrey W. Guy
- Research Centre for Optimal Health, Department of Life Sciences, University of Westminster, London W1W 6UW, UK; (G.W.G.); (J.D.B.)
- The Guy Foundation, Beaminster DT8 3HY, UK
| | - Jimmy D. Bell
- Research Centre for Optimal Health, Department of Life Sciences, University of Westminster, London W1W 6UW, UK; (G.W.G.); (J.D.B.)
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Martins DF, Sorrentino V, Mazzardo-Martins L, Reed WR, Santos ARS, Gadotti VM, Zamponi GW. Antihyperalgesic effect of joint mobilization requires Cav3.2 calcium channels. Mol Brain 2023; 16:60. [PMID: 37464359 PMCID: PMC10355051 DOI: 10.1186/s13041-023-01049-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 07/12/2023] [Indexed: 07/20/2023] Open
Abstract
The present study was undertaken to explore the relative contributions of Cav3.2 T-type channels to mediating the antihyperalgesic activity of joint manipulation (JM) therapy. We used the chronic constriction injury model (CCI) to induce peripheral neuropathy and chronic pain in male mice, followed by JM. We demonstrate that JM produces long-lasting mechanical anti-hyperalgesia that is abolished in Cav3.2 null mice. Moreover, we found that JM displays a similar analgesic profile as the fatty acid amide hydrolase inhibitor URB597, suggesting a possible converging mechanism of action involving endocannabinoids. Overall, our findings advance our understanding of the mechanisms through which JM produces analgesia.
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Affiliation(s)
- Daniel F Martins
- Experimental Neuroscience Laboratory (LaNEx), Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Palhoça, SC, Brazil
- Programa de Pós-Graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário-Trindade, Florianópolis, SC, Brazil
| | - Victor Sorrentino
- Experimental Neuroscience Laboratory (LaNEx), Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Palhoça, SC, Brazil
| | - Leidiane Mazzardo-Martins
- Experimental Neuroscience Laboratory (LaNEx), Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Palhoça, SC, Brazil
- Programa de Pós-Graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário-Trindade, Florianópolis, SC, Brazil
| | - William R Reed
- Department of Physical Therapy, Rehabilitation Science Program, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Adair R S Santos
- Programa de Pós-Graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário-Trindade, Florianópolis, SC, Brazil
| | - Vinícius M Gadotti
- Departments of Clinical Neurosciences, and Physiology & Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Gerald W Zamponi
- Departments of Clinical Neurosciences, and Physiology & Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada.
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