1. Mu and Delta Opioid Receptor Targeting Reduces Connexin 43-Based Heterocellular Coupling during Neuropathic Pain
- Author
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Nunzio Vicario, Simona Denaro, Rita Turnaturi, Lucia Longhitano, Federica Maria Spitale, Salvatore Spoto, Agostino Marrazzo, Agata Zappalà, Daniele Tibullo, Giovanni Li Volti, Santina Chiechio, Lorella Pasquinucci, Rosalba Parenti, and Carmela Parenti
- Subjects
Receptors, Opioid, mu ,microglia ,Opioid ,Catalysis ,Inorganic Chemistry ,delta ,astrocyte ,chronic constriction injury ,MOR ,DOR ,inflammation ,Receptors, Opioid, delta ,Receptors ,Humans ,Physical and Theoretical Chemistry ,Molecular Biology ,Spectroscopy ,Analgesics ,Organic Chemistry ,General Medicine ,Computer Science Applications ,Analgesics, Opioid ,Spinal Cord ,mu ,Hyperalgesia ,Connexin 43 ,Receptors, Opioid ,Neuralgia - Abstract
Chronic neuropathic pain emerges from either central or peripheral lesions inducing spontaneous or amplified responses to non-noxious stimuli. Despite different pharmacological approaches to treat such a chronic disease, neuropathic pain still represents an unmet clinical need, due to long-term therapeutic regimens and severe side effects that limit application of currently available drugs. A critical phenomenon involved in central sensitization is the exchange of signalling molecules and cytokines, between glia and neurons, driving the chronicization process. Herein, using a chronic constriction injury (CCI) model of neuropathic pain, we evaluated the efficacy of the mu (M-) and delta (D-) opioid receptor (-OR) targeting agent LP2 in modulating connexin-based heterocellular coupling and cytokine levels. We found that long-term efficacy of LP2 is consequent to MOR-DOR targeting resulting in the reduction of CCI-induced astrocyte-to-microglia heterocellular coupling mediated by connexin 43. We also found that single targeting of DOR reduces TNF and IL-6 levels in the chronic phase of the disease, but the peripheral and central discharge as the primary source of excitotoxic stimulation in the spinal cord requires a simultaneous MOR-DOR targeting to reduce CCI-induced neuropathic pain.
- Published
- 2022