1. To gain further insight into the mechanisms underlying the antihyperalgesic and antiallodynic actions of gabapentin, a chronic pain model was prepared by partially ligating the sciatic nerve in mice. The mice then received systemic or local injections of gabapentin combined with either central noradrenaline (NA) depletion by 6-hydroxydopamine (6-OHDA) or alpha-adrenergic receptor blockade. 2. Intraperitoneally (i.p.) administered gabapentin produced antihyperalgesic and antiallodynic effects that were manifested by elevation of the withdrawal threshold to a thermal (plantar test) or mechanical (von Frey test) stimulus, respectively. 3. Similar effects were obtained in both the plantar and von Frey tests when gabapentin was injected intracerebroventricularly (i.c.v.) or intrathecally (i.t.), suggesting that it acts at both supraspinal and spinal loci. This novel supraspinal analgesic action of gabapentin was only obtained in ligated neuropathic mice, and gabapentin (i.p. and i.c.v.) did not affect acute thermal and mechanical nociception. 4. In mice in which central NA levels were depleted by 6-OHDA, the antihyperalgesic and antiallodynic effects of i.p. and i.c.v. gabapentin were strongly suppressed. 5. The antihyperalgesic and antiallodynic effects of systemic gabapentin were reduced by both systemic and i.t. administration of yohimbine, an alpha2-adrenergic receptor antagonist. By contrast, prazosin (i.p. or i.t.), an alpha1-adrenergic receptor antagonist, did not alter the effects of gabapentin. 6. It was concluded that the antihyperalgesic and antiallodynic effects of gabapentin are mediated substantially by the descending noradrenergic system, resulting in the activation of spinal alpha2-adrenergic receptors.
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http://dx.doi.org/10.1038/sj.bjp.0706109 | DOI Listing |
Biomed Pharmacother
December 2024
Laboratory 7, "Pain and Analgesia", Department of Pharmacobiology, Center for Research and Advanced Studies (CINVESTAV), Sede Sur, Mexico City, Mexico.
The efficacy of opioids in the treatment of chronic pain is limited; however, the adverse effects they produce are considerable. N-palmitoylethanolamide (PEA), a bioactive lipid mediator with structural similarities to endocannabinoids, has exhibited notable anti-inflammatory and analgesic effects in preclinical models. The objective of this study was to investigate the antinociceptive properties, motor coordination (MC), and constipation effects of tramadol and PEA in combination within a neuropathic pain model.
View Article and Find Full Text PDFChem Biol Interact
November 2024
Department of Pharmacology and Zhejiang Key Lab of Pathophysiology, Ningbo University, Health Science Center, Ningbo, Zhejiang Province, China. Electronic address:
A substantial proportion of diabetic patients suffer a debilitating and persistent pain state, known as peripheral painful neuropathy that necessitates improved therapy or antidote. Decursin, a major active ingredient from Angelica gigas Nakai, has been reported to possess antidepressant activity in preclinical studies. As antidepressants have been typically used as standard agents against persistent neuropathic pain, this study aimed to probe the effect of decursin on neuropathic pain associated with streptozotocin-induced type 1 diabetes in male C57BL6J mice.
View Article and Find Full Text PDFNeuropharmacology
August 2024
Department of Pharmacology, Faculty of Pharmacy, Anadolu University, 26470, Eskisehir, Turkey. Electronic address:
This research aims to investigate the possible antiallodynic and antihyperalgesic effects of pure vitexin and vitexin-loaded solid lipid nanoparticles (SLN) on neuropathic pain and the pathways mediating these effects. Chronic constriction nerve injury was induced in female rats, and the effects of vitexin at the doses of 5, 10, 20, 40 mg/kg were evaluated. Ketanserin, ondansetron, WAY-100635, yohimbine and bicuculin, which are antagonists of receptors on pain pathways.
View Article and Find Full Text PDFBiomed Pharmacother
May 2024
Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional (IPN), Ciudad de México, Mexico. Electronic address:
This study evaluates the antiallodynic and antihyperalgesic effects of LMH-2, a new haloperidol (HAL) analog that acts as sigma-1 receptor (σ1 R) antagonist, in diabetic mice using a model of neuropathic pain induced by chronic hyperglycemia. Additionally, we compared its effects with those of HAL. Hyperglycemia was induced in mice by nicotinamide-streptozotocin administration (NA-STZ, 50-130 mg/kg).
View Article and Find Full Text PDFDrug Dev Res
February 2024
Departamento de Sistemas Biológicos, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Xochimilco, Coyoacan, Mexico.
The study aimed to examine the effect of intraperitoneal and intrathecal (±)-licarin A in neuropathic pain induced by L5 and L6 spinal nerve ligation (SNL) in male Wistar rats and the possible involvement of the NO-cGMP-ATP-sensitive K channel pathway. Neuropathic pain signs (allodynia and hyperalgesia) were evaluated on postoperative Day 14 using von Frey filaments. Single intraperitoneal (0.
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