Peripheral sensitization in migraine—role for P2X purinergic receptors in the dura–vascular sensory pathway

2007 ◽  
Vol 68 (6) ◽  
pp. 321-328 ◽  
Author(s):  
Ernest A. Jennings ◽  
Hyun-jung Cho
Author(s):  
Lili Pan ◽  
Yu Ma ◽  
Yunchun Li ◽  
Haoxing Wu ◽  
Rui Huang ◽  
...  

Abstract:: Recent studies have proven that the purinergic signaling pathway plays a key role in neurotransmission and neuromodulation, and is involved in various neurodegenerative diseases and psychiatric disorders. With the characterization of the subtypes of receptors in purinergic signaling, i.e. the P1 (adenosine), P2X (ion channel) and P2Y (G protein-coupled), more attentions were paid to the pathophysiology and therapeutic potential of purinergic signaling in central nervous system disorders. Alzheimer’s disease (AD) is a progressive and deadly neurodegenerative disease that is characterized by memory loss, cognitive impairment and dementia. However, as drug development aimed to prevent or control AD follows a series of failures in recent years, more researchers focused on the neuroprotection-related mechanisms such as purinergic signaling in AD patients to find a potential cure. This article reviews the recent discoveries of purinergic signaling in AD, summaries the potential agents as modulators for the receptors of purinergic signaling in AD related research and treatments. Thus, our paper provided an insight for purinergic signaling in the development of anti-AD therapies.


2021 ◽  
Vol 4 (Supplement_1) ◽  
pp. 278-279
Author(s):  
M Defaye ◽  
N Abdullah ◽  
M Iftinca ◽  
C Altier

Abstract Background Long-lasting changes in neural pain circuits precipitate the transition from acute to chronic pain in patients living with inflammatory bowel diseases (IBDs). While significant improvement in IBD therapy has been made to reduce inflammation, a large subset of patients continues to suffer throughout quiescent phases of the disease, suggesting a high level of plasticity in nociceptive circuits during acute phases. The establishment of chronic visceral pain results from neuroplasticity in nociceptors first, then along the entire neural axis, wherein microglia, the resident immune cells of the central nervous system, are critically involved. Our lab has shown that spinal microglia were key in controlling chronic pain state in IBD. Using the Dextran Sodium Sulfate (DSS) model of colitis, we found that microglial G-CSF was able to sensitize colonic nociceptors that express the pain receptor TRPV1. While TRPV1+ nociceptors have been implicated in peripheral sensitization, their contribution to central sensitization via microglia remains unknown. Aims To investigate the role of TRPV1+ visceral afferents in microglial activation and chronic visceral pain. Methods We generated DREADD (Designer Receptors Exclusively Activated by Designer Drugs) mice in which TRPV1 sensory neurons can be inhibited (TRPV1-hM4Di) or activated (TRPV1-hM3Dq) in a time and tissue specific manner using the inert ligand Clozapine-N-Oxide (CNO). To test the inhibition of TRPV1 neurons in DSS-induced colitis, TRPV1-hM4Di mice were treated with DSS 2.5% or water for 7 days and received vehicle or CNO i.p. injection twice daily. To activate TRPV1 visceral afferents, TRPV1-hM3Dq mice received vehicle or CNO daily for 7 days, by oral gavage. After 7 days of treatment, visceral pain was evaluated by colorectal distension and spinal cords tissues were harvested to measure microglial activation. Results Our data validated the nociceptor specific expression and function of the DREADD in TRPV1-Cre mice. Inhibition of TRPV1 visceral afferents in DSS TRPV1-hM4Di mice was able to prevent the colitis-induced microglial activation and thus reduce visceral hypersensitivity. In contrast, activation of TRPV1 visceral afferents in TRPV1-hM3Dq mice was sufficient to drive microglial activation in the absence of colitis. Analysis of the proalgesic mediators derived from activated TRPV1-hM3Dq neurons identified ATP as a key factor of microglial activation. Conclusions Overall, these data provide novel insights into the mechanistic understanding of the gut/brain axis in chronic visceral pain and suggest a role of purinergic signaling that could be harnessed for testing effective therapeutic approaches to relieve pain in IBD patients. Funding Agencies CCCACHRI (Alberta Children’s Hospital Research Institute) and CSM (Cumming School of Medicine) postdoctoral fellowship


Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 450
Author(s):  
Magdalena Kocot-Kępska ◽  
Renata Zajączkowska ◽  
Joanna Mika ◽  
David J. Kopsky ◽  
Jerzy Wordliczek ◽  
...  

Neuropathic pain in humans results from an injury or disease of the somatosensory nervous system at the peripheral or central level. Despite the considerable progress in pain management methods made to date, peripheral neuropathic pain significantly impacts patients’ quality of life, as pharmacological and non-pharmacological methods often fail or induce side effects. Topical treatments are gaining popularity in the management of peripheral neuropathic pain, due to excellent safety profiles and preferences. Moreover, topical treatments applied locally may target the underlying mechanisms of peripheral sensitization and pain. Recent studies showed that peripheral sensitization results from interactions between neuronal and non-neuronal cells, with numerous signaling molecules and molecular/cellular targets involved. This narrative review discusses the molecular/cellular mechanisms of drugs available in topical formulations utilized in clinical practice and their effectiveness in clinical studies in patients with peripheral neuropathic pain. We searched PubMed for papers published from 1 January 1995 to 30 November 2020. The key search phrases for identifying potentially relevant articles were “topical AND pain”, “topical AND neuropathic”, “topical AND treatment”, “topical AND mechanism”, “peripheral neuropathic”, and “mechanism”. The result of our search was 23 randomized controlled trials (RCT), 9 open-label studies, 16 retrospective studies, 20 case (series) reports, 8 systematic reviews, 66 narrative reviews, and 140 experimental studies. The data from preclinical studies revealed that active compounds of topical treatments exert multiple mechanisms of action, directly or indirectly modulating ion channels, receptors, proteins, and enzymes expressed by neuronal and non-neuronal cells, and thus contributing to antinociception. However, which mechanisms and the extent to which the mechanisms contribute to pain relief observed in humans remain unclear. The evidence from RCTs and reviews supports 5% lidocaine patches, 8% capsaicin patches, and botulinum toxin A injections as effective treatments in patients with peripheral neuropathic pain. In turn, single RCTs support evidence of doxepin, funapide, diclofenac, baclofen, clonidine, loperamide, and cannabidiol in neuropathic pain states. Topical administration of phenytoin, ambroxol, and prazosin is supported by observational clinical studies. For topical amitriptyline, menthol, and gabapentin, evidence comes from case reports and case series. For topical ketamine and baclofen, data supporting their effectiveness are provided by both single RCTs and case series. The discussed data from clinical studies and observations support the usefulness of topical treatments in neuropathic pain management. This review may help clinicians in making decisions regarding whether and which topical treatment may be a beneficial option, particularly in frail patients not tolerating systemic pharmacotherapy.


Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 309
Author(s):  
Lijing Yang ◽  
Mengjia Hu ◽  
Yukai Lu ◽  
Songling Han ◽  
Junping Wang

Hematopoietic stem cells (HSCs) regularly produce various blood cells throughout life via their self-renewal, proliferation, and differentiation abilities. Most HSCs remain quiescent in the bone marrow (BM) and respond in a timely manner to either physiological or pathological cues, but the underlying mechanisms remain to be further elucidated. In the past few years, accumulating evidence has highlighted an intermediate role of inflammasome activation in hematopoietic maintenance, post-hematopoietic transplantation complications, and senescence. As a cytosolic protein complex, the inflammasome participates in immune responses by generating a caspase cascade and inducing cytokine secretion. This process is generally triggered by signals from purinergic receptors that integrate extracellular stimuli such as the metabolic factor ATP via P2 receptors. Furthermore, targeted modulation/inhibition of specific inflammasomes may help to maintain/restore adequate hematopoietic homeostasis. In this review, we will first summarize the possible relationships between inflammasome activation and homeostasis based on certain interesting phenomena. The cellular and molecular mechanism by which purinergic receptors integrate extracellular cues to activate inflammasomes inside HSCs will then be described. We will also discuss the therapeutic potential of targeting inflammasomes and their components in some diseases through pharmacological or genetic strategies.


1996 ◽  
Vol 24 (4) ◽  
pp. 560S-560S
Author(s):  
Davide Ferrari ◽  
Martin Villalba ◽  
Paola Chiozzi ◽  
Monica Dal Susino ◽  
Simonetta Falzoni ◽  
...  

Cephalalgia ◽  
1984 ◽  
Vol 4 (4) ◽  
pp. 243-251 ◽  
Author(s):  
Milena De Marinis ◽  
Nicola Martucci ◽  
Franco Maria Gagliardi ◽  
Massimo Feliciani ◽  
Alessandro Agnoli

It has been hypothesized that the trigeminal system may control vasomotor changes and pain in vascular headaches. In this study, headache was induced by an intravenous injection of histamine in 37 patients with trigeminal rhizotomy and in 12 controls. The vasomotor response to histamine was studied with facial telethermography. The headache in patients with trigeminal lesions differed, in a prevalence of unilateral localization contralaterally to the operated side (21 patients), from that in controls. No relationship was found between the hypoesthesia caused by the operation and the prevalence of unilateral headache. A statistically significant correlation ( p < 0.001) was found between unilateral absence of headache and decreased vasomotor response on the operated side. These reactions occurred more in patients who underwent thermocoagulation than in patients who underwent retro-gasserian rhizotomy. Thus the gasserian ganglion seems to control the cranio-facial vasomotor response and the headache through a vascular pathway, acting on cerebral arteries, which differs from the sensory pathway.


2005 ◽  
Vol 289 (5) ◽  
pp. L890-L895 ◽  
Author(s):  
Cara Geary ◽  
Henry Akinbi ◽  
Tom Korfhagen ◽  
Jean-Etienne Fabre ◽  
Richard Boucher ◽  
...  

Purinergic receptors are expressed throughout the respiratory system in diverse cell types. The efficiency of mucus clearance in the airways, the cascade leading to tissue injury, and inflammation are modulated by autocrine/paracrine release of nucleotides and signaling by purinergic receptors. We assessed the role of purinergic receptors in innate host defense of the lung in vivo by infecting mice deficient in P2Y1, P2Y2, or both receptors with intratracheal instillation of Pseudomonas aeruginosa. After P. aeruginosa challenge, all double knockout (P2Y1/P2Y2−/−) mice succumbed within 30 h of challenge, whereas 85% of the wild-type mice survived. Thirty-three percent of wild-type mice survived beyond 96 h. Single knockout mice, P2Y1−/−, or P2Y2−/−, exhibited intermediate survivals. Twenty-four hours following intratracheal instillation of a sublethal dose of P. aeruginosa, the level of total protein in bronchoalveolar lavage fluid was 1.8-fold higher in double knockout than in wild-type mice ( P < 0.04). Total cell count in bronchoalveolar lavage fluids at 4 h and levels of IL-6 and macrophage inflammatory protein-2 in lung homogenates at 24 h postchallenge were significantly reduced in P2Y1/P2Y2−/− mice relative to wild-type mice. These findings suggest that purinergic receptors exert a protective role against infection of the lungs by P. aeruginosa by decreasing protein leak and enhancing proinflammatory cytokine response.


Sign in / Sign up

Export Citation Format

Share Document