Ultra-low dose naloxone restores the antinocicepitve effect of morphine in PTX-treated rats: Association of IL-10 upregulation in the spinal cord

Targeting Cytokines for Morphine Tolerance: A Narrative Review

BACKGROUND

Despite its various side effects, morphine has been widely used in clinics for decades due to its powerful analgesic effect. Morphine tolerance is one of the major side effects, hindering its long-term usage for pain therapy. Currently, the thorough cellular and molecular mechanisms underlying morphine tolerance remain largely uncertain.

METHODS

We searched the PubMed database with Medical subject headings (MeSH) including 'morphine tolerance', 'cytokines', 'interleukin 1', 'interleukin 1 beta', 'interleukin 6', 'tumor necrosis factor alpha', 'interleukin 10', 'chemokines'. Manual searching was carried out by reviewing the reference lists of relevant studies obtained from the primary search. The searches covered the period from inception to November 1, 2017.

RESULTS

The expression levels of certain chemokines and pro-inflammatory cytokines were significantly increased in animal models of morphine tolerance. Cytokines and cytokine receptor antagonist showed potent effect of alleviating the development of morphine tolerance.

CONCLUSION

Cytokines play a fundamental role in the development of morphine tolerance. Therapeutics targeting cytokines may become alternative strategies for the management of morphine tolerance.

Transmission pathways and mediators as the basis for clinical pharmacology of pain

INTRODUCTION

Mediators in pain transmission are the targets of a multitude of different analgesic pharmaceuticals. This review explores the most significant mediators of pain transmission as well as the pharmaceuticals that act on them. Areas covered: The review explores many of the key mediators of pain transmission. In doing so, this review uncovers important areas for further research. It also highlights agents with potential for producing novel analgesics, probes important interactions between pain transmission pathways that could contribute to synergistic analgesia, and emphasizes transmission factors that participate in transforming acute injury into chronic pain. Expert commentary: This review examines current pain research, particularly in the context of identifying novel analgesics, highlighting interactions between analgesic transmission pathways, and discussing factors that may contribute to the development of chronic pain after an acute injury.

Clonal differences in IgE antibodies affect cutaneous anaphylaxis-associated thermal sensitivity in mice

Cellular and molecular mediators of immune responses are increasingly implicated in acute and chronic pain pathophysiologies. Here we demonstrate that passive cutaneous IgE/Ag anaphylaxis provokes increased thermal sensitivity in the hind paw tissue of mice. The murine anti-DNP IgE antibodies SPE-7 and ɛ26 are known to induce differential cytokine production in bone marrow cultured mast cells in vitro without antigen challenge. We found a novel, antigen-dependent heterogeneity in the thermal pain responses elicited in the hind paws between SPE-7 and ɛ26 sensitized DNP-challenged mice. Mice experienced pronounced hind paw thermal sensitivity lasting 6h after DNP challenge when sensitized with SPE-7 but not ɛ26 IgE. The two IgE clones induced equivalent hind paw edema, neutrophil influx, cytokine production, and reduction in tissue histamine content in vivo, and bound to the same or overlapping epitopes on the DNP antigen in vitro. Therefore IgE antibodies against the same antigen can induce comparable inflammation, yet contribute to markedly different anaphylaxis-associated pain within an allergic response, suggesting that non-canonical IgE binding partners such as sensory neurons may play a role in allergy-related pain responses.

Endogenous opiates and behavior: 2012

This paper is the thirty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2012 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).