The utility of morphine for the treatment of chronic pain is limited by the development of analgesic tolerance. Adenylyl cyclase (AC) superactivation, induced by chronic opioid agonist administration, is regarded as one of the molecular mechanisms leading to tolerance. In the present work, we tested the role of Raf-1 in morphine-mediated AC superactivation in CHO cells stably expressing the human micro-opioid receptor. We found that pretreatment of CHO cells stably expressing the human micro-opioid receptor with the selective Raf-1 inhibitor, 3-(3,5-dibromo-4-hydroxybenzylidene)-5-iodo-1,3-dihydroindol-2-one (GW5074, 10 microM, 60 min) completely abolished chronic morphine-mediated AC superactivation (P < 0.01). This finding indicates that Raf-1 may have a crucial role in compensatory feedback regulation of cellular cAMP levels by clinically important opioid analgesics.
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http://dx.doi.org/10.1016/j.ejphar.2006.04.033 | DOI Listing |
J Neurophysiol
September 2024
Department of Pharmacology, University of Michigan, Ann Arbor, Michigan, United States.
How cellular adaptations give rise to opioid analgesic tolerance to opioids like morphine is not well understood. For one, pain is a complex phenomenon comprising both sensory and affective components, largely mediated through separate circuits. Glutamatergic projections from the medial thalamus (MThal) to the anterior cingulate cortex (ACC) are implicated in processing of affective pain, a relatively understudied component of the pain experience.
View Article and Find Full Text PDFFront Pharmacol
May 2024
Department of Anesthesiology and Perioperative Medicine, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China.
Background: As a class of analgesics, opioids are frequently used to treat both acute and chronic moderate to severe pain. Patients frequently receive opioid painkillers after orthopedic accidents or surgeries. Evidence suggests that opioid drug users have a 55.
View Article and Find Full Text PDFBr J Pharmacol
June 2023
Department of Surgery, Miller School of Medicine, University of Miami, Miami, Florida, USA.
Background And Purpose: Opioids are the standard drug for pain management; however, their effects on gastric dysfunction are relatively understudied. Opioid users have a higher incidence of gastric pathology leading to increased hospitalization. Herein, we investigated the consequences of morphine use on gastric pathology and the underlying mechanisms.
View Article and Find Full Text PDFFront Immunol
August 2022
Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China.
Toll-like receptor 4 (TLR4) is a pattern-recognition receptor (PRR) that regulates the activation of immune cells, which is a target for treating inflammation. In this study, Cannabidivarin (CBDV), an active component of Cannabis, was identified as an antagonist of TLR4. , intrinsic protein fluorescence titrations revealed that CBDV directly bound to TLR4 co-receptor myeloid differentiation protein 2 (MD2).
View Article and Find Full Text PDFAm J Pathol
August 2022
Department of Surgery, Miller School of Medicine, University of Miami, Miami, Florida; Sylvester Comprehensive Cancer Center, Miami, Florida. Electronic address:
Opioids are the gold standard for chronic and acute pain management; however, their consequence on gastric function is relatively understudied. Opioid users have a higher incidence of gastric dysfunction, worse quality of life, increased hospitalizations, and increased use of antiemetic and pain modulator medications. The current study shows that morphine treatment in the murine model results in greater disruption of gastric epithelial cell morphology, increased gastric cell apoptosis, elevated inflammatory cytokines, and matrix metallopeptidase-9 secretion.
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