Opioid and tachykinin systems are involved in modulation of pain transmission in the spinal cord. Regulation of surface opioid receptors on nociceptive afferents is critical for opioid analgesia. Plasma-membrane insertion of delta-opioid receptors (DORs) is induced by stimulus-triggered exocytosis of DOR-containing large dense-core vesicles (LDCVs), but how DORs become sorted into the regulated secretory pathway is unknown. Here we report that direct interaction between protachykinin and DOR is responsible for sorting of DORs into LDCVs, allowing stimulus-induced surface insertion of DORs and DOR-mediated spinal analgesia. This interaction is mediated by the substance P domain of protachykinin and the third luminal domain of DOR. Furthermore, deletion of the preprotachykinin A gene reduced stimulus-induced surface insertion of DORs and abolished DOR-mediated spinal analgesia and morphine tolerance. Thus, protachykinin is essential for modulation of the sensitivity of nociceptive afferents to opioids, and the opioid and tachykinin systems are directly linked by protachykinin/DOR interaction.
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http://dx.doi.org/10.1016/j.cell.2005.06.010 | DOI Listing |
J Comput Chem
January 2025
Departamento de Fisicoquímica, Facultad de Química, Universidad Nacional Autónoma de México, Coyoacán, CDMX, Mexico.
The G protein-coupled receptor (GPCR) pharmacology accounts for a significant field in research, clinical studies, and therapeutics. Computer-aided drug discovery is an evolving suite of techniques and methodologies that facilitate accelerated progress in drug discovery and repositioning. However, the structure-activity relationships of molecules targeting GPCRs are highly challenging in many cases since slight structural modifications can lead to drastic changes in biological functionality.
View Article and Find Full Text PDFBr J Pharmacol
January 2025
Center for Clinical Pharmacology, Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA.
Background And Purpose: Pituitary adenylate cyclase activating polypeptide (PACAP) is a human migraine trigger that is being targeted for migraine. The δ-opioid receptor (δ-receptor) is a novel target for the treatment of migraine, but its mechanism remains unclear. The goals of this study were to develop a mouse PACAP-headache model using clinically significant doses of PACAP; determine the effects of δ-receptor activation in this model; and investigate the co-expression of δ-receptors, PACAP and PACAP-PAC1 receptor.
View Article and Find Full Text PDFToxicol Appl Pharmacol
January 2025
Department of Animal and Biomedical Sciences, School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, China; Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, China. Electronic address:
Opioids are potent analgesics in clinical pain management but exert variable analgesia in different pain types. Opioid-induced constipation is a common side effect of opioid therapy, and whether opioids induce different gastrointestinal motility inhibitions in different pain types is unknown. In this study, we evaluated the antinociceptive effects and inhibition of upper gastrointestinal transit and colonic bead expulsion of morphine, DAMGO, and Deltorphin in mouse CFA chronic inflammatory pain, SNI chronic neuropathic pain, and carrageenan chronic inflammatory pain models.
View Article and Find Full Text PDFNeuroscience
January 2025
Johns Hopkins University School of Medicine, Department of Neurology, and the Kennedy Krieger Institute, Baltimore, MD, United States.
Deer mice provide a valuable naturally occurring animal model for investigating pathophysiological mechanisms underlying repetitive behaviors. Prior investigations using this model have identified abnormalities in the cortico-basal ganglia circuitry, including alterations within the indirect pathway and levels of endogenous opioids in the frontal cortex. In this study, the behaviors of n = 7 mice were quantified, and their brains were sectioned.
View Article and Find Full Text PDFFront Mol Biosci
December 2024
Department of Biology, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates.
Hemorphins are short atypical opioid peptide fragments embedded in the β-chain of hemoglobin. They have received considerable attention recently due to their interaction with opioid receptors. The affinity of hemorphins to opioid receptors μ-opioid receptor (MOR), δ-opioid receptor (DOR), and κ-opioid receptor (KOR) has been well established.
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