Journal: Journal of Biomedical Science

Article Title: OPRM1/MRGPRX1 heterodimers drive opioid-induced itch through a peripheral mechanism

doi: 10.1186/s12929-026-01238-x

Figure Lengend Snippet: Endogenous µ-opioid agonists induce OPRM1/MRGPRX1-dependent calcium mobilization. A Schematic representation of a calcium imaging assay to verify whether endogenous opioids can induce intracellular calcium mobilization via OPRM1/MRGRPX1. B Time course of normalized fluorescence (F/F₀) in HEK293T cells co-expressing mouse Oprm1 and MrgprX1 (mOprm1/mMrgprX1) after treatment with 1 µM β-endorphin, in the absence or presence of 10 µM naltrexone. C Dose–response relationship showing ΔPeak F/F₀ in mOprm1/mMrgprX1 cells treated with increasing concentrations of β-endorphin (0.01–10 µM). Time-course calcium mobilization in mOprm1/mMrgprX1 cells treated with 1 µM endomorphin-1 ( D ) or endomorphin-2 ( E ), with or without naltrexone. F Calcium responses (F/F 0 ) in HEK293T cells co-expressing hOPRM1 and hMRGPRX1 (hOPRM1/hMRGPRX1) treated with 1 µM β-endorphin in the presence of naltrexone (10 µM) or berbamine (10 µM, an MRGPRX1 antagonist). G Quantification of peak responses (ΔPeak F/F 0 ) in hOPRM1/hMRGPRX1 cells treated with endomorphin-1 or endomorphin-2, with or without berbamine. ***p < 0.001 compared to control

Article Snippet: The levels of β-endorphin were measured using a mouse β-endorphin ELISA kit (catalog # CSB-E06827m; CUSABIO, Houston, USA), following the manufacturer’s protocols.

Techniques: Imaging, Fluorescence, Expressing, Control

Journal: Journal of Biomedical Science

Article Title: OPRM1/MRGPRX1 heterodimers drive opioid-induced itch through a peripheral mechanism

doi: 10.1186/s12929-026-01238-x

Figure Lengend Snippet: Peripheral OPRM1 mediates opioid-induced and atopic dermatitis–associated itch. A Schematic of intradermal DAMGO injection and subsequent scratching behavior assay. B Quantification of scratching bouts over 60 min in wild-type mice following intradermal injection of vehicle (Control, n = 6) or DAMGO (n = 7). C Schematic of investigation into the effect of MC903 treatment on OPRM1/MRGPRX1 heterodimers in sensory neurons. D Spontaneous scratching bouts measured over 30 min in control (n = 6) and MC903-treated mice (n = 8). E Time-course calcium mobilization (F/F₀) in dorsal root ganglion (DRG) neurons from wild-type (WT) and MC903-treated mice stimulated with 10 µM DAMGO. F Quantification of peak calcium responses (ΔPeak F/F₀) in DRG neurons from control and MC903-treated mice stimulated with DAMGO. Numbers shown inside the bars indicate the sample sizes (n). G DAMGO-evoked calcium signals in MC903 DRG neurons (n = 787) were significantly diminished by MrgprX1 siRNA (n = 580). KCl (100 mM) was applied to confirm neuronal viability. H Immunofluorescence micrographs of lumbar DRG sections from control (identical to Fig. A) and MC903-treated mice. OPRM1 (green), MRGPRX1 (red), and nuclei (DAPI, blue) merge to reveal colocalization. Scale bar = 50 µm. I – L Quantification of gene expression changes (fold change) in DRG neurons from MC903-treated mice for Oprm1 ( I ), Mrgprx1 ( J ), Trpv1 ( K ), and Trpa1 ( L ). M Schematic of assay to verify changes of β-endorphin levels in MC903-treated mice. Levels of β-endorphin in the skin ( N ) and serum ( O ) of control and MC903-treated mice. *p < 0.05, ***p < 0.001, ns = not significant

Article Snippet: The levels of β-endorphin were measured using a mouse β-endorphin ELISA kit (catalog # CSB-E06827m; CUSABIO, Houston, USA), following the manufacturer’s protocols.

Techniques: Injection, Behavioral Assay, Control, Immunofluorescence, Gene Expression

Journal: bioRxiv

Article Title: The Endocannabinoid System’s Contribution to Placebo Analgesia

doi: 10.64898/2026.02.25.707676

Figure Lengend Snippet: To investigate the contribution of eCB and β-endorphin, and their interaction to placebo analgesia, we used a validated placebo paradigm. (A) First, to determine individual stimulus intensities and stimulation sites, we applied an adaptive staircase calibration procedure for thermal heat pain. At the beginning of the placebo paradigm, participants were informed that they would be receiving two creams during the procedure: a highly potent experimental analgesic cream, and a control cream. In reality, both creams provided were Vaseline (petroleum jelly, Vaseline Healing Jelly Original, Unilever). Red lines and drops indicate blood sampling. Next, participants underwent three blocks of testing (B): a manipulation block followed by two test blocks (conditions: placebo, control), counterbalanced across participants. Blood was drawn before and after each block. In the manipulation block, participants received individually calibrated heat stimuli to elicit a rating of 8/10 to control cream sites, and 4/10 to placebo cream sites. This manipulation served to condition participants and bolster expectations. For the next two blocks, participants received heat stimuli calibrated to elicit a 6/10, either on the control cream sites, or on the ‘analgesic’ cream sites, depending on the block (placebo, control). (C) Each block of stimulation consisted of twelve trials. At the end of each trial, participants provided a pain intensity rating. Panel B was made using Biorender.

Article Snippet: Serum concentrations of β-endorphin were analysed by competitive enzyme immunoassay using a human β-endorphin ELISA Kit (HUFI00498, Assay Genie, Dublin, Ireland), as per manufacturer instructions.

Techniques: Cream, Control, Sampling, Blocking Assay

Journal: bioRxiv

Article Title: The Endocannabinoid System’s Contribution to Placebo Analgesia

doi: 10.64898/2026.02.25.707676

Figure Lengend Snippet: (A) Ratings plotted at low circulating β-endorphin levels (-1 SD). Participants with higher FAAH analyte values (+1 SD) reported increased placebo analgesia, reflected in lower pain ratings in the placebo condition relative to control. ( B) Ratings plotted at mean circulating β-endorphin levels. Higher FAAH analyte values (+1 SD) were associated with reduced pain ratings under placebo compared to control. (C) Ratings plotted at high circulating β-endorphin levels (+1 SD). Minimal relationship between FAAH analyte values and placebo analgesia. Error bars represent ±1 SE.

Article Snippet: Serum concentrations of β-endorphin were analysed by competitive enzyme immunoassay using a human β-endorphin ELISA Kit (HUFI00498, Assay Genie, Dublin, Ireland), as per manufacturer instructions.

Techniques: Control

Journal: Scientific Reports

Article Title: Metapanax delavayi extract as a neurocutaneous modulator via CRHR1/POMC/MC1R signaling

doi: 10.1038/s41598-026-39343-4

Figure Lengend Snippet: MDE attenuated capsaicin-induced elevations in emotion-associated gene expression and hormonal levels. ( A - B ) Relative mRNA expression of cortisol-related genes ( 11β-HSD1 and 11β-HSD2 ) in SH-SY5Y cells treated with MDE ( N = 4). ( C - D ) Cortisol and β-endorphin contents in the cell culture medium of each group ( N = 5). Data are presented as mean ± SEM. p value using the one-way ANOVA. * p ≤ 0.05, ** p ≤ 0.01 versus control; # p ≤ 0.05, ## p ≤ 0.01 versus capsaicin-induced.

Article Snippet: The expression of cortisol (Catalogue Numbers: CEA806Mu) (Cloud-Clone Corp, China), β-endorphin (Catalogue Numbers: CSB-E06821h), IL-6 (Catalogue Numbers: CSB-E04638h), IL-8 (Catalogue Numbers: CSB-E04641h), and IL-1α (Catalogue Numbers: CSB-E04620h) (all from Cusabio, China) were also quantified using ELISA kits according to the manufacturer’s instructions.

Techniques: Gene Expression, Expressing, Cell Culture, Control

Journal: bioRxiv

Article Title: Hippocampal CA3 Nex/Neurod6 + neuron-specific TNFR2 alleviates chronic neuropathic pain by sex-dependently engaging opioid and endocannabinoid pathways

doi: 10.1101/2025.11.24.690195

Figure Lengend Snippet: Elevation in protein expression levels of POMC and β-endorphin in the CA3 region of the hippocampus in TNFR2 F/F (WT) mice treated with TNFR2 Agonist compared to that of the neuronal KO, Nex-Cre:TNFR2 F/F mice. (A) and (B) POMC expression levels in the hippocampal CA3 region of male and female, represented by immunohistochemistry (n=4 each group/sex). (C) and (D) β-Endorphin expression in the hippocampal CA3 region of male and female, represented by immunohistochemistry (n=4 each group/sex). Data are represented as mean ± SEM; *P < 0.05, **P < 0.01.

Article Snippet: Primary antibodies were applied overnight at 4 °C in blocking buffer: POMC (goat, 1:200; Novus) and β-endorphin (rat, 1:200; Phoenix Pharmaceuticals).

Techniques: Expressing, Immunohistochemistry