Journal: bioRxiv

Article Title: Alcohol and Opioids Modulate Excitatory Inputs to the SCN

doi: 10.64898/2026.04.30.721903

Figure Lengend Snippet: A. Schematic depicting experimental design. SCN slices were prepared from 7-8-month-old MOR-Cre;Ai32 mice of both sexes. B. Light stimulation of MOR input has no significant effect on firing rate when all neurons were combined together (p < 0.05 by Friedman Repeated Measures Analysis of Variance on Ranks, n = 13/7). C. Pie chart showing differential responses of SCN neurons to light stimulation. Out of all neurons recorded, the majority showed an increase of greater than 10% during light stimulation (n = 13,7). D. Light stimulation induced a significant increase in firing in a subset of SCN neurons, n = 6/3. E. Sample traces of 3 sweeps in an SCN neuron showing repeated, reversible excitation when MOR input was optogenetically activated. F. A smaller subset of SCN neurons was reversibly inhibited by light stimulation, n = 3/3. G. Sample traces of 3 sweeps in an SCN neuron showing repeated, reversible inhibition when MOR input was optogenetically activated. H. Sample image of MOR+ fibers and neurons in the SCN and surrounding area. Image taken from an MOR-Cre;Ai14 mouse, inset scale bar: 10µm. I. Proposed neurocircuit of converging glutamatergic and GABAergic MOR+ input to the SCN.

Article Snippet: VGlut2-Cre, MOR-Cre, and Ai32 mice were obtained from the Jackson Laboratory.

Techniques: Inhibition

Journal: bioRxiv

Article Title: Alcohol and Opioids Modulate Excitatory Inputs to the SCN

doi: 10.64898/2026.04.30.721903

Figure Lengend Snippet: A. Schematic depicting experimental design. SCN slices were prepared from MOR-Cre;Ai32 mice of both sexes. B. Sample trace of an optically induced EPSC (oEPSC) in an SCN neuron, showing ∼5 ms latency. C. Bath application of AMPAR antagonist NBQX (20 µM) reduced oEPSC amplitude in an SCN neuron. D. Sample trace of a recorded neuron showing the baseline (BL), the response during NBQX application, and the subtraction of the baseline and NBQX response to equal the actual oEPSC response. E. The MOR agonist DAMGO reduced the amplitude of oEPSCs following MOR stimulation. F. Schematic depicting experimental design. SCN slices were prepared from VGlut2-Cre;Ai32 mice of both sexes. G. Time course showing bath application of fentanyl (1 µM) acutely and persistently suppresses glutamatergic input to SCN neurons. H. Fentanyl bath application significantly reduced the firing rate of oEPSCs compared to baseline (BL). This effect persisted throughout the washout (wash) period (***p < 0.001 by one-way RM ANOVA, n = 6/4).

Article Snippet: VGlut2-Cre, MOR-Cre, and Ai32 mice were obtained from the Jackson Laboratory.

Techniques:

Journal: Nature

Article Title: GTP release-selective agonists prolong opioid analgesic efficacy

doi: 10.1038/s41586-025-09880-5

Figure Lengend Snippet: a . Spinal cord from C57BL6/J male mice stimulated with 10 µM DAMGO induces a 40% increase in GTPγS binding over baseline (0) (left, p < 0.001, paired t-test, n = 3 mice as shown). Removing sodium from the system leads to an ~4-fold increase in baseline binding of 35 S-GTPγS (middle, **p < 0.01, paired t-test, n = 3 mice). Under these conditions, DAMGO-induced release cannot be detected (right, p > 0.05 paired t-test, n = 3 mice). b . In CHO cells expressing mouse MOR cells, the inclusion of 100 nM DAMGO in the preloading condition, in the presence of sodium, is sufficient to load the 35 S-GTPγS and that DAMGO-mediated release can still be observed; the purple line and diamonds plots the curve with the consideration of the residual 1 nM remaining DAMGO in the chase (*p < 0.05 unpaired t-test comparing individual pEC 50 ; pEC 50 presented with 95%CI in figure legend). c . Use of 100 nM DAMGO in the preloading of spinal cord membranes results in a 10.5% increase in labeling that does not occur in membranes from MOR-KO mice (*p < 0.05 paired t-test, n = 3 mice). d . Neither 35 S-GTPγS binding nor release is detected in spinal cord membranes from MOR-KO mice (plotted is the mean with s.e.m.; n = 3 mice per point). Accompanies Fig. .

Article Snippet: Male and female C57BL6/J (JAX:000664) and male MOR-KO (JAX:007559) mice were purchased from The Jackson Laboratory.

Techniques: Binding Assay, Expressing, Labeling

Journal: Nature

Article Title: GTP release-selective agonists prolong opioid analgesic efficacy

doi: 10.1038/s41586-025-09880-5

Figure Lengend Snippet: a – c , Morphine ( a ), Muzepan1 ( b ) and Muzepan2 ( c ) were tested at the indicated doses (in mg kg −1 , intraperitoneal injection (IP)) in the hot plate (left) and tail flick (middle) assays in wild-type and MOR-knockout (MOR-KO) mice. Right, potency was determined by comparing the response at 1 h based on the percentage of MPE calculated from the baseline (BL) and a cut-off time of 20 s for the hot plate and 30 s for the tail flick. Potency curves are extended to convey 0% (determined by baseline) and 100% (determined by maximum cut-off time used to estimate the ED 50 ); potencies are presented with 95% confidence interval in the legends. a , Morphine: n = 6 (3 mg kg −1 and 24 mg kg −1 ), n = 10 (6 mg kg −1 and 12 mg kg −1 ). b , Muzepan1: n = 8 (3 mg kg −1 ), n = 5 (6 mg kg −1 and 12 mg kg −1 ), n = 7 (24 mg kg −1 ); MOR-KO: n = 5. c , Muzepan2: n = 4 (6 mg kg −1 ), n = 10 (12 mg kg −1 ), n = 6 (24 mg kg −1 ); MOR-KO: n = 3. HP, hot plate assay; TF, tail flick assay.

Article Snippet: Male and female C57BL6/J (JAX:000664) and male MOR-KO (JAX:007559) mice were purchased from The Jackson Laboratory.

Techniques: Injection, Tail Flick Test, Knock-Out