Ewan St. John Smith
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psalmotoxin.bsky.social
Ewan St. John Smith
@psalmotoxin.bsky.social
1.9K followers 1K following 1.1K posts
👨🏻‍🔬& 👨🏻‍🏫🏳️‍🌈Neuroscientist in Cambridge UK interested in the neurobiology of pain and everything to do with naked mole-rats. 🏃🏻‍♂️, 📖 & 🤘
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psalmotoxin.bsky.social
Ah, that’s frustrating, I saw that it clashed with a few pain poster sessions!
November 15, 2025 at 3:59 PM
psalmotoxin.bsky.social
Was fun entertaining you all!
November 15, 2025 at 1:18 AM
psalmotoxin.bsky.social
Congratulations Paula 👏
November 14, 2025 at 11:44 AM
psalmotoxin.bsky.social
🤣
November 12, 2025 at 2:34 PM
Reposted by Ewan St. John Smith
artologica.net
Here's the lineup of #sfn25 artist exhibitors all on one page
SfN 2025 Art of Neuroscience
Full list of Exhibitors
open.substack.com
November 10, 2025 at 10:25 PM
psalmotoxin.bsky.social
Thanks for your kind words!
November 8, 2025 at 12:09 PM
Reposted by Ewan St. John Smith
psalmotoxin.bsky.social
To the colon! Acidic buffer virtually FAILED to activate lumbar splanchnic nerves from KO 🐭. a couple of years on from when @LukePaine4 first showed me the data I am still 🤯
(A) Representative rate histograms and (B) mean response profiles of GPR68+/+ (grey) and GPR68-/- (orange) colonic afferent activity in response to bath application of pH 6.5-4.0; shaded area is SEM (GPR68+/+ vs GPR68-/- main effect: P = <0.0001; two-way ANOVA; F(1,87) = 26.47). (C) Peak afferent activity at each pH (GPR68+/+ vs GPR68-/- unpaired t-test (or non-parametric equivalent); pH 6.5, P = 0.9126, t, df = 0.1115, 16; pH 6.0, P = 0.0074 (U = 18); pH 5.5, P = 0.003 (U = 10); pH 5.0, P = 0.0106 (U = 12); pH 4.0, P = 0.0008 (U = 10); N = 9-11 animals). (D) Area under the curve (AUC) for afferent responses across the pH range (GPR68+/+ vs GPR68-/- unpaired t-test (or non-parametric equivalent); pH 6.5, P = 0.2430, t, df = 1.212, 16; pH 6.0, P = 0.1145 (U = 32); pH 5.5, P = 0.003 (U = 10); pH 5.0, P = 0.0106 (U = 12); pH 4.0, P = 0.0015 (U = 12); N = 9-11 animals). U refers to the Mann-Whitney U statistic.
November 4, 2025 at 4:49 PM
psalmotoxin.bsky.social
Thus: Genetic/pharmacological modulation demonstrates GPR68’s role in acid-induced colonic nociception, supporting its therapeutic potential for pain management in colitis.
Thus: Genetic/pharmacological modulation demonstrates GPR68’s role in acid-induced colonic nociception, supporting its therapeutic potential for pain management in colitis.
November 4, 2025 at 4:49 PM
psalmotoxin.bsky.social
Lastly, we found that ogerin potentiated mechanical distension responses of the lumbar splanchnic nerve under acid, but not neutral conditions
(A) Schematic of experimental paradigm assessing the effects of the GPR68 PAM, Ogerin, (applied intraluminally) on colonic afferent responses to ramp distension. (B) Representative rate histograms and corresponding pressure traces from recordings showing afferent responses to ramp distensions 3-5 in pH 7.4, 6.8 and pH 6.8 + Ogerin (100 µM) groups. The dotted line highlights the sensitisation of afferent responses to distension in the pH 6.8 + Ogerin group. (C) Afferent response profiles of ramp distension 5 (0-80 mmHg) in pH 7.4 and pH 6.8 groups with and without Ogerin, normalised (norm.) to ramp distension 3 (*P < 0.05; two-way repeated measures ANOVA (main effect: P = 0.0493; F(3, 21) = 3.087) with Dunnett’s multiple comparisons test). Shaded area is SEM.
November 4, 2025 at 4:49 PM
psalmotoxin.bsky.social
Conversely, the positive allosteric modulate ogerin, but not ogerin negative control, ⇧ acid-induce lumbar splanchnic nerve firing in wildtype 🐭, but not in KO 🐭
The GPR68 PAM Ogerin potentiates colonic afferent responses to acid. (A) Schematic of the experimental paradigm assessing colonic afferent responses to bath application of pH 6.0 following treatment with the GPR68 positive allosteric modulator (PAM), Ogerin, or its inactive analogue ONC (Ogerin negative control). (B) Representative rate histograms of repeated afferent stimulation with pH 6.0. The 2nd response consisted of pretreatment with either Ogerin (top) or ONC (bottom). (C) Peak change in afferent activity of response 2 (post-drug application) normalised to response 1 (pre-drug application) for vehicle, ONC or Ogerin (in GPR68+/+ and GPR68-/- mice) treated groups (Ogerin vs ONC, P = 0.0005; Ogerin vs Vehicle, P = 0.0019; Ogerin vs GPR68-/-, P = 0.0002; one-way ANOVA (main effect: P = 0.0002; F(3, 18) = 11.36); with Dunnett’s multiple comparisons test; N = 5-6 animals per group). (D) AUC of response 2 (post-drug application) normalised to response 1 (pre-drug application) for vehicle, ONC or Ogerin (in GPR68+/+ and GPR68-/- mice) treated groups (Ogerin vs ONC, P = 0.0047; Ogerin vs Vehicle, P = 0.0014; Ogerin vs GPR68-/-, P = 0.0237; one-way ANOVA (main effect: P = 0.002; F(3, 18) = 7.367); with Dunnett’s multiple comparisons test; N = 5-6 animals per group).
November 4, 2025 at 4:49 PM