Effects of cannabinoid receptor‐2 activation on accelerated gastrointestinal transit in lipopolysaccharide‐treated rats
Bibliographic record
Abstract
The biological effects of cannabinoids (CB) are mediated by CB(1) and CB(2) receptors. The role of CB(2) receptors in the gastrointestinal tract is uncertain. In this study, we examined whether CB(2) receptor activation is involved in the regulation of gastrointestinal transit in rats. Basal and lipopolysaccharide (LPS)-stimulated gastrointestinal transit was measured after instillation of an Evans blue-gum Arabic suspension into the stomach, in the presence of specific CB(1) and CB(2) agonists and antagonists, or after treatment with inhibitors of mediators implicated in the transit process. In control rats a CB(1) (ACEA; 1 mg kg(-1)), but not a CB(2) (JWH-133; 1 mg kg(-1)), receptor agonist inhibited basal gastrointestinal transit. The effects of the CB(1) agonist were reversed by the CB(1) antagonist AM-251, which alone increased basal transit. LPS treatment increased gastrointestinal transit. This increased transit was reduced to control values by the CB(2), but not the CB(1), agonist. This inhibition by the CB(2) agonist was dose dependent and prevented by a selective CB(2) antagonist (AM-630; 1 mg kg(-1)). By evaluating the inhibition of LPS-enhanced gastrointestinal transit by different antagonists, the effects of the CB(2) agonist (JWH-133; 1 mg kg(-1)) were found to act via cyclooxygenase, and to act independently of inducible nitric oxide synthase (NOS) and platelet-activating factor. Interleukin-1 beta and constitutive NOS isoforms may be involved in the accelerated LPS transit. The activation of CB(2) receptors in response to LPS is a mechanism for the re-establishment of normal gastrointestinal transit after an inflammatory stimulus.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".