Neurokinin Receptors in the Guinea Pig Ileum
Bibliographic record
Abstract
Experiments were performed in the longitudinal muscle strip of the guinea pig ileum to characterize the receptors involved in the contractile response of this preparation to neurokinins. Antagonists for the NK-1 (CP 96345, CP 99994) and NK-2 (SR 48968) receptors, atropine for NK-3 receptors, as well as diphenhydramine (histamine H1 receptor antagonist) and indometacin (cyclooxygenase inhibitor) were used to determine the relative contribution of neurokinin receptors and some endogenous agents to the myotropic effects of substance P (SP) and neurokinin receptor selective agonists. The present findings indicate that the three neurokinin receptor types take part in the contractile activities of SP-related peptides. NK-1 receptors, probably localized in the smooth muscle, are inhibited only by the two CP compounds and not by atropine or the other agents. NK-2 receptors contribute to the contraction by 5-10% and are blocked by SR 48968. NK-3 receptors act indirectly through the release of acetylcholine from the myenteric plexus, since activities of [MePhe7]NKB and senktide are blocked by atropine. Septide behaves as a selective NK-1 receptor agonist and does not show any difference with SP, except for higher sensitivity to CP antagonists. The same is observed with Ac[Arg6,Sar9,Met(O2)11]SP(6-11), another NK-1-selective fragment. Discrepancies between antagonist pA2 values obtained against undeca- and hexapeptide agonists are interpreted as due to a stronger binding affinity of undecapeptide agonists as compared with the hexapeptides. Results of binding assays confirm data from the literature by showing that undecapeptide agonists have higher affinities than hexapeptides, particularly septide,, and such discrepancies (with the biological assays) can also be explained by the reduction or absence of the cationic charge at the N terminal of septide.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 teacher head, 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".