Splenic neurohormonal modulation of mesenteric vascular tone
Bibliographic record
Abstract
In portal hypertension, development of a hyperdynamic circulation is preceded by transient mesenteric vasoconstriction. Portal hypertension increases splenic venous outflow pressure. We hypothesized that this causes direct reflex activation of mesenteric vasoconstrictor nerves and splenorenal reflex-mediated activation of the renin-angiotensin system. In anaesthetized male rats, we measured mesenteric efferent nerve activity and mesenteric vascular conductance (MVC) after selectively elevating splenic venous pressure. Partial splenic vein occlusion raised splenic venous pressure (from 4.8 ± 0.4 to 24.1 ± 0.3 mmHg; n = 18) and induced a significant increase in mesenteric efferent nerve activity (from 23.2 ± 3.3 to 31.6 ± 3.5 spikes s(-1); n = 11); this response was abolished by prior splenic denervation (from 32.4 ± 2.4 to 31.2 ± 1.6 spikes s(-1); n = 7). Mesenteric vascular conductance, the ratio of superior mesenteric artery blood flow to mean arterial pressure, fell upon splenic vein occlusion (ΔMVC = -0.0120 ± 0.0014 ml min(-1)mmHg(-1); P < 0.05, n = 10). This was attenuated by splenic denervation (ΔMVC = -0.0044 ± 0.0018 ml min(-1)mmHg(-1); P < 0.05, n = 8), but unaffected by mesenteric denervation (ΔMVC = -0.0145 ± 0.0020 ml min(-1)mmHg(-1); n = 6) or bilateral renal denervation (ΔMVC = -0.0106 ± 0.0021 ml min(-1)mmHg(-1); n = 5). Localized blockade of mesenteric vascular angiotensin II type 1 (AT(1)) receptors significantly attenuated the response (ΔMVC = -0.0058 ± 0.0017 ml min(-1)mmHg(-1); P < 0.05, n = 5), whereas blockade of both AT(1) and α(1)-adrenergic receptors caused a significant increase in mesenteric conductance (ΔMVC = +0.0033 ± 0.0010 ml min(-1)mmHg(-1); P < 0.05, n = 6). Our evidence suggests that increased splenic venous outflow pressure reflexly activates adrenergic/angiotensinergic mesenteric nerves, vasodilator mesenteric nerves and the renin-angiotensin system. We propose that obstruction to splenic venous outflow, such as would normally accompany portal hypertension, induces reflex mesenteric vasoconstriction independently of the increase in portal venous pressure.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.000 | 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 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".