H <sub>1</sub> /H <sub>2</sub> histamine receptor blockade lowers substrate‐dependent mitochondrial H <sub>2</sub> O <sub>2</sub> emission in deep gastrocnemius muscle following a bout of prolonged exercise
Bibliographic record
Abstract
Prolonged exercise increases oxidative metabolism in skeletal muscle mitochondria, which is facilitated, in part, by increased blood flow and delivery of nutrients and oxygen. Histamine mediates many acute exercise responses, including sustained vasodilation and associated delivery of substrates to muscle. We tested the hypothesis that H 1 and H 2 histamine receptor blockade would attenuate exercise‐induced changes in skeletal muscle mitochondrial function. Adult male Wistar rats (75–94 days old; 441.2 ± 39.5 g) were randomly assigned to one of three groups ( n = 12/group): exercise, in the form of one hour of continuous treadmill running at 20 cm/sec (Group 1); mass‐specific oral gavage with H 1 antagonist fexofenadine (7.11 mg/kg) and H 2 antagonist ranitidine (3.95 mg/kg) one hour prior to the same exercise protocol (Group 2); control, which received neither antihistamines nor exercise (Group 3). An hour post exercise, mitochondrial function was assessed in saponin‐permeabilized myofibers from deep gastrocnemius (mixed fiber types) and soleus (oxidative) skeletal muscle. A sequential substrate‐inhibitor titration protocol was used to examine multiple mitochondrial metabolic pathways (i.e., malate + octanoyl‐carnitine, ADP, lactate + NAD + , pyruvate, glutamate, succinate, inhibitors of antioxidant defense glutathione peroxidase and thioredoxin). Substrate‐dependent oxygen consumption ( J O 2 ; high‐resolution respirometry) was not different between treatments; however, H 1 and H 2 histamine receptor blockade significantly decreased hydrogen peroxide emission (mH 2 O 2 ; fluorometric monitoring of Amplex Red oxidation) in deep gastrocnemius fibres ( P < .05). Given the widespread and routine use of antihistamines, further research into the effects of these antagonists on mitochondrial function, in the context of exercise, is warranted. Support or Funding Information The Natural Sciences and Engineering Research Council of Canada (NSERC), The Nova Scotia Health Research Foundation (NSHRF), and Canada Foundation for Innovation (CFI) This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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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) | 0.000 | 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".