Leptin Stabilizes Breathing but does not affect CO <sub>2</sub> Chemosensitivity in Newborn Rat Pups
Bibliographic record
Abstract
Premature infants have periodic breathing (PB) and chronic intermittent hypoxia (CIH) that increases during the 2 nd week of life. Leptin (LEP) is a hormone produced by adipocytes and increases central CO 2 chemoreceptors sensitivity. LEP is also produced by the placenta, and in newborn infants LEP levels are highest at birth and then rapidly fall. We hypothesis that the fall in LEP after birth is associated with the increase frequency of PB and apnea leading to CIH during the 2 nd week of life in premature infants. Objective To determine the effect of exogenous LEP on breathing stability and CO 2 sensitivity during the first week of postnatal life, using whole body flow‐through plethysmograph in freely behaving newborn rats. Methods Sprague Dawley (SD) rat pups remained with the nursing dam until the time of the experiment. On postnatal day (PD) 7, rat pups were injected intraperitoneally with either vehicle (saline/n=5), LEP6 (6 μg/gr/n=4) and LEP9 (9 μg/gr/n=5). After injection the pup was returned to nursing dam and litter mates for 30 mins followed by 30 mins in the plethysmograph prior to recording. Respiratory tracings were captured using PowerLab 8 data acquisition system (ADInstruments) and analyzed using LabChart. Ventilatory parameters; frequency, V T and V e were compared during 21% O 2 , 40% O 2 /0% CO 2 , 40%O 2 /5%CO 2 and return to 40%O 2 /0%CO 2, and the coefficient of variation (CV) for V e was calculated for each condition in the 3 treatment groups (SAL, LEP6, LEP9). Results Similar to Stunden et al. in rat pups at PD 7–8 ( Stunden et al,, Respir Physiol, 2001 ), frequency, V T and V e did not significantly changed in response to hypercapnia (P=0.511), and LEP6 or LEP9 did not alter this response. However, LEP exposure did stabilize breathing with a reduction in the CV during 21%O 2 , 40%O 2 /0%CO 2 and 40%O 2 /5%CO 2 (Figure 1). Conclusion Our preliminary findings are consistent with that of Stunden et al, who reported no change in V e in response to hypercapnia at PD 6–8 in SD rats. At this age, the hypothalamus is insensitive to the effect of leptin on feeding and metabolism ( MacKay H et al., Mol Metab. 2014 ). Here we show that leptin does not induce nor augment CO2 chemosensitivity in newborn rats at PD7, but does at PD 18 (Gauda et al, unpublished data), and adults ( Isono S et al., Anesthesiology, 2009 ). However our data does show that leptin stabilizes breathing during the first week of life in newborn rat pups. We speculate that unstable breathing that occurs in premature infants may be associated with the precipitous fall in leptin levels after birth. 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".