Temperature-related differences in the calcium transient between Atlantic cod (Gadus morhua) and steelhead trout (Oncorhynchus mykiss) cardiomyocytes
Bibliographic record
Abstract
The Atlantic cod, Gadus morhua, differs from many teleosts in that its heart does not respond to adrenergic stimulation, and is more capable of maintaining function during acute temperature changes. To examine if differences in intracellular calcium mobilization are associated with these atypical responses, confocal microscopy was used to study the calcium handling of cardiac cells from Atlantic cod vs. steelhead trout at their acclimation temperature (10ºC), or subjected to acute temperature changes (to 4 and 16ºC), while being stimulated across a range of frequencies (10 – 110 min⁻¹). In addition, cells were tested with and without tonic (10 nM) levels of adrenaline at 10ºC, and pharmacological blockers were used to study the relative contributions of the L-type Ca²⁺ channel, sarcoplasmic reticulum and Na+/Ca²⁺ exchanger to the Ca²⁺ transient. Consistent with previous in vitro and in situ studies, there were few significant effects of adrenaline on the Ca²⁺ transient of cod cardiomyocytes, yet adrenaline had significant positive inotropic effects on trout cardiomyocytes. At 10ºC, peak Ca²⁺ (F/F₀) only differed between the two species at low stimulation frequencies (10, 30 min-1), with trout F/F₀ 25-35% higher. In contrast, the time to peak Ca²⁺ and the time to half relaxation were both shorter (by 10 – 35% across frequencies) in cod. Acute temperature changes caused a shift in the Ca²⁺ - frequency relationship in both species, with F/F₀ values higher for trout at low frequencies (< 70 min⁻¹) at 4ºC, whereas this parameter was greater at all frequencies except 10 min⁻¹ in cod at 16ºC. Unfortunately, these experiments did not highlight clear species differences in the relative contributions of the L-type Ca²⁺ channels, sarcoplasmic reticulum and Na+/Ca²⁺ exchange to the Ca²⁺ transient.
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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 | 0.000 |
| 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 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".