Acute Temperature Change Modulates the Response of I<sub>Ca</sub>to Adrenergic Stimulation in Fish Cardiomyocytes
Bibliographic record
Abstract
The purpose of this study was to investigate how the endogenous catecholamine adrenaline protects sarcolemmal Ca(2+) flux through the L-type Ca(2+) channel (I(Ca)) during acute exposure to cold in the fish heart. We examined the response of I(Ca) to adrenergic stimulation at three temperatures (7 degrees, 14 degrees, and 21 degrees C) in atrial myocytes isolated from rainbow trout acclimated to 14 degrees C. We found that I(Ca) amplitude varied directly with test temperature and was increased by adrenergic stimulation (AD; 5 nM and 1 microM) at all temperatures. However, I(Ca) was significantly more sensitive to adrenergic stimulation at the coldest test temperature. In fact, at 7 degrees C in the absence of AD, I(Ca) was extremely low. The addition of 1 microM AD increased peak I(Ca) 7.2-fold at 7 degrees C, 2.6-fold at 14 degrees C, and 1.6-fold at 21 degrees C and ameliorated the temperature-dependent difference in Ca(2+) influx across the cell membrane. We suggest that this increased adrenergic sensitivity is a critical compensatory mechanism that allows the rainbow trout heart to maintain contractility during acute exposure to cold temperatures. In particular, the tonic level of adrenergic stimulation provided by circulating plasma catecholamines (i.e., in the nM concentration range) may be crucial for effective excitation-contraction coupling in the cold cardiomyocyte.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".