The<i>C. elegans</i>T-type calcium channel CCA-1 boosts neuromuscular transmission
Bibliographic record
Abstract
Low threshold-activated or T-type calcium channels are postulated to mediate a variety of bursting and rhythmic electrical firing events. However, T-type channels' exact physiological contributions have been difficult to assess because of their incompletely defined pharmacology and the difficulty in isolating T-type currents from more robust high threshold calcium currents. A current in C. elegans pharyngeal muscle displays the kinetic features of a T-type calcium channel and is absent in animals homozygous for mutations at the cca-1 locus (see accompanying paper). cca-1 is expressed in pharyngeal muscle and encodes a protein (CCA-1) with strong homology to the alpha1 subunits of vertebrate T-type channels. We show that CCA-1 plays a critical role at the pharyngeal neuromuscular junction, permitting the efficient initiation of action potentials in response to stimulation by the MC motor neuron. Loss of cca-1 function decreases the chance that excitatory input from MC will successfully trigger an action potential, and reduces the ability of an animal to take in food. Intracellular voltage recordings demonstrate that when wild-type cca-1 is absent, the depolarizing phase of the pharyngeal action potential tends to plateau or stall near -30 mV, the voltage at which the CCA-1 channel is likely to be activated. We conclude that the CCA-1 T-type calcium channel boosts the excitatory effect of synaptic input, allowing for reliable and rapid depolarization and contraction of the pharyngeal muscle. We also show that the pharyngeal muscle employs alternative strategies for initiating action potentials in certain cases of compromised MC motor neuron function.
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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) | 0.002 | 0.001 |
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".