Somatostatin Modulates Voltage-Gated K<sup>+</sup>and Ca<sup>2+</sup>Currents in Rod and Cone Photoreceptors of the Salamander Retina
Bibliographic record
Abstract
We investigated the cellular localization in the salamander retina of one of the somatostatin [or somatotropin release-inhibiting factor (SRIF)] receptors, sst(2A), and studied the modulatory action of SRIF on voltage-gated K(+) and Ca(2+) currents in rod and cone photoreceptors. SRIF immunostaining was observed in widely spaced amacrine cells, whose perikarya are at the border of the inner nuclear layer and inner plexiform layer. sst(2A) immunostaining was seen in the inner segments and terminals of rod and cone photoreceptors. Additional sst(2A) immunoreactivity was expressed by presumed bipolar and amacrine cells. SRIF, at concentrations of 100-500 nM, enhanced a delayed outwardly rectifying K(+) current (I(K)) in both rod and cone photoreceptors. SRIF action was blocked in cells pretreated with pertussis toxin (PTX) and was substantially reduced by intracellular GDP(beta)S. Voltage-gated L-type Ca(2+) currents in rods and cones were differently modulated by SRIF. SRIF reduced Ca(2+) current in rods by 33% but increased it in cones by 40%, on average. Both effects were mediated via G-protein activation and blocked by PTX. Ca(2+)-imaging experiments supported these results by showing that 500 nM SRIF reduced a K(+)-induced increase in intracellular Ca(2+) in rod photoreceptor terminals but increased it in those of cones. Our results suggest that SRIF may play a role in the regulation of glutamate transmitter release from photoreceptors via modulation of voltage-gated K(+) and Ca(2+) currents.
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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".