Nitric oxide regulates swimming in the jellyfish <i>Aglantha digitale</i>
Bibliographic record
Abstract
The cnidarian nervous system is considered by many to represent neuronal organization in its earliest and simplest form. Here we demonstrate, for the first time in the Cnidaria, the neuronal localization of nitric oxide synthase (NOS) in the hydromedusa Aglantha digitale (Trachylina). Expression of specific, fixative-resistant NADPH-diaphorase (NADPH-d) activity, characteristic of NOS, was observed in neurites running in the outer nerve ring at the base of the animal and in putative sensory cells in the ectoderm covering its tentacles. At both sites, diphenyleneiodonium (10(-4) M) abolished staining. Capillary electrophoresis confirmed that the NO breakdown products NO2- and NO3- were present at high levels in the tentacles, but were not detectable in NADPH-d-negative areas. The NADPH-d-reactive neurons in the tentacles send processes to regions adjacent to the inner nerve ring where swimming pacemaker cells are located. Free-moving animals and semi-intact preparations were used to test whether NO is involved in regulating the swimming program. NO (30-50 nM) and its precursor L-arginine (1 mM) stimulated swimming, and the effect was mimicked by 8-Br-cGMP (50-100 microM). The NO scavenger PTIO (10-100 microM) and a competitive inhibitor of NOS, L-nitroarginine methyl ester (L-NAME, 200 microM), significantly decreased the swimming frequency in free-moving animals, while its less-active stereoisomer D-nitroarginine methyl ester (D-NAME, 200 microM) had no such effect. 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ, 5-20 microM), a selective inhibitor of soluble guanylyl cyclase, suppressed spontaneous swimming and prevented NO-induced activation of the swimming program. We suggest that an NO/cGMP signaling pathway modulates the rhythmic swimming associated with feeding in Aglantha, possibly by means of putative nitrergic sensory neurons in its tentacles.
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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 | 0.001 | 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".