Characterization of appetite-‐regulating factors in platyfish, Xiphophorus maculatus (Cyprinodontiformes Poeciliidae) and cunner, Tautogolabrus adspersus
Notice bibliographique
Résumé
The regulation of energy in fish, like most vertebrates, is a complex process that involves a number of chemical signals originating and networking in different parts of the brain and throughout the body. These signals include anorexigenic hormones that suppress feeding and hunger [e.g. cholecystokinin (CCK) and cocaine-‐and amphetamine-‐regulated transcript (CART)] as well as orexigenic peptides that stimulate feeding behaviour and food intake [e.g. orexin and neuropeptide Y (NPY)]. Platyfish, Xiphophorus maculatus, are freshwater viviparous fish found in tropical waters from South America to northern Mexico. Although these fish have been the object of numerous physiology and behavioural studies, very little is known about the endocrine mechanisms regulating their feeding. In order to elucidate the role of these peptides in the regulation of feeding, we examined the effects of peripheral injections of CCK and orexin on feeding behaviour and food intake. Injections of CCK decreased both food intake and searching behaviour, while injections of orexin increased searching behaviour but did not seem to have an effect on food consumption. In order to better characterize these peptides, we performed tissue distribution and gene expression studies. Tissue distribution studies show that CCK, CART, NPY and orexin all show a widespread distribution in brain and several peripheral tissues, including intestine. In addition, we compared the expression of these peptides in brain and gut between fed and 10-‐day fasted platyfish using qPCR. Fasting caused decreases in both CCK and CART mRNA expressions in the brain and a decrease in CCK expression in the intestine. There was also a significant increase in orexin mRNA expression in the brain as a result of fasting. Cunners, Tautogolabrus adspersus, are cold-‐water oviparous (egg laying) marine fish that can be found from Northern Newfoundland to all along the coast of the western North Atlantic. In cunner, fasting for 10 days caused a decrease in CCK in the brain, and a significant increase in orexin expression in the brain. Fasting had no significant effect on either NPY or CART expression. Furthermore, fasting had no effect on the expression of the peptides studies in the intestine. We also compared the expression of these peptides as a result of fasting in males and females of both species. In platyfish, there was no significant gender specific differences found in the expression of the peptides. In cunner, females showed a significantly higher NPY expression in the brain than males, although this was unique to NPY. The widespread distribution and the fasting-‐induced changes in expression of these peptides suggest that they might have several physiological roles in platyfish, including the regulation of feeding.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».