Development of Bombesin-Like and Histamine-Like Innervation in the Bullfrog (Rana catesbeiana) Central Nervous System
Notice bibliographique
Résumé
Amphibians rely exclusively on behavioral thermoregulation to maintain body temperature within species- and developmental stage-specific critical limits. Several members of the bombesin family of peptides and histamine are included in a class of neurochemicals that have potent thermoregulatory effects in ectothermic and endothermic vertebrate species and may be involved in behavioral thermoregulation in amphibians. Because amphibians respond to environmental temperature cues differently in larval versus adult animals, we used immunocytochemistry to study developmental changes in bombesin-like (BN) and histamine-like (HA) innervation in the bullfrog brain and spinal cord. Neurons and fibers that were BN-immunoreactive and HA-immunoreactive were present in the earliest stage tadpoles examined (Gosner stage 29); BN-immunoreactive perikarya were found only in the preoptic area, posterior thalamic nucleus and in the rostroventral tegmentum of the mesencephalon. In the preoptic area, dramatic changes were observed in the number and staining intensity of BN-ir somata; neuronal labelling was greatest in tadpoles undergoing tail resorption (i.e. metamorphic climax) and was nearly absent in adults. Neurons immunoreactive to BN in the ventral mesencephalon also were developmental stage-dependent; limb-bud growth stage tadpoles had the largest numbers of labelled neurons, whereas in the adults, labelled cells were rarely visible in this area. The highest density of fibers was in the medial septum, lateral amygdala, and the optic tectum. Fewer fibers were observed within the dorsal and ventral hypothalamus, the pineal gland, and all the thalamic nuclei. Perikarya immunoreactive to HA were localized in the dorsal infundibular nucleus of the hypothalamus. Immunoreactivity was present in all developmental stages examined, and the numbers of labelled cells increased throughout metamorphosis to a maximum in adult brains. Fibers were found in the medial septum, medial amygdala, preoptic area, thalamus, pineal gland, hypothalamus and optic tectum. These results show that BN- and HA-immunoreactivities are established early in larval development, but their phenotypes are differentially expressed during larval and adult growth stages. This pattern suggests that reorganization of BN-like and HA-like neural circuitry may occur during metamorphosis and may be involved in the reported developmental changes in amphibian thermoregulation. In addition, BN-like peptides and HA may modulate other related mechanisms of amphibian thermoregulation and behaviour, such as thermal acclimation, circadian shifts in temperature selection and feeding. To what extent they are involved in amphibian thermoregulation remains to be investigated.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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 ».