Domoic acid-induced neurodegeneration resulting in memory loss is mediated by Ca2+ overload and inhibition of Ca2+ + calmodulin-stimulated adenylate cyclase in rat brain (review).
Notice bibliographique
Résumé
Domoic acid is a shellfish toxin which produces neurodegeneration and CNS dysfunction, notably a loss of short-term memory. This toxin was found in blue mussels (Mytilus edulis) cultivated in river water in the east coast of Prince Edward Island in Canada and caused human poisoning. The toxin was localized in the stomach of blue mussels, which was engorged with algae, Nitzschia pungens, that were filtered from the surrounding water. The toxin was isolated from contaminated mussels or phytoplankton, and identified chemically as domoic acid (DOM) which is a tricarboxylic amino acid. Due to its structural resemblance to glutamic, aspartic and kainic acids, DOM was considered to produce excitotoxicity by similar mechanism(s). However, the latest evidence indicates differences in its mode of action from these excitatory agonists. We propose that DOM induces toxicity via changes in intracellular concentration of Ca2+ ([Ca2+]i). Results of our studies demonstrate that DOM elevated [Ca2+]i in brain slices. Glucose deprivation and removal of Na+ from the Krebs-bicarbonate medium further elevated [Ca2+]i, suggesting a relationship between glucose metabolism (cell energy), Na+ and Ca2+ transfer across neuronal membrane. DOM-induced rise in [Ca2+]i was due to enhanced Ca2+ influx and its mobilization from the endoplasmic reticulum. In addition, diminished Ca2+-ATPase activity due to lack of ATP, and variable amounts and expression of calcium binding proteins (CaBP) appear to contribute to an elevation in [Ca2+]i in response to DOM. Most interestingly, DOM inhibited Ca2+ and calmodulin-stimulated adenylate cyclase activity in brain membranes, resulting in reduced level of cyclic AMP. Cyclic AMP is known to activate protein kinase A to enhance phosphorylation of Ca2+ channels, thereby, reducing Ca2+ influx to prevent the development of Ca2+ overload which is detrimental to neuronal cell function (neuroprotection). However, DOM reduced cyclic AMP level, diminishing the feedback control of cyclic AMP on Ca2+ influx via Ca2+ channels, thereby, allowing continuing enhanced Ca2+ influx, resulting in Ca2+ overload which adversely affects many intracellular processes to induce toxicity. Ca2+ and CaM-stimulated adenylate cyclase activity in brain is highly correlated with the acquisition and retention of memory in different organisms. Calcium binding proteins bind Ca2+ reversibly and provide intracellular Ca2+ buffering, thereby, protecting neuronal cell from damage by Ca2+ overload in response to DOM. DOM appears to interfere with the cross talk between Ca2+ and cyclic AMP which is necessary for neuronal cell function. We have also demonstrated that DOM stimulates GLU release from synaptosomes and may produce some of its toxic effects via excess GLU in the neuronal synapse. In conclusion, DOM-induced neurodegeneration resulting in a loss of memory is mediated by Ca2+ overload, inhibition of Ca2+ and CaM-stimulated adenylate cyclase activity, and/or by the enhanced GLU release in rat brain.
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 distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,002 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| 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 | 0,001 |
| 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 tête enseignante, 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 ».