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Beta2- and beta3-adrenoceptors activate glucose uptake in chick astrocytes by distinct mechanisms: a mechanism for memory enhancement?
- Source :
-
Journal of neurochemistry [J Neurochem] 2007 Nov; Vol. 103 (3), pp. 997-1008. Date of Electronic Publication: 2007 Aug 06. - Publication Year :
- 2007
-
Abstract
- Isoprenaline, acting at beta-adrenoceptors (ARs), enhances memory formation in single trial discriminated avoidance learning in day-old chicks by mechanisms involving alterations in glucose and glycogen metabolism. Earlier studies of memory consolidation in chicks indicated that beta3-ARs enhanced memory by increasing glucose uptake, whereas beta2-ARs enhance memory by increasing glycogenolysis. This study examines the ability of beta-ARs to increase glucose uptake in chick forebrain astrocytes. The beta-AR agonist isoprenaline increased glucose uptake in a concentration-dependent manner, as did insulin. Glucose uptake was increased by the beta2-AR agonist zinterol and the beta3-AR agonist CL316243, but not by the beta1-AR agonist RO363. In chick astrocytes, reverse transcription-polymerase chain reaction studies showed that beta1-, beta2-, and beta3-AR mRNA were present, whereas radioligand-binding studies showed the presence of only beta2- and beta3-ARs. beta-AR or insulin-mediated glucose uptake was inhibited by phosphatidylinositol-3 kinase and protein kinase C inhibitors, suggesting a possible interaction between the beta-AR and insulin pathways. However beta2- and beta3-ARs increase glucose uptake by two different mechanisms: beta2-ARs via a Gs-cAMP-protein kinase A-dependent pathway, while beta3-ARs via interactions with Gi. These results indicate that activation of beta2- and beta3-ARs causes glucose uptake in chick astrocytes by distinct mechanisms, which may be relevant for memory enhancement.
- Subjects :
- Adrenergic beta-2 Receptor Agonists
Adrenergic beta-3 Receptor Agonists
Adrenergic beta-Agonists pharmacology
Animals
Astrocytes drug effects
Brain cytology
Cells, Cultured
Chick Embryo
Dioxoles pharmacology
Dose-Response Relationship, Drug
Enzyme Inhibitors pharmacology
Ethanolamines pharmacology
GTP-Binding Protein alpha Subunits, Gi-Go drug effects
GTP-Binding Protein alpha Subunits, Gi-Go metabolism
GTP-Binding Protein alpha Subunits, Gs drug effects
GTP-Binding Protein alpha Subunits, Gs metabolism
Glucose pharmacokinetics
Insulin metabolism
Insulin pharmacology
Isoproterenol pharmacology
Memory drug effects
Phosphatidylinositol 3-Kinases metabolism
Phosphoinositide-3 Kinase Inhibitors
Protein Kinase C antagonists & inhibitors
Protein Kinase C metabolism
RNA, Messenger drug effects
RNA, Messenger metabolism
Receptors, Adrenergic, beta-2 genetics
Receptors, Adrenergic, beta-3 genetics
Signal Transduction drug effects
Signal Transduction physiology
Astrocytes metabolism
Brain metabolism
Glucose metabolism
Memory physiology
Receptors, Adrenergic, beta-2 metabolism
Receptors, Adrenergic, beta-3 metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0022-3042
- Volume :
- 103
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Journal of neurochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 17680985
- Full Text :
- https://doi.org/10.1111/j.1471-4159.2007.04789.x