Insulin-Like Growth Factor-I Promotes Neurogenesis and Synaptogenesis in the Hippocampal Dentate Gyrus during Postnatal Development
| Autor: | John R. O'Kusky, Ping Ye, A. Joseph D'Ercole |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Telencephalon
medicine.medical_specialty medicine.medical_treatment Synaptogenesis Hippocampus Cell Count Mice Transgenic Hippocampal formation Biology Mice Insulin-like growth factor Insulin-Like Growth Factor II Cerebellum Internal medicine medicine Animals Diencephalon Insulin-Like Growth Factor I ARTICLE Cerebral Cortex Neurons Analysis of Variance General Neuroscience Dentate gyrus Body Weight Neurogenesis Organ Size Granule cell medicine.anatomical_structure Endocrinology Dentate Gyrus Synapses Neuron Neuroscience |
| Zdroj: | The Journal of Neuroscience. 20:8435-8442 |
| ISSN: | 1529-2401 0270-6474 |
| DOI: | 10.1523/jneurosci.20-22-08435.2000 |
| Popis: | Thein vivoactions of insulin-like growth factor-I (IGF-I) on the growth and development of the hippocampal dentate gyrus were investigated in transgenic mice that overexpress IGF-I postnatally in the brain and in normal nontransgenic littermate controls. Stereological analyses of the dentate gyrus were performed by light and electron microscopy on days 7, 14, 21, 28, 35, and 130 to determine postnatal changes in the numerical density and total number of neurons and synapses. The volumes of both the granule cell layer and the molecular layer of the dentate gyrus were significantly increased by 27–69% in transgenic mice after day 7, with the greatest relative increases occurring by day 35. Although the numerical density of neurons in the granule cell layer did not differ significantly between transgenic and control mice at any age studied, the total number of neurons was significantly greater in transgenic mice by 29–61% beginning on day 14. The total number of synapses in the molecular layer was significantly increased by 42–105% in transgenic mice from day 14 to day 130. A transient increase in the synapse-to-neuron ratio was found in transgenic mice at postnatal days 28 and 35 but not at day 130. This finding indicates a disproportionate increase in synaptogenesis, exceeding that expected for the observed increase in neuron number. Our results demonstrate that IGF-I overexpression produces persistent increases in the total number of neurons and synapses in the dentate gyrus, indicating that IGF-I promotes both neurogenesis and synaptogenesis in the developing hippocampusin vivo. |
| Databáze: | OpenAIRE |
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