| Project/Area Number |
11480242
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Neuroscience in general
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| Research Institution | Tokyo Metropolitan Institute of Gerontology (TMIG) |
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Principal Investigator |
AOSAKI Toshihiko Tokyo Metropolitan Institute of Gerontology, Dept Autonomic Nervous System, Head, 自律神経部門, 研究室長 (70221033)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥8,100,000 (Direct Cost: ¥8,100,000)
Fiscal Year 2000: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1999: ¥5,300,000 (Direct Cost: ¥5,300,000)
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| Keywords | striatum / memory / cholinergic / learning / procedural / dopamine / basal ganglia / patch clamp / アセチルコリン / 長期抑圧 / 長期増強 |
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| Research Abstract |
The striatum, the input stage of the basal ganglia, is a critical brain structure for the learning of stimulus-response habits as well as motor, perceptual, and congnitive skills. Roles of dopamine (DA) and acetylcholine (ACh) in this form of implicit memory have long been considered essential, but the underlying cellular mechanism is still unclear. By means of patch clamp recordings from corticostriatal slices of the mouse, we studied whether the identified striatal cholinergic interneurons undergo long-term synaptic changes after tetanic stimulation of cortico and thalamostriatal fibers. Electrical stimulation of the fibers revealed a depolarizing and hyperpolarizing postsynaptic potential in the striatal cholineergic interneurons. The early depolarizing phase was considered as a cortico/thalamostriatal glutamatergic EPSP and the hyperpolarizing component as an intrastriatally-evoked GABAergic IPSP.Tetanic stimulation of cortico/thalamostriatal fibers was found to induce simultaneously occurring long-term potentiation (LTP) of the EPSPs as well as the disynaptically-mediated IPSPs. The induction of LTP of EPSP required a rise in intracellular Ca2+ concentration and dopamine D5, but not D2 receptor activation. Blockade of neither NMDA receptors, metabotropic glutamate receptors nor Ca2+ -permeable AMPA receptors had any significant effects. The long-term enhancement of the disynaptic IPSPs was due to a long-term increase in the occurrence rate, but not the amplitude of disynaptically-mediated IPSP in the striatal cholinergic interneurons. This dual mechanism of synaptic plasticity may be responsible for the long-term modulation of the cortico/thalamostriatal synaptic transmission.
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