| Project/Area Number |
12480242
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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 | Okazaki National Research Institutes |
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Principal Investigator |
KAWAGUCHI Yasuo Okazaki National Research Institutes, National Institute for Physiological Sciences, Professor, 生理学研究所, 教授 (40169694)
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| Co-Investigator(Kenkyū-buntansha) |
KONDO Satoru Okazaki National Research Institutes, National Institute for Physiological Sciences, Research Associate, 生理学研究所, 助手 (20301757)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥14,600,000 (Direct Cost: ¥14,600,000)
Fiscal Year 2002: ¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2001: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2000: ¥8,500,000 (Direct Cost: ¥8,500,000)
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| Keywords | frontal cortex / GABA / interneuron / acetylcholine / muscarine / inhibitory synaptic current / parvalbumin / somatostatin / 錐体細胞 / バルブアルブミン / 前脳基底部 / 介在ニューロン / カルバコール / 大脳皮質 / 軸索分布 / カルシウム結合蛋白質 / シナプス結合 / スパイン |
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| Research Abstract |
To understand the characteristics of the GABAergic circuit in the rat frontal cortex, we investigated (1) the synaptic connection patterns of GABA cell subtypes, (2) cholinergic effects on the GABAergic synaptic currents, and (3) firing patterns of GABA cell subtypes during the cortical synchronized activities.
(1) FS cells innervated somata and dendritic spines as well as shafts. Somatostatin Martinotti cells innervated the dendritic shafts, and the heads and stalks of spines receiving other excitatory inputs simultaneously. The synaptic junctional area of axon terminals from FS cells linearly increased along with the circumference of postsynaptic dendrites or spines. The junctional area of axons from Martinotti cells linearly increased with the dendritic circumference or the surface area of the postsynaptic spine heads.
(2) Both carbachol and muscarine caused two temporally different patterns of inhibitory postsynaptic current modulation in cortical cells : tonic and periodic increase
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of GABA-A receptor-mediated currents. The tonic pattern features continuous increase of inhibitory current frequency, while the periodic increase manifests itself as a rhythmic burst of inhibitory postsynaptic current. In nearby cells these are synchronized as a whole but individual inhibitory events within the bursts are not always temporally linked, suggesting synchronized depolarization of several presynaptic interneurons.
(3) By lowering extracellular Mg^<2+> in vitro, we induced NMDA receptor-dependent spontaneous activities. After a series of spontaneous depolarization shifts, the long bursts occurred. The long burst composed of initial discharges and fast run-like potentials. At each phase of the synchronized activities, cortical neuron types exhibited distinct firing patterns. The firing patterns of cortical neurons are not only determined by the strength and temporal pattern of synchronized inputs, but also strongly dependent on the neuronal subtype with specific physiological, chemical and morphological characteristics. Less
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