1999 Fiscal Year Final Research Report Summary
Cortical GABAergic Cell Subtypes and Their Synaptic Connections
| Project/Area Number |
09480235
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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 (1999)
The Institute of Physical and Chemical Research (1997-1998) |
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Principal Investigator |
KAWAGUCHI Yasuo National Institute for Physiological Science, Laboratory of Cerebral Circuitry, Professor, 生理学研究所, 教授 (40169694)
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| Co-Investigator(Kenkyū-buntansha) |
KUBOTA Yoshiyuki The Institute of Physical and Chemical Research, Lab. For Neural Circuits, Frontier researcher, 運動回路網研究チーム, 研究員 (90192567)
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| Project Period (FY) |
1997 – 1999
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| Keywords | cortex / GABA / cholecystokinin / somatostatin / parvalbumin / basket cell / acetylcholine / noradrenaline |
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| Research Abstract |
Cortical GABAergic Cell Subtypes and Their Synaptic Connections
Physiological, morphological immunohistochemical and pharmacological characteristics of GABAergic cells in rat frontal cortex of rats were studied in vitro. (1) Physiological and chemical heterogeneity of large GABAergic basket cells. Cholecystokinin (CCK) cells and parvalbumin cells made boutons apposed to other cell bodies. Parvalbumin cells belonged to fast-spiking (FS) cells. In contrast, CCK cells were found to be regular-spiking (RS) or burst-spiking (BS) nonpyramidal (NP) cells. Large somatostatin cells belonged to the RSNP category which did not seem to be apposed to the somata so frequently as large CCK and parvalbumin cells. (2) Selective cholinergic modulation of cortical GABAergic cell subtypes. Cholinergic or muscarinic agonists indeed induced GABAergic postsynaptic currents in pyramidal cells by exciting inhibitory interneurons. Carbachol or muscarine affected the activities of peptide-containing GABAergic cel
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ls, but not of GABAergic cells of fast-spiking characteristics containing parvalbumin and GABAergic cells of late-spiking characteristics. Somatostatin or VIP cells were depolarized with spike firing. CCK cells were affected heterogeneously by cholinergic agonists. Larger CCK cells were hyperpolarized followed by a slow depolarization, whereas smaller CCK cells were only depolarized. (3) Noradrenergic excitation and inhibition of GABAergic cell types. Noradrenaline (NA) and an a-adrenergic agonist, 6 fluoronorepinephrine (FNE) induced an increase of IPSC frequency in pyramidal cells, but not a b-adrenergic agonist. This increase was reduced by tetrodotoxin, bicuculline and a-adrenergic antagonists, suggesting that GABAergic cells are excited via a-adrenoceptors. Fast spiking or late spiking cells were depolarized by application of NA or FNE, but none demonstrated spike firings. Most somatostatin cells were depolarized, accompanied by spike firing. In a few cases this was preceded by hyperpolarization. Cholecystokinin cells were affected heterogeneously: depolarization, hyperpolarization followed by depolarization, or hyperpolarization resulted. Less
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