| Project/Area Number |
06808080
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nerve anatomy/Neuropathology
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| Research Institution | Wakayama Medical College |
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Principal Investigator |
KAWAI Yoshinori Wakayama Medical College, Faculty of Medicine, Lecturer, 医学部, 講師 (80211861)
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| Project Period (FY) |
1994 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1996: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1995: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1994: ¥900,000 (Direct Cost: ¥900,000)
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| Keywords | synapse / noradrenaline / dendrodendritic / symapthetic ganglion / yohimbine / hyperpolarization / superior cervical ganglion / plasticity / 抑制性伝達 / 可塑性 / カテコールアミン / 抑制性回路 / 細胞内標識 |
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| Research Abstract |
It has been considered that the sympathetic ganglion is relay station in which synaptic transmission occurs between the principal neurons and the preganglionic axons derived from the thoracic spinal cord. Using an intracellular labeling of the superior cervical ganglion (SCG) neurons with biocytin followed by electron microscopic observation of the synapses involved, I have revealed that dendrites of some SCG neurons serve as not only recipients to the preganglionic axons but also presynaptic elements to other SCG neurons. These dendrodendritic synapses should be considered as an important addition to the conventional scheme as a relay station of the sympathetic ganglion. Since the principal neurons use noradrenaline as a transmitter, these dendrodendritic synapses were interpreted as adrenergic in terms of morphology. I have revealed that in some SCG neurons hyperpolarizations are observed after the preganglionic stimulation and that this synaptically evoked hyperpolarizations are blocked by yohimbine, an alpha2-adrenoceptor antagonist. This result shows that there are adrenergic transmission in the sympathetic ganglion also in terms of pharmacology. Furthermore, these neurons have been clarified to receive dendrodendritic synapses of adrenergic type.
These dendrodendritic synapses were observed associated with specialized dendritic morphology, glomerular dendrites. I have got some evidence that these structures may show very acute plasticity. This problem should be addressed in further experiments in the near future.
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