1990 Fiscal Year Final Research Report Summary
Synaptic Transmission and Modulation in the Autonomic Nervous System
| Project/Area Number |
63480109
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Neurophysiology and muscle physiology
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| Research Institution | Kurume University |
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Principal Investigator |
NISHI Syogoro Kurume U. Sch. Med., Professor, 医学部, 教授 (00080557)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Eiichiro Kurume U. Sch. Med., Instructor, 医学部, 助手 (80188284)
MIHARA Satoshi Kurume U. Sch. Med., Instructor, 医学部, 助手 (40166103)
INOKUCHI Hiroe Kurume U. Sch. Med., Asst. Professor, 医学部, 講師 (10080558)
YOSHIMURA Megumu Kurume U. Sch. Med., Asst. Professor, 医学部, 講師 (10140641)
HIGASHI Hideho Kurume U. Sch. Med., Assoc. Professor, 医学部, 助教授 (10098907)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Spinal lateral horn / Fast EPSP / Slow EPSP and IPSP / Glutamate receptors / Adrenoceptors / Signal transduction / Protein kinase C / G protein |
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| Research Abstract |
1. Measurement of the release of transmitters mediating the fast EPSP (glutamate and aspartate), the slow EPSP (noradrenaline) and the slow IPSP (noradrenaline) in the spinal lateral horn cells (cat) : The spontaneous and evoked release of glutamate and aspartate from tissue slices of the lateral hoorn were measured by the gass-mass spectrometry. The release of noradrenaline from the same tissue preparation was measured by a high-pressure liquid chromatography.
2. Characterization of the receptors mediating the synaptic potentials in the lateral horn cells (cat) and analysis of the intracellular signal transduction for the slow PSPs : The glutamate receptors responsible for production of the fast EPSP were a non-NMDA type in 70% of the cells and non-NMDA plus NMDA types in 30% of the cells. Most of the fast IPSP were mediated by glycine via glycine receptors, while some of the fast IPSP were mediated by GABA through GABA-A receptors. The slow EPSP and IPSP were evoked by noradrenaline via alpha-1 and alpha-2 adrenoceptors, respectively. The former was associated with closing of Ca-dependent K channels due to activation of protein kinase C, and the latter was accompanied by opening of voltage-independent K channels due to activation of G protein.
3. Presynaptic inhibition in the lateral horn cells (cat) : The fast EPSP in these cells were inhibited presynaptically by noradrenaline. This inhibition was due to a lowering of the probability of glutamate release.
4. Intracellular signal transduction that produces the slow IPSP in Meissner's neurons of alimental canal (guinea-pig) : It was found that the outward synaptic current evoked by the transmitter noradrenaline in Meissner's neurons were produced not only by opening of K channels triggered by activated G protein but also by activation of Ca-dependent K channels that occurred simultaneously with the former.
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