2001 Fiscal Year Final Research Report Summary
Development and maturation of glycinergic auditory pathways
| Project/Area Number |
12680730
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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 | Shiga University of Medical Science |
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Principal Investigator |
KUDO Motoi Shiga Univ. of Med. Sci., Dept. of Anatomy, Professor, 医学部, 教授 (80108141)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Takaaki Shiga Univ. of Med. Sci., Dept. of Anatomy, Research Associates, 医学部, 助手 (30314157)
KUROKAWA Kiyoshi Shiga Univ. of Med. Sci., Dept. of Anatomy, Associate Professor, 医学部, 助教授 (40215083)
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| Project Period (FY) |
2000 – 2001
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| Keywords | auditory pathway / brainstem / glycine / neurogenesis / central nervous system |
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| Research Abstract |
(1) In the immunoreactive ultrastructural study, Glycine-immunoreactive (Gly-ir) synapses seen abundantly in the inferior colliculus. About half of 891 axodendritic synapses that were identified in our study were Gly-ir. In 75 % of these Gly-ir synapses, synaptic axon terminals contained pleomorphic or flattened synaptic vesicles and made symmetric synapses, while in 25 % of Gly-ir synapses, synaptic axon terminals were filled with spherical synaptic vesicles and formed asymmetric synapses. Thus, Glycine-immunoreactivity was detected in axodendritic synapses that formed both Gray's type I and Gray's type II synapses.
(2) Neurogenesis in the superior olivary complex (SOC), which is known as a binaural comparator in the auditory brainstem, was examined in double labeling paradigm using 5-bromodeoxyuridine immunohistochemistry and retrograde transport of Fluoro-Gold. The medial nucleus (MSO) was mostly composed of neurons generated on embryonic day (E)12. The superior paraolivary (SPN) were generated with a peak on E 13. The medial trapezoid (MTB) were generated mostly on E14 Most interesting results were found in the lateral nucleus (LSO). The crossed LSO neurons were generated early (E12-E13); while uncrossed LSO neurons were generated late (E14-E16). In contrast to the previous assumption, no topographical relationship existed between neurogenesis and tonotopicity within each nucleus of the SOC.
(3) We prepared an antibody against an endtheline converting enzyme-1 (ECE-1). By the Western blot analysis, the antibody specifically recognized EE-1 proteins in membrane fractions of the rat hypothalamus. ECE-1 immunoreactivity was found in the paraventricular (PV) and supraoptic (SO) nuclei, while no immunoreactivity was detected in the posterior pituitary. Thus, ECE-1 converts the endothelin-1 (ET-1) from precursor big ET-1 to mature ET-1 in the PV/SO, while the big ET-1 existing in the posterior pituitary is escaped from the converting by ECE- 1 in the hypothalamus.
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