| Project/Area Number |
61480082
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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 |
基礎獣医学
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| Research Institution | Hokkaido University |
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Principal Investigator |
ITO shigeo Fac. of Veterinary Medicine, Hokkaido Univ., 獣医学部, 助手 (40109509)
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| Co-Investigator(Kenkyū-buntansha) |
OHTA Toshio Fac. of Veterinary Medicine, Hokkaido Univ., 獣医学部, 助手 (20176895)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1987: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1986: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Keywords | 潅流副腎髄質 / 分離副腎髄質細胞 / ニコチン受容体 / ムスカリン受容体 / イノシトール・三リン酸 / ホルボールエステル / FuraIIAM / 細胞内Ca^<2+>濃度 / 灌流副腎髄質 / イノシトール・ミリン酸 / Fre【II】 / Fre【II】AM / 細胞内Ca濃度 |
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| Research Abstract |
The purpose of the present experiments was to study the mechanisms of muscarinic receptor-mediated catecholamine secretion in adrenal chromaffin cells. Nicotinic receptors were only the receptor type associated with Ach-induced ctecholamine secretion from adrenal chromaffin cells in the goat and pig and both nicotinic and muscarinic receptors in the guinea-pig, cat and dog. The muscarinic receptormediated catecholamine secretion was not dependent on either changes in membrane potential or extracellular Ca^<2+>in guinea-pig perfused adrenal glands. The muscarinic response was inhibited by intracellula Ca antaonist, TMB-8. The muscarinic response was poentiated by Li+ which inhibits phosphatidilinositol breakdown and unaffected by protein kinase C activator, TPA. Furthemore, the secretory response to ACh was accompanied by the increase in intracellular Ca^<2+>measured by FuraII fluorescence. These results suggest that the muscarinic receptor activation causes an increase in catecholamine secretion by releasing Ca^<2+>from intracellular Ca^<2+>store sites through phophatidylinositol breakdown. In order to syudy the intracellular mechanisms of the muscarinic receptor-mediated catecholamine secretion, adrenal chromaffin cells were isolated by digestion with collagenase and purified with percoll density gradient centrifugation. Eighty % of isolated cells were identified as chromaffin cells by using neutral red staining and anti dopamine-<beta>-hydroxylase immunofluorescent staining. These purisied chromaffin cells released catecholamine in response to ACh in the presence of Ca^<2+>but not in the absence of extracellular Ca^<2+>. Further studies for isolating intact chromaffin cells are now onging.
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