| Project/Area Number |
16570060
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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 |
Animal physiology/Animal behavior
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| Research Institution | Tokyo Gakugei University |
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Principal Investigator |
YOSHINO Masami Tokyo Gakugei University, Department of Education, Professor, 教育学部, 教授 (20175681)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2005: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2004: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Insect / Gryllus bimaculatus / L-type Ca channel / Ca activated K channel / Kenyon cell / Mushroom body / cAMP / Ionic channel / cAMP / P / QタイプCaチャネル / LタイプCaチャネル / パッチクランプ / ベラパミル |
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| Research Abstract |
The single Ca^<2+> channel activity was obtained from cell-attached patch recordings with the use of pipettes filled with 100 mM Ba^<2+> as the charge carrier in Kenyon cells isolated from the mushroom body of the cricket Gryllus bimaculatus. Unitary Ba^<2+> currents with brief opening times and small amplitudes were observed upon step depolarizations. From the current-voltage relationships for these currents, the single channel conductance was estimated to be about 21 pS. In the presence of (±) BayK 8644, the dihydropyridine (DHP) Ca agonist, the unitary currents with long open times were frequently observed. (-)Bay K 8644 also caused a similar change but another L-type Ca^<2+> channel activator FPL64176 had little effect. The mean current reconstructed by averaging individual current traces inactivated slowly. These results indicate that Ca channels in Kenyon cells are DHP-sensitive. Bath application of 1 mM 8bromo cAMP decreased the open probability of single Ca channels. Also the single channel conductance increased by about two times with the application of 8bromo cAMP. These results indicate that a possible inhibitory action of cAMP to the L-type Ca channels in Kenyon cells. Cell-attached patch clamp recordings with 140 mM KCl indicated the the presence 140 pS channel. The reversal potential for these currents shifted according to the Nernst equation by changing the extracellar K.concentration The amplitude for these currents was reduced with the extracellular application of TEA. Interestingly, a typical blocker of a large conductance Ca^<2+> activated K^+ channel, iberiotoxin had little effect on the unitary current activity.
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