Relationships between intracellular pH rhythms and action potential rhythms in Drosophila pacemaker neurons

2016 Fiscal Year Final Research Report

• Project/Area Number: 15H06232
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Neurophysiology / General neuroscience
• Research Institution: University of Toyama
• Principal Investigator: Morioka Eri 富山大学, 大学院理工学研究部(理学), 助教 (80756122)
• Project Period (FY): 2015-08-28 – 2017-03-31
• Keywords: 中枢時計ニューロン / キイロショウジョウバエ / 細胞内pH / 活動電位

Outline of Final Research Achievements

Drosophila circadian pacemaker neurons (LNs) exhibited unusual intracellular pH rhythms. To straightly addressed relationships between intracellular pH rhythm and action potential in LNs, I combined bio-imaging assays with an electrophysiological analysis. I found that circadian pH oscillations were specific for LNs. Using newly derived locomotor activity monitoring system, we observed significantly prolonged free-running periods in LNs-specific mitochondrial K+/H+ exchanger LETM1 knockdown flies. In addition, LETM1 knockdown reduced intracellular pH oscillation and clock protein PERIOD and TIMELESS expression rhythms.
Using newly introduced electrophysiological rigs to monitor action potentials in LNs, I found spontaneous action potential firing frequency changed according to extracellular pH conditions in control flies but not in LETM1 knockdown flies. The present study suggest that intracellular pH and mitochondrial LETM1 may be involved in circadian clock mechanisms in LNs.

Free Research Field

時間生物学