Relationship between receptor expression revaled by rhodamine-labeled peptides and calcium responses in cortical neurons

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K15783
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Functional basic dentistry
• Research Institution: Nihon University
• Principal Investigator: KOBAYASHI Masayuki 日本大学, 歯学部, 教授 (00300830)
• Co-Investigator(Kenkyū-buntansha): 長谷川 功紀 京都薬科大学, 薬学部, 准教授 (50525798) ; 崔 翼龍 国立研究開発法人理化学研究所, ライフサイエンス技術基盤研究センター, ユニットリーダー (60312229)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: オレキシン / 島皮質 / カルシウム・イメージング / Gタンパク質 / ローダミン / 受容体

Outline of Final Research Achievements

Neural responses to a ligand exhibit a wide variation from neuron to neuron, however, underling mechanisms of the response variation remains unclear. One possible mechanism is a variation of the number of receptors expressed in each neural membrane. To examine this hypothesis, we synthesized rhodamine-labeled orexin A compound, which enabled us to quantify the amount of orexin binding to orexin receptors, OX1 and OX2. Application of rhodamine-labeled orexin A to the cortical surface heterogeneously increased both the intensity of the rhodamine fluorescence and [Ca2+]i. We classified neurons into high- and low-responding neurons based on the peak amplitude of [Ca2+]i increase. Intensity of the rhodamine fluorescence in high-responding neurons was significantly larger than that in low-responding neurons. These results suggest that a part of mechanisms for varying neural responses including [Ca2+]i increases are the diversity of the amount of receptor expression in the neural membrane.

Free Research Field

神経生理学