Regulatory mechanism of neurotransmission by vesicular nucleotide transporter in carotid body chemoreceptor cells

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K16482
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 48010:Anatomy-related
• Research Institution: Iwate Medical University
• Principal Investigator: YOKOYAMA Takuya 岩手医科大学, 医学部, 講師 (70772094)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 頚動脈小体 / 免疫組織化学 / 小胞型ヌクレオチド輸送体 / ATP

Outline of Final Research Achievements

Adenosine 5'-triphosphate (ATP) is the neurotransmitter from chemoreceptor cells to sensory nerve endings in the carotid body. The present study investigated mRNA expression and immunohistochemical localization of VNUT, the vesicle loading protein for exocytosis of ATP, in the rat carotid body. RT-PCR analysis detected the expression of mRNA for VNUT, in extracts of the carotid body. Immunohistochemistry detected the immunoreactivity for VNUT in 23.1% of chemoreceptor cells. Furthermore, VNUT immunoreactivity was selectively localized in chemoreceptor cells surrounded by sensory nerve endings immunoreactive for P2X3 purinoceptors. These findings revealed the selective localization of VNUT in the subpopulation of chemoreceptor cells receiving sensory innervation and suggested that suggest these cells release ATP by exocytosis for chemosensory transmission in the carotid body.

Free Research Field

組織学

Academic Significance and Societal Importance of the Research Achievements

頚動脈小体の化学受容細胞は神経伝達物質ATPを分泌する機能的に同一な細胞集団とみなされており、その分泌機構を追究した研究はなかった。本研究は、VNUTを発現する化学受容細胞のみが低酸素の情報を伝達しているという新たな機能局在性の可能性を示した。今後、VNUTが化学受容細胞においてATPの小胞内蓄積と分泌を制御している事実を捉えることができれば、低酸素に対する呼吸反射経路の起動に関わる重要な知見を示すことができる。