Behavioral analyses and ligand screening toward the identification of the physiological roles of an orphan metabotropic receptor Prrt3

2019 Fiscal Year Annual Research Report

• Project/Area Number: 18K15020
• Research Institution: National Institute for Physiological Sciences
• Principal Investigator: 陳 以珊 生理学研究所, 分子細胞生理研究領域, 特任助教 (40757770)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Keywords: Orphan GPCR

Outline of Annual Research Achievements

Prrt3 is an orphan metabotropic receptor of family C GPCR and there is no publication concerning Prrt3. We have observed that Prrt3 is highly expressed in mouse brain. Since the physiological roles of Prrt3 are still unknown, we aim to identify the endogenous ligands of Prrt3 and elucidate the roles of Prrt3 in the central nervous system (CNS).We have performed behavioral analyses using homozygous Prrt3 knockout (KO) mice and electrophysiological experiments using Xenopus oocytes, and we observed the following results:
(1) We created homozygous Prrt3 KO mice and performed behavioral analyses. By the Barnes probe test to analyze the spatial memory, we observed a significant decrease in the retention of spatial memory after 4 weeks interval from the completion of training. The scores of homo Prrt3 KO mice of Latency to the 1st arrival at the target hole, Error to 1st and Distance to 1st were all significantly higher than those of control mice.
(2) By monitoring GIRK currents, we screened several types of small-molecule libraries and observed that some muscarinic receptor agonists, but not ACh, slightly activates the Prrt3. We also happened to identify several novel inhibitors of GIRK channel, such as antihistamine drugs. We clarified the inhibition mechanisms of GIRK channel by these drugs and published the data and results in British Journal of Pharmacology. These results provide us with clues toward the understanding of physiological roles of Prrt3.

Research Products

• [Journal Article] Non-sedating antihistamines block G-protein-gated inwardly rectifying K+ channels (2019)
  • Author(s): I-Shan Chen, Chang Liu, Michihiro Tateyama, Izhar Barbat, Motonari Uesugi, Eitan Reuveny, Yoshihiro Kubo
  • Journal Title: British Journal of Pharmacology Volume: 176 Pages: 3161-3179
  • DOI: 10.1111/bph.14717
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Inhibitory mechanisms of G-protein-gated inwardly rectifying K+ channel by antihistamines (2020)
  • Author(s): I-Shan Chen, Chang Liu, Michihiro Tateyama, Izhar Barbat, Motonari Uesugi, Eitan Reuveny, Yoshihiro Kubo
  • Organizer: The 64th Annual Meeting of the Biophysical Society
  • Int'l Joint Research
• [Presentation] Physiological roles of Prrt3, an orphan metabotropic receptor: Comprehensive behavioral test battery analysis using homozygous full gene knock-out mice derived from flox mice (2020)
  • Author(s): Tomomi Yamamoto, Satoko Hattori, Li Zhou, Rie Natsume, Kohtarou Konno, I-Shan Chen, Masahiko Watanabe, Kenji Sakimura, Tsuyoshi Miyakawa, Yoshihiro Kubo
  • Organizer: 第97回日本生理学会大会
• [Remarks] 非鎮静性抗ヒスタミン薬によるGIRKチャネルの活性阻害機構の解明
  • URL: http://www.nips.ac.jp/nips_research/2019/07/girk_1.html