Activation of Voltage-Gated Na+ Current by GV-58, a Known Activator of CaV Channels

Hsin Yen Cho, Pei Chun Chen, Tzu Hsien Chuang, Meng Cheng Yu, Sheng Nan Wu

研究成果: Article同行評審

摘要

GV-58 ((2R)-2-[(6-{[(5-methylthiophen-2-yl)methyl]amino}-9-propyl-9H-purin-2-yl)amino] butan-1-ol) is recognized to be an activator of N-and P/Q-type Ca2+ currents. However, its modula-tory actions on other types of ionic currents in electrically excitable cells remain largely unanswered. This study was undertaken to explore the possible modifications caused by GV-58 in ionic currents (e.g., voltage-gated Na+ current [INa ], A-type K+ current [IK(A) ], and erg-mediated K+ current [IK(erg) ]) identified from pituitary GH3 lactotrophs. GH3 cell exposure to GV-58 enhanced the transient and late components of INa with varying potencies; consequently, the EC50 values of GV-58 required for its differential increase in peak and late INa in GH3 cells were estimated to be 8.9 and 2.6 µM, respectively. The INa in response to brief depolarizing pulse was respectively stimulated or sup-pressed by GV-58 or tetrodotoxin, but it failed to be altered by ω-conotoxin MVIID. Cell exposure to this compound increased the recovery of INa inactivation evoked by two-pulse protocol based on a geometrics progression; however, in its presence, there was a slowing in the inactivation rate of current decay evoked by a train of depolarizing pulses. The existence of GV-58 also resulted in an increase in the amplitude of ramp-induced resurgent and window INa . The presence of this compound inhibited IK(A) magnitude, accompanied by a shortening in inactivation time course of the current; however, it mildly decreased IK(erg) . Under current-clamp conditions, GV-58 increased the frequency of spontaneous action potentials in GH3 cells. Moreover, in NSC-34 motor neuron-like cells, the presence of GV-58 not only raised INa amplitude but also reduced current inactivation. Taken together, the overall work provides a noticeable yet unidentified finding which implies that, in addition to its agonistic effect on Ca2+ currents, GV-58 may concertedly modify the amplitude and gating kinetics of INa in electrically excitable cells, hence modifiying functional activities in these cells.

原文English
文章編號721
期刊Biomedicines
10
發行號3
DOIs
出版狀態Published - 2022 3月

All Science Journal Classification (ASJC) codes

  • 醫藥(雜項)
  • 生物化學、遺傳與分子生物學 (全部)

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