1. Academic Validation
  2. High Efficacy by GAL-021: A Known Intravenous Peripheral Chemoreceptor Modulator that Suppresses BKCa-Channel Activity and Inhibits IK(M) or Ih

High Efficacy by GAL-021: A Known Intravenous Peripheral Chemoreceptor Modulator that Suppresses BKCa-Channel Activity and Inhibits IK(M) or Ih

  • Biomolecules. 2020 Jan 25;10(2):188. doi: 10.3390/biom10020188.
Te-Ling Lu 1 Zi-Han Gao 2 Shih-Wei Li 2 Sheng-Nan Wu 2 3 4
Affiliations

Affiliations

  • 1 School of Pharmacy, China Medical University, Taichung City 40402, Taiwan.
  • 2 Department of Physiology, National Cheng Kung University Medical College, Tainan City 70101, Taiwan.
  • 3 Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan City 70701, Taiwan.
  • 4 Department of Medical Research, China Medical University Hospital, China Medical University, Taichung City 40402, Taiwan.
Abstract

: GAL-021 has recently been developed as a novel breathing control modulator. However, modifications of ionic currents produced by this agent remain uncertain, although its efficacy in suppressing the activity of big-conductance Ca2+-activated K+ (BKCa) channels has been reported. In pituitary tumor (GH3) cells, we found that the presence of GAL-021 decreased the amplitude of macroscopic Ca2+-activated K+ current (IK(Ca)) in a concentration-dependent manner with an effective IC50 of 2.33 μM. GAL-021-mediated reduction of IK(Ca) was reversed by subsequent application of verteporfin or ionomycin; however, it was not by that of diazoxide. In inside-out current recordings, the addition of GAL-021 to the bath markedly decreased the open-state probability of BKCa channels. This agent also resulted in a rightward shift in voltage dependence of the activation curve of BKCa channels; however, neither the gating charge of the curve nor single-channel conductance of the channel was changed. There was an evident lengthening of the mean closed time of BKCa channels in the presence of GAL-021, with no change in mean open time. The GAL-021 addition also suppressed M-type K+ current with an effective IC50 of 3.75 μM; however, its presence did not alter the amplitude of erg-mediated K+ current, or mildly suppressed delayed-rectifier K+ current. GAL-021 at a concentration of 30 μM could also suppress hyperpolarization-activated cationic current. In HEK293T cells expressing α-hSlo, the addition of GAL-021 was also able to suppress the BKCa-channel open probabilities, and GAL-021-mediated suppression of BKCa-channel activity was attenuated by further addition of BMS-191011. Collectively, the GAL-021 effects presented herein do not exclusively act on BKCa channels and these modifications on ionic currents exert significant influence on the functional activities of electrically excitable cells occurring in vivo.

Keywords

Ca2+-activated K+ current; GAL-021; M-type K+ current; large-conductance Ca2+-activated K+ channel; pituitary tumor cells; -hSlo.

Figures
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    Product Name
    Description
    Target
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  • HY-101422
    99.89%, BKCa-Channel Blocker