Published online Aug 7, 2017. doi: 10.3748/wjg.v23.i29.5313
Peer-review started: March 4, 2017
First decision: April 6, 2017
Revised: April 18, 2017
Accepted: June 9, 2017
Article in press: June 12, 2017
Published online: August 7, 2017
To investigate the effects of a water extract of Hwangryunhaedok-tang (HHTE) on the pacemaker potentials of mouse interstitial cells of Cajal (ICCs).
We dissociated ICCs from small intestines and cultured. ICCs were immunologically identified using an anti-c-kit antibody. We used the whole-cell patch-clamp configuration to record the pacemaker potentials generated by cultured ICCs under the current clamp mode (I = 0). All experiments were performed at 30 °C-32 °C
HHTE dose-dependently depolarized ICC pacemaker potentials. Pretreatment with a 5-HT3 receptor antagonist (Y25130) or a 5-HT4 receptor antagonist (RS39604) blocked HHTE-induced pacemaker potential depolarizations, whereas pretreatment with a 5-HT7 receptor antagonist (SB269970) did not. Intracellular GDPβS inhibited HHTE-induced pacemaker potential depolarization and pretreatment with a Ca2+-free solution or thapsigargin abolished the pacemaker potentials. In the presence of a Ca2+-free solution or thapsigargin, HHTE did not depolarize ICC pacemaker potentials. In addition, HHTE-induced pacemaker potential depolarization was unaffected by a PKC inhibitor (calphostin C) or a Rho kinase inhibitor (Y27632). Of the four ingredients of HHT, Coptidis Rhizoma and Gardeniae Fructus more effectively inhibited pacemaker potential depolarization.
These results suggest that HHTE dose-dependently depolarizes ICC pacemaker potentials through 5-HT3 and 5-HT4 receptors via external and internal Ca2+ regulation and via G protein-, PKC- and Rho kinase-independent pathways.
Core tip: Hwangryunhaedok-tang, a traditional herbal medicine, has been used to treat gastrointestinal diseases. Our data suggest that HHT can depolarize the pacemaker potentials of cultured interstitial cells of Cajal from mouse small intestine and may be a novel prokinetic agent.