title: Tannic acid activates the Kv7.4 and Kv7.3/7.5 K(+) channels expressed in HEK293 cells and reduces tension in the rat mesenteric arteries.
abstract: OBJECTIVE
  This study investigated the effect of tannic acid (TA), a plant-derived hydrolyzable polyphenol, on Kv7.4 and Kv7.5 K(+) channels and rat mesenteric artery.
  
  
  METHODS
  Whole-cell patch clamp experiments were used to record the Kv7.4 and Kv7.3/7.5 K(+) currents expressed in HEK293 cells; and the tension changes of mesenteric arteries isolated from rats were recorded using small vessel myography apparatus.
  
  
  RESULTS
  Tannic acid increases the Kv7.4 and Kv7.3/7.5 K(+) currents in a concentration-dependent manner (median effective concentration (EC50 ) = 27.3 ± 3.6 μm and EC50 = 23.1 ± 3.9 μm, respectively). In addition, 30 μm TA shifts the G-V curve of Kv7.4 and Kv7.3/7.5 K(+) currents to the left by 14.18 and 25.24 mV, respectively, and prolongs the deactivation time constants by 184.44 and 154.77 ms, respectively. Moreover, TA relaxes the vascular tension of rat mesenteric arteries in a concentration-dependent manner (half inhibitory concentration (IC50 ) = 148.7 ± 13.4 μm).
  
  
  CONCLUSIONS
  These results confirms the vasodilatory effects of TA on rat mesenteric artery and the activating effects on the Kv7.4 and Kv7.3/7.5 K(+) channels, which may be a mechanism to explain the vasodilatory effect and this mechanism can be used in the research of antihypertension.
authors.affiliation: Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Pharmacy, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Chu
authors.affiliation: Department of Pharmacy, Maternal and Child Health Hospital, Tangshan, Hebei, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.affiliation: Vascular Surgery, The East Branch of Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Guo
authors.affiliation: Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China.
authors.forename: Zhenyi
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Intensive Care Unit, Air Force General Hospital, Beijing, Jiangsu, China.
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Key Laboratory of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, Jiangsu, China.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Bao
authors.affiliation: Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D057809:HEK293 Cells; D006801:Humans; D066298:In Vitro Techniques; D051656:KCNQ Potassium Channels / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D051659:KCNQ3 Potassium Channel / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials; D008638:Mesenteric Arteries / Q000187:drug effects*; D009213:Myography; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D017207:Rats, Sprague-Dawley; D013634:Tannins / Q000494:pharmacology*; D013997:Time Factors; D014162:Transfection; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D000959:Antihypertensive Agents; D051656:KCNQ Potassium Channels; D051659:KCNQ3 Potassium Channel; C496916:KCNQ3 protein, human; C117367:KCNQ4 protein, human; C412231:KCNQ5 protein, human; D026902:Potassium Channel Blockers; D013634:Tannins; D014665:Vasodilator Agents
keywords: K+ channels; antihypertension; tannic acid; vascular tension