| Affiliation: | LIANG Zhen-tao(Shenzhen Hospital, Peking University)；WANG Xian-pei(Department of Cardiology, Henan Provincial People's Hospital,Zhengzhou, Henan 450003, China)；ZENG Qiu-tang(Department of Cardiology, Institute of Cardiovascular Diseases,Ion Channelopathy Research Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology,Wuhan, Hubei 430022, China)；LIAO Yu-hua(Department of Cardiology, Institute of Cardiovascular Diseases,Ion Channelopathy Research Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology,Wuhan, Hubei 430022, China)；ZOU An-ruo(Department of Cardiology, Institute of Cardiovascular Diseases,Ion Channelopathy Research Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology,Wuhan, Hubei 430022, China)；LI Lu(Department of Cardiology, Institute of Cardiovascular Diseases,Ion Channelopathy Research Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology,Wuhan, Hubei 430022, China)；TU Dan-na(Department of Cardiology, Institute of Cardiovascular Diseases,Ion Channelopathy Research Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology,Wuhan, Hubei 430022, China)； |
| Abstract: | Background Ketanserin (KT), a selective serotonin (5-HT) 2-receptor antagonist, reduces peripheral blood pressure by blocking the activation of peripheral 5-HT receptors. In this study electrophysiological method was used to investigate the effect of KT and potassium ion on Kv1.3 potassium channels and explore the role of blocker KT in the alteration of channel kinetics contributing to the potassium ion imbalances.
Methods Kv1.3 channels were expressed in xenopus oocytes, and currents were measured using the two-microelectrode voltage-clamp technique.
Results KCl made a left shift of activation and an inactivation curve of Kv1.3 current and accelerated the activation and inactivation time constant. High extracellular [K+] attenuated the blockade effect of KT on Kv1.3 channels. In the presence of KT and KCl the activation and inactivation time constants were not influenced significantly no matter what was administered first. KT did not significantly inhibit Kv1.3 current induced by tetraethylammonium (TEA).
Conclusions KT is a weak blocker of Kv1.3 channels at different concentrations of extracellular potassium and binds to the intracellular side of the channel pore. The inhibitor KT of ion channels is not fully effective in clinical use because of high [K+]o and other electrolyte disorders. |
