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Kang M, An JR, Li H, Zhuang W, Heo R, Park S, Mun SY, Park M, Seo MS, Han ET, Han JH, Chun W, Park WS. Blockade of voltage-dependent K+ channels by benztropine, a muscarinic acetylcholine receptor inhibitor, in coronary arterial smooth muscle cells. Toxicol Sci 2022; 189:260-267. [PMID: 35944222 DOI: 10.1093/toxsci/kfac083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We investigated the effect of the acetylcholine muscarinic receptor inhibitor benztropine on voltage-dependent K+ (Kv) channels in rabbit coronary arterial smooth muscle cells. Benztropine inhibited Kv currents in a concentration-dependent manner, with an apparent IC50 value of 6.11 ± 0.80 μM and Hill coefficient of 0.62 ± 0.03. Benztropine shifted the steady-state activation curves toward a more positive potential, and the steady-state inactivation curves toward a more negative potential, suggesting that benztropine inhibited Kv channels by affecting the channel voltage sensor. Train pulse (1 or 2 Hz)-induced Kv currents were effectively reduced by the benztropine treatment. Furthermore, recovery time constants of Kv current inactivation increased significantly in response to benztropine. These results suggest that benztropine inhibited vascular Kv channels in a use (state)-dependent manner. The inhibitory effect of benztropine was canceled by pretreatment with the Kv 1.5 inhibitor, but there was no obvious change after pretreatment with Kv 2.1 or Kv7 inhibitors. In conclusion, benztropine inhibited the Kv current in a concentration- and use (state)-dependent manner. Inhibition of the Kv channels by benztropine primarily involved the Kv1.5 subtype. Restrictions are required when using benztropine to patients with vascular disease.
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Affiliation(s)
- Minji Kang
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Jin Ryeol An
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Hongliang Li
- Institute of Translational Medicine, Medical College, Jiangsu Key laboratory of integrated traditional Chinese and Western Medicine for prevention and treatment of Senile Diseases, Yangzhou University, Yangzhou, 225001, PR China
| | - Wenwen Zhuang
- Institute of Translational Medicine, Medical College, Jiangsu Key laboratory of integrated traditional Chinese and Western Medicine for prevention and treatment of Senile Diseases, Yangzhou University, Yangzhou, 225001, PR China
| | - Ryeon Heo
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Seojin Park
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Seo-Yeong Mun
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Minju Park
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Mi Seon Seo
- Department of Physiology, Konkuk University School of Medicine, Chungju, 27478, South Korea
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Jin-Hee Han
- Department of Medical Environmental Biology and Tropical Medicine, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Wanjoo Chun
- Department of Pharmacology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Won Sun Park
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
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Inhibitory Effectiveness in Delayed-Rectifier Potassium Current Caused by Vortioxetine, Known to Be a Novel Antidepressant. Biomedicines 2022; 10:biomedicines10061318. [PMID: 35740340 PMCID: PMC9220334 DOI: 10.3390/biomedicines10061318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/25/2022] [Accepted: 06/01/2022] [Indexed: 01/27/2023] Open
Abstract
Vortioxetine (VOR) is recognized to exert antidepressant actions. However, whether this drug modifies ionic currents in excitable cells remains unclear. The aim of this study was to explore the electrophysiological effects of VOR and other related compounds in pituitary GH3 cells and in Neuro-2a cells. VOR suppressed the delayed-rectifier K+ current (IK(DR)) in a concentration-, time-, and state-dependent manner. Effective IC50 values needed to inhibit peak and sustained IK(DR) were computed to be 31.2 and 8.5 μM, respectively, while the KD value estimated from minimal binding scheme was 7.9 μM. Cell exposure to serotonin (10 μM) alone failed to alter IK(DR), while fluoxetine (10 μM), a compound structurally similar to VOR, mildly suppressed current amplitude. In continued presence of VOR, neither further addition of propranolol nor risperidone reversed VOR-mediated inhibition of IK(DR). Increasing VOR concentration not only depressed IK(DR) conductance but also shifted toward the hyperpolarized potential. As the VOR concentration was raised, the recovery of IK(DR) block became slowed. The IK(DR) activated by a downsloping ramp was suppressed by its presence. The inhibition of IK(DR) by a train pulse was enhanced during exposure to VOR. In Neuro-2a cells, this drug decreased IK(DR). Overall, inhibitory effects of VOR on ionic currents might constitute another underlying mechanism of its actions.
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An JR, Seo MS, Jung HS, Heo R, Kang M, Han ET, Park H, Jung WK, Choi IW, Park WS. Inhibition by Imipramine of the Voltage-Dependent K+ Channel in Rabbit Coronary Arterial Smooth Muscle Cells. Toxicol Sci 2020; 178:302-310. [PMID: 33010168 DOI: 10.1093/toxsci/kfaa149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Imipramine, a tricyclic antidepressant, is used in the treatment of depressive disorders. However, the effect of imipramine on vascular ion channels is unclear. Therefore, using a patch-clamp technique we examined the effect of imipramine on voltage-dependent K+ (Kv) channels in freshly isolated rabbit coronary arterial smooth muscle cells. Kv channels were inhibited by imipramine in a concentration-dependent manner, with an IC50 value of 5.55 ± 1.24 µM and a Hill coefficient of 0.73 ± 0.1. Application of imipramine shifted the steady-state activation curve in the positive direction, indicating that imipramine-induced inhibition of Kv channels was mediated by influencing the voltage sensors of the channels. The recovery time constants from Kv-channel inactivation were increased in the presence of imipramine. Furthermore, the application of train pulses (of 1 or 2 Hz) progressively augmented the imipramine-induced inhibition of Kv channels, suggesting that the inhibitory effect of imipramine is use (state) dependent. The magnitude of Kv current inhibition by imipramine was similar during the first, second, and third depolarizing pulses. These results indicate that imipramine-induced inhibition of Kv channels mainly occurs in the closed state. The imipramine-mediated inhibition of Kv channels was associated with the Kv1.5 channel, not the Kv2.1 or Kv7 channel. Inhibition of Kv channels by imipramine caused vasoconstriction. From these results, we conclude that imipramine inhibits vascular Kv channels in a concentration- and use (closed-state)-dependent manner by changing their gating properties regardless of its own function.
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Affiliation(s)
| | | | | | | | | | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine
| | - Hongzoo Park
- Department of Urology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Won-Kyo Jung
- Department of Biomedical Engineering, and Center for Marine-Integrated Biomedical Technology (BK21 Plus), Pukyong National University, Busan 48513, South Korea
| | - Il-Whan Choi
- Department of Microbiology, College of Medicine, Inje University, Busan 48516, South Korea
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