title: Enhanced transient receptor potential channel-mediated Ca2+influx in the cells with phospholipase C-δ1 overexpression: its possible role in coronary artery spasm.
abstract: We reported that coronary spasm was induced in the transgenic mice with the increased phospholipase C (PLC)-δ1 activity. We investigated the effect of enhanced PLC-δ1 on Ca2+influx and its underlying mechanisms. We used human embryonic kidney (HEK)-293 and coronary arteries smooth muscle cells (CASMC). Intracellular free Ca2+concentration ([Ca2+]i; nm) was measured by fura-2, and Ca2+influx was evaluated by the increase in [Ca2+]iafter addition of extracellular Ca2+. Acetylcholine (ACh) was used to induce Ca2+influx. ACh-induced peak Ca2+influx was 19 ± 3 in control HEK-293 cells and 71 ± 8 in the cells with PLC-δ1 overexpression (P < 0.05 between two groups). Nifedipine partially suppressed this Ca2+influx, whereas either 2-APB or knockdown of classical transient receptor potential channel 6 (TRPC6) blocked this Ca2+influx. In the human CASMC, ACh-induced peak Ca2+influx was 29 ± 6 in the control and was increased to 45 ± 16 by PLC-δ1 overexpression (P < 0.05). Like HEK-293 cells, pretreatment with nifedipine partially suppressed Ca2+influx, whereas either 2-APB or knockdown of TRPC6 blocked it. ACh-induced Ca2+influx was enhanced by PLC-δ1 overexpression, and was blocked partially by nifedipine and completely by 2-APB. TRPC-mediated Ca2+influx may be related to the enhanced Ca2+influx in PLC-δ1 overexpression.
authors.affiliation: Department of Cardiology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho Hirosaki, Hirosaki, Aomori Prefecture, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Murakami
authors.affiliation: Department of Nursing, Hirosaki University Graduate School of Health Science, 66-1 Hon-cho Hirosaki, Hirosaki, Aomori Prefecture, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Osanai
authors.affiliation: Department of Hypertension and Stroke Internal Medicine, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho Hirosaki, Hirosaki, Aomori Prefecture, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Department of Cardiology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho Hirosaki, Hirosaki, Aomori Prefecture, Japan.
authors.forename: Kimitaka
authors.initials: K
authors.lastname: Nishizaki
authors.affiliation: Department of Cardiology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho Hirosaki, Hirosaki, Aomori Prefecture, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Kinjo
authors.affiliation: Department of Cardiology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho Hirosaki, Hirosaki, Aomori Prefecture, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Tanno
authors.affiliation: Department of Cardiology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho Hirosaki, Hirosaki, Aomori Prefecture, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ishida
authors.affiliation: Department of Cardiology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho Hirosaki, Hirosaki, Aomori Prefecture, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Department of Cardiology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho Hirosaki, Hirosaki, Aomori Prefecture, Japan.
authors.forename: Tomohide
authors.initials: T
authors.lastname: Endo
authors.affiliation: Department of Cardiology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho Hirosaki, Hirosaki, Aomori Prefecture, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Tomita
authors.affiliation: Division of Cardiology, Saiseikai Kumamoto Hospital, 5-3-1 Chikami Minamiku Kumamoto, Kumamoto, Kumamoto Prefecture, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Okumura
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D003329:Coronary Vasospasm / Q000201:enzymology* / Q000235:genetics; D003331:Coronary Vessels / Q000187:drug effects / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D057809:HEK293 Cells; D006801:Humans; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000201:enzymology; D054803:Phospholipase C delta / Q000096:biosynthesis* / Q000235:genetics; D000074287:TRPC6 Cation Channel / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D002121:Calcium Channel Blockers; D000074287:TRPC6 Cation Channel; C117032:TRPC6 protein, human; D054803:Phospholipase C delta; D002118:Calcium
keywords: Intracellular Ca2+ concentration; PLC-δ1; coronary spasm; transient receptor potential channel 6