Journal Article Role of Protein Kinase C in Acetylcholine-Induced Ca2+ Influx under Enhanced Phospholipase C-δ1

Murakami, Kazuo  ,  Osanai, Tomohiro  ,  Tanaka, Makoto  ,  Kinjo, Takahiko  ,  Tanno, Tomohiro  ,  Narita, Ikuyo  ,  Kawai, Misato  ,  Tomita, Hirofumi  ,  Okumura, Ken

66 ( 1 )  , pp.22 - 27 , 2015-04-06 , 弘前大学大学院医学研究科・弘前医学会
Background: We reported that enhanced phospholipase C (PLC)-δ1, which was detected in patients with coronary spasm, caused coronary spasm in mice. We investigated the role of protein kinase C( PKC) in acetylcholine (ACh)-induced Ca2+ influx under enhanced PLC-δ1 using human embryonic kidney( HEK)-293 cells. Methods and Results: Intracellular free Ca2+ concentration ([Ca2+]i) was measured by fura-2, and Ca2+ influx was evaluated by the increase in [Ca2+]i after addition of extracellular Ca2+. ACh-induced Ca2+ influx( nM) in HEK-293 cells was 21±2 in control HEK-293 cells, 52±6 in the cells with PLC-δ1 overexpression, and 75±9 in those with PLC-δ1 overexpression and PKC down-regulation (all p<0.05 among 3 groups). Ca2+ influx under treatment with nifedipine at 10-5M was 2.9±0.1 times higher in the cells with PLC-δ1 overexpression and 5.6±0.2 times higher in those with PLC-δ1 overexpression and PKC down-regulation compared with the control cells( all p<0.05 among 3 groups). Conclusions: ACh-induced Ca2+ influx was enhanced by PLC-δ1 overexpression, but was attenuated by PKC activation. PKC plays an important role in Ca2+ influx under enhanced PLC-δ1 in a negative feedback fashion.

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