Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10768555 | Biochemical and Biophysical Research Communications | 2005 | 7 Pages |
Abstract
The stimulation of the α1-adrenergic receptor with phenylephrine results in the significant extrusion of Mg2+ from the rat heart and cardiomyocytes. Phenylephrine-induced Mg2+ extrusion is prevented by the removal of extracellular Ca2+ or by the presence of Ca2+-channel blockers such as verapamil, nifedipine, or (+)BAY-K8644. Mg2+ extrusion is almost completely inhibited by PD98059 (a MAP kinase inhibitor). The simultaneous addition of 5 mM Ca2+ and phenylephrine increases the extrusion of Mg2+ from perfused hearts and cardiomyocytes. This Mg2+ extrusion is inhibited by more than 90% when the hearts are preincubated with PD98059. ERKs are activated by perfusion with either phenylephrine or 5 mM Ca2+. This ERK activation is inhibited by PD98059. Overall, these results suggest that stimulating the cardiac α1-adrenergic receptor by phenylephrine causes the extrusion of Mg2+ via the Ca2+-activated, Na+-dependent transport pathway, and the ERKs assists in Mg2+ transport in the heart.
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Authors
Shang-Jin Kim, Hyung-Sub Kang, Myung-Suk Kang, Xianfeng Yu, Sang-Yeol Park, In-Shik Kim, Nam-Soo Kim, Sung-Zoo Kim, Yong-Geun Kwak, Jin-Shang Kim,