Effects of protein kinase C activation on intracellular Ca2+ distribution in vascular smooth muscle cells of spontaneously hypertensive rats.
Protein kinase C is known to influence contraction in vascular smooth muscle cells by Ca(2+)-dependent and Ca(2+)-independent mechanisms. In the present study, the effect of protein kinase C activation by phorbol 12-myristate 13-acetate on resting cytosolic free Ca2+ and on cellular Ca2+ pools was assessed in cultured rat aortic muscle cells using fura 2. Cellular Ca2+ pools were evaluated with the selective inhibitor of the sarcoplasmic Ca2+ ATPase, thapsigargin. In normotensive vascular smooth muscle cells, protein kinase C activation caused a redistribution of Ca2+ from the thapsigargin-sensitive pool into the cytoplasm, whereas, in hypertensive cells, no significant effect of protein kinase C activity on cellular Ca2+ distribution was found. It is concluded that protein kinase C modulates the amount of Ca2+ stored in the thapsigargin-sensitive calcium stores. In hypertensive cells, the regulation of Ca2+ pools by protein kinase C is disturbed.
Medizinische Universitäts-Poliklinik, Münster, FRG.
M
M
Neusser
P
P
Golinski
Z
Z
Zhu
M
M
Tepel
W
W
Zidek
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004789:Enzyme Activation; D007425:Intracellular Membranes / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D009994:Osmolar Concentration; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D013729:Terpenes / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019284:Thapsigargin; D014018:Tissue Distribution
D013729:Terpenes; D019284:Thapsigargin; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium