Thank very much Dr. Grover. Even though its not as much fun as travelling to attend a conference, I am enjoying surfing through these very interesting works and ideas. Regarding your question, The culture smooth muscles cells (passage four), that we used in this study, were confirmed to retain their phenotypes according to the following criteria: a) the cells protein reacted with -actin smooth muscle antibodies in Western blots provide an -actin band (45kDa), and with SERCA2b selective antibodies give 115kDa bands, b) the cells retained the typical spindle shape of the smooth muscle cells, and c) all the cells reacted with -actin antibodies using immunohistochemical staining (A.B. Elmoselhi et al, 1995, Mol. Cell. Biochem., 151: 149-155)
Moreover, the possible alteration of the Ca2+ sensitive dye used (fluo-3) by peroxide was also eliminated, since peroxide concentration below 10 mM did not affect the fluorescence or binding characteristics of fluo-3 ( Sandhu V. el al, 1998, Mol. Cell. Biochem, 178 (1-2): 77-80).
Thus, the difference in peroxide sensitivity, as we suggested and it is consistent with others, is due to Ca2+-independent mechanism(s) that involved in ET-1 mediated contraction in coronary artery smooth muscle which appears to be resistence to peroxide damage.