if a ca2+ ionophore , ionomycin ( 5 microm ) , was then added , [ ca2+ ] i rose to greater than 1 x 10 ( -6 ) m , microtubules fragmented and depolymerized , and cell contraction and rounding very similar to that induced by h2o2 occurred .
C0026046
microtubules
C0007634
cell