MODULATION OF BRADYKININ-INDUCED INTRACELLULAR CA2-KI-RAS-TRANSFORMEDFIBROBLASTS( OSCILLATIONS IN V)

Modulation of bradykinin (BK)induced intracellular Ca2+ oscillations w as investigated with single cell Ca2+ anlysis in v-Ki-ras-transformed NIH3T3 fibroblasts. The Ca2+ oscillations were inhibited. by the addit ion of a specific antagonist for subtype 2 of BK receptors (B-2 recept or), not the antagonist for B-1 receptor. Decrease of the extracellula r Ca2+ concentration suppressed tide [Ca2+](i) oscillations and applic ation of thapsigargin dissipated the [Ca2+](i) oscillations. These fin dings suggest that the continuous activation of B-2 receptor leading t o the fluctuations of both Ca2+ influx which refills the internal Ca2 stores 1 and Ca2+ mobilization from the internal stores, is essential to the occurrence of the [Ca2+](i) oscillations in these cells.