FIG. 5.

Intracellular Ca²⁺ signaling in two-dimensional-cultured articular chondrocytes stimulated with digoxin and ATP. (A) Representative images of chondrocytes cultured on glass slides showing an increase in intracellular Ca²⁺ upon induction with ATP at 15 min. (B) Representative Ca²⁺ traces induced by each agent. ATP and digoxin+ATP induced similar responses. Traces were shifted on the y-axis for better visualization. Downward drifts were due to photobleaching. (C) All agents increased the frequency of Ca²⁺ oscillations over baseline controls, as determined by a paired t-test (significance denoted by an asterisk). ATP and digoxin+ATP induced more Ca²⁺ oscillations than digoxin alone, as determined by a one-way analysis of variance comparing the different drugs (black bars). Significant differences (p<0.05) exist between groups not sharing the same letters. Color images available online at www.liebertpub.com/tea