Fig. 2 a–h.

The effect of the long-term, 96-h serum deprivation on 2MeSADP-evoked calcium signals. The glioma C6 cells growing in the medium supplemented with 10% newborn calf serum (control cells) and those cultivated without serum for 96 h were loaded with Fura-2 and treated with 30 μM 2MeSADP or 10 μM ADP, as indicated by arrows. a, b, e, f Experiments performed in the standard buffer containing 2 mM CaCl₂. c, d, g, h Experiments conducted in the absence of extracellular Ca²⁺. Each trace represents the mean ratio value of the responses of the indicated number of cells (n), recorded in five separate experiments. a Black line Control cells induced by 2MeSADP, n = 71; gray line 96-h starved cells, n = 79. b Ca²⁺ responses in 96-h serum-deprived cells induced by 2MeSADP, n = 79, divided into groups according to the extent of response (light gray: cells with strong response, medium gray: cells with medium response, dark gray: cells with weak response). Black line Mean ratio value. c Control cells induced by 2MeSADP, n = 51. d 96-h starved cells induced by 2MeSADP, n = 49. e Black line Control cells induced by ADP, n = 51; gray line 96-h starved cells, n = 134. f Ca²⁺ responses in 96-h serum-deprived cells induced by ADP, n = 134, divided into groups according to the extent of response (light gray cells with strong response, medium gray cells with medium response, dark gray cells with weak response). Black line Mean ratio value. g Control cells induced by ADP, n = 97. h 96-h starved cells induced by ADP, n = 235. ***P < 0.001