Fig. 13.

Nuclear reactivity to caffeine is correlated with the presence of calciosomes. The time course of change in nuclear [Ca]_i was measured after application of 10 mmcaffeine. Experiments were conducted in young (A) and mature (B) cultures, and the cells were classified into three groups: cells containing no visible CCOs [group (gr.) 1], few CCOs (gr.2), and many CCOs (gr.3). In the older group, no organelle-free cells were found. In both age groups, a shorter latency to caffeine was seen in CCO-containing neurons. A smaller response was seen in CCO-free cells. C, Time course of appearance of CCOs. Cultures were stained with Fluo-3, and the proportion of cells containing these organelles was registered. (The total number of cells counted in each age group is depicted at the bottom of each column.)