Fig. 3. Menadione-induced cytosolic Ca²⁺ moves quickly into the nucleus. The upper part of the figure shows transmitted light pictures of experimental cells (a-d). Positions of nuclei (bright spots) are clearly visible on fluorescence pictures of cells (e-h). Linescans (i-l) of fluorescent intensity of Fura Red in pancreatic acinar cells along the line connecting secretory granule region (initiation site of Ca²⁺ response) and nucleus after 25 nM ACh (i), 100 nM ACh (j), 20 µM menadione (k) and after addition of 100 nM ACh together with 100 nM antimycin A (l) are shown. The lower section of the figure (m-p) shows schematic representation of the results: in physiological conditions 25 nM ACh application induce a Ca²⁺ spike that does not enter the nucleus (m). Higher doses of ACh (100 nM) induce a large Ca²⁺ wave that is substantially delayed on its way to the nucleus (n). Menadione (o) and ACh together with antimycin A (p) induce Ca²⁺ waves that propagate uniformly. Angles ß and represent speeds of Ca²⁺ waves (nuclear speed ß in comparison to speed in non-nuclear region). Lower part (q) shows average values of ratio of Ca²⁺ speed propagation (nuclear speed ß by non-nuclear ) induced by ACh, menadione or ACh with antimycin A.