Fig. 7. Low concentrations of ET augment nuclear CaTs in the absence of increases in cytoplasmic CaTs. (A) Original recording of cytoplasmic (black) and nuclear (red) CaTs of an atrial myocyte before and during exposure to 0.1 nM ET. (B) Changes of peak systolic [Ca²⁺] in the cytoplasm (left) and nucleus (right) induced by 0.1 nM ET. (C) Normalised ratio of nuclear to cytoplasmic [Ca²⁺] following application of 0.1 nM ET. In B and C, values are normalised to the initial control (=100%). Means ± s.e.m. of six atrial myocytes (N.S.=not significant).