Figure 4: Effects of musclin on contraction of arterial strip and intracellular calcium in A7r5 cells. Vasoconstriction was induced in a concentration-dependent manner by musclin (0.01–10 nmol/L) in the arterial strips isolated from normal Wistar rats. The closed square showed the results in calcium-rich buffer while the closed circle showed the results in calcium-free buffer (a). Changes in intracellular calcium were detected with fura-2 by using a fluorescence spectrofluorometer. The cells were placed in buffered physiological saline solution with 5 μM of fura-2-AM and incubated for 1 h. After recording the baseline value, musclin was added into the cuvette to detect the free intracellular calcium (b). All values are presented as mean ± SEM ( ). * , ** , and *** compared with the control group (musclin 0 nM).