Fig. 2. Ropivacaine (Rop)–induced, dose-dependent, biphasic increase in intracellular calcium concentration ([Ca2+]i) of rat aortic smooth muscle. The [Ca2+]iof fura-2–loaded aortic strips was detected using fluorometer and was expressed as the ratio F340/F380 ( A ). The [Ca2+]ilevels stimulated by ropivacaine are presented as a percent of the 30 mm potassium chloride (KCl)–induced value ( B ). * P < 0.05, ** P < 0.01 versus baseline (n = 6).