Figure 5.

The effects of 100 nM NKA on the changes in [Ca²⁺]_i and tension induced by the cumulative application of external Ca²⁺ to Ca²⁺-free 40K⁺ solution in the pregnant rat myometrium. (a and b) Representative recordings of changes in [Ca²⁺]_i and tension induced by the cumulative application of external Ca²⁺ in Ca²⁺-free 40 mM K⁺ solution in the absence (a) or presence (b) of NKA in the pregnant rat myometrium. External Ca²⁺ (0.0125–5 mM) were applied cumulatively to Ca²⁺-free, 40 mM K⁺ solution in the absence (a : control) or presence (b) of 100 nM NKA. (b) NKA was applied 2 min before and during the cumulative application of extracellular Ca²⁺, and PPAD was applied 10 min before and during the application of NKA. The numbers with arrow heads on the traces represent the final extracellular Ca²⁺ concentrations. (c) [Ca²⁺]_i-tension relationship in the presence or absence of 100 nM NKA. The data points were obtained from the measurements using the protocol shown in a and b. The data are expressed as the mean±s.e.mean. (n=6).