Figure 6.

Effect of NKA on the Ca²⁺-induced contraction of the α-toxin permeabilized pregnant rat myometrium. After the permeabilization with 5000 units ml⁻¹ α-toxin, the pregnant rat myometrial strip was contracted by 0.5 μM Ca²⁺ in the presence of either 1 μM GTP (a) or 1 mM GDPβS (b). When the tension reached the steady state, 100 nM NKA was applied. After the application of NKA, GTPγS (10 μM) was added. Maximal tension was induced by 10 μM Ca²⁺. The developed tension was expressed as a percentage, assigning the values in the relaxing solution ([Ca²⁺]_i <10⁻⁸ M) and in the activating solution ([Ca²⁺]_i=10⁻⁵ M) to be 0 and 100% respectively.