Effects of TEA on MIT in muscle strips from virgin nonpregnant (a), early pregnant (b), mid-pregnant (c) and late pregnant (d) myometrium. MIT is normalized to the activity observed during an initial 7.5 min control period. The white bars illustrate activity during two preceding control periods, and the black bars show the effects of subsequent cumulative addition of TEA (1, 5 and 10 mM) (n=6, 6, 9 and 8 for virgin, early, mid- and late pregnant strips, each from a different animal). *P<0.05; **P<0.001; ***P<0.001.