Fig. 2

Influence of acetylcholine (ACh) on the tension (A) amplitude (B) and frequency (C) of the contraction of the porcine endometrium/myometrium (ENDO+MYO) and myometrium (MYO) strips collected on days 12–14 of the oestrous cycle (cyclic) or after first insemination) (groups without embryos and with embryos). Values (mean ± SD) represents five uterine horns examined in two strips from each one and are expressed as a percentage of changes in the contractile activity before the treatment. *P < 0.05, **P < 0.01, ***P < 0.001 as compared to the contractile activity before the treatment; a, b, c indicates differences between groups (cyclic, without embryos and with embryos)