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Table 2 Changes in the uterus-contracting effect of (−)-noradrenaline (EC50 and Emax values) in the absence of α2-antagonists (a), or in the presence of an α2A-antagonist (b), an α2B/C-antagonist (c), an α2C-antagonist (d) or an α2A- and an α2C-antagonists (e) in the 22-day-pregnant rat without and after progesterone pretreatment

From: The effects of progesterone on the alpha2-adrenergic receptor subtypes in late-pregnant uterine contractions in vitro

 

EC50 (M ± S.E.M.)

Emax (% ± S.E.M)

(a) CONTROL

 Non-treated

2.6×10−6 ± 1.2×10−6

274.1 ± 47.1

 Progesterone-pretreated

1.7×10−6 ± 7.8×10−7 ns

94.0 ± 14.4 **

(b) BRL 44408

 Non-treated

1.8×10−6 ± 6.4×10−6

364.3 ± 70.8

 Progesterone-pretreated

1.2×10−5 ± 4.8 ×10−6 ns

57.4 ± 12.9 ***

(c) ARC 239

 Non-treated

1.2×10−6 ± 1.1×10−6

147.1 ± 79.4

 Progesterone-pretreated

5.3×10−6 ± 1.5×10−6 ns

83.7 ± 22.1*

(d) SPIROXATRINE

 Non-treated

1.6×10−6 ± 5.4×10−6

382.4 ± 93.5

 Progesterone-pretreated

5.9×10−6 ± 1.4×10−6 ns

41.0 ± 15.2 ***

(e) BRL 44408 + SPIROXATRINE

 Non-treated

2.9×10−6 ± 8.4×10−7

444.6 ± 51.3

 Progesterone-pretreated

2.8×10−6 ± 2.7 ×10−5 ns

102.9 ± 32.62 ***

  1. EC50: the concentration of (−)-noradrenaline alone or in the presence of an α2-AR antagonist which elicits half of the maximum contracting effect of (−)-noradrenaline. Emax: the maximum contracting effect of (−)-noradrenaline alone or in the presence of an α2-AR antagonist. Significance levels were calculated in comparison with non-treated values. ns: not significant; *: p < 0.05; **: p < 0.01; ***: p < 0.001