Table 2

Reversal by Bay K 8644 of nifedipine and genistein inhibition of myometrial contraction

Bombesin
0.5 nM2.5 nM
% of maximal contractile response
Control21  ± 275  ± 7
Nifedipine (10 nM)5  ± 0.52-a 32  ± 32-a
Genistein (20 μM)2  ± 0.22-b 27  ± 42-b
Bay K 8644 (10 nM)ND83  ± 9
Bay K 8644 (10 nM) + nifedipine (10 nM)18  ± 32-c 68  ± 72-c
Bay K 8644 (10 nM) + genistein (20 μM)16  ± 22-d 70  ± 82-d

Isometric contractions were integrated during 2-min exposure of loaded myometrial segments to the indicated concentrations of bombesin before or after the addition of genistein (20 μM) or nifedipine (10 nM) for 10 min and 4 min, respectively. When used, Bay K 8644 (10 nM) was added 1 min before genistein or nifedipine. The degree of contraction is expressed as a percentage of the response elicited by the maximal concentration of bombesin. Values are mean ± S.E.M. for three independent experiments.

  • ND, not determined.

  • ↵2-a P < .01 nifedipine + bombesin versus bombesin alone.

  • ↵2-b P < .01 genistein + bombesin versus bombesin alone.

  • ↵2-c P < .01 Bay K 8644 + nifedipine + bombesin versus nifedipine + bombesin.

  • ↵2-d P < .01 Bay K 8644 + genistein + bombesin versus genistein + bombesin.