Experimental design for measurement of myometrial contractions. Test substances were added to the organ bath when myometrium strips had been contracting regularly for 30 min. When the effects of BPJ and/or atosiban were being studied ( a ) , Krebs solution (control), BPJ, atosiban, or the combination of BPJ and atosiban were added, and contractility was recorded for 30 min. When the effects of BPJ and/or nifedipine were being studied ( b ) , Krebs solution (control; two strips) or nifedipine (two strips) was added, contractility was recorded for 30 min, and then BPJ was added to all chambers. Exposure to test substances was followed by a 30 min washout step, with change of Krebs solution at 5, 10, 20 and 30 min
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