Effects of ergometrine on airway smooth muscle contractile responses.
A 26-year-old asthmatic female developed severe asthma within a few hours of receiving three oral doses of 0.4 mg ergometrine maleate for the control of postpartum haemorrhaging. This experience and two previous reports of bronchospasm in asthmatic subjects following ergometrine suggested that ergometrine altered airway smooth muscle tone. In the present investigation the effect of ergometrine was studied on canine tracheal smooth muscle strips. Ergometrine (10(-9) M-10(-4) M) induced contraction of canine tracheal smooth muscle. The concentration causing 50% of maximal contraction (EC50) was 4.73 X 10(-8) M. The acetylcholine EC50 was not altered by ergometrine (10(-9) M or 10(-8) M); however, acetylcholine (10(-4) M and 10(-3) M) induced contractions were enhanced by ergometrine (10(-8) M). The data suggest that ergometrine maleate may cause broncho-constriction in some patients with asthma.
D000109:Acetylcholine / Q000494:pharmacology; D000328:Adult; D000818:Animals; D001249:Asthma / Q000209:etiology; D001986:Bronchial Spasm / Q000139:chemically induced; D004285:Dogs; D004874:Ergonovine / Q000009:adverse effects / Q000494:pharmacology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D011247:Pregnancy; D012137:Respiratory System / Q000187:drug effects*; D014132:Trachea / Q000187:drug effects
D000109:Acetylcholine; D004874:Ergonovine