Pharmacological characterization of mare uterus motility with special reference to calcium antagonists and beta-2-adrenergic stimulants.
1. Uterine motility was studied in vitro in the myometrial tissue obtained from pregnant and non-pregnant mares. 2. The spontaneous contractions of the preparations were not modified by tetrodotoxin, by anticholinergics, antiadrenergics, histamine H1 and H2 blockers, antiserotoninergic and opioid antagonists; but disappeared in Ca2+ and Na+ free medium. 3. beta 2-adrenergic stimulants like salbutamol and hexoprenaline and the calcium channel blockers nifedipine and verapamil were effective inhibitors of the amplitude of phasic contractions (ID50S for salbutamol and nifedipine were 7.7 nM and 14.6 nM, respectively in oestrus preparations). 4. The above data indicated that the mare myometrium contractility in vitro is very sensitive to the action of beta 2 mimetic compounds and calcium antagonists; nifedipine, in particular, seems to be a very promising alternative to beta 2 stimulants in the tocolytic therapy.
Coruzzi
G
G
Institute of Pharmacology, Faculty of Medicine, University of Parma, Italy.
Poli
E
E
Montanari
C
C
Bertaccini
G
G
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000420:Albuterol / Q000494:pharmacology; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D003470:Culture Media; D000242:Cyclic AMP / Q000378:metabolism; D004110:Diltiazem / Q000494:pharmacology; D005260:Female; D006594:Hexoprenaline / Q000494:pharmacology; D006736:Horses; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D009215:Myometrium / Q000187:drug effects; D009543:Nifedipine / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014590:Uterine Contraction / Q000187:drug effects*; D014700:Verapamil / Q000494:pharmacology
D000318:Adrenergic beta-Agonists; D002121:Calcium Channel Blockers; D003470:Culture Media; D013779:Tetrodotoxin; D014700:Verapamil; D000242:Cyclic AMP; D004110:Diltiazem; D006594:Hexoprenaline; D009543:Nifedipine; D000420:Albuterol; D007213:Indomethacin