title: Inotropic effect of increasing concentration of Ca2+ in the fetal rat heart with retinoic acid-induced malformations.
abstract: Cardiac malformations (pulmonary trunk stenosis, ventricular septal defect, and double outlet right ventricle) were induced by the administration of two doses of retinoic acid (RA) to Wistar rats on d 13 of pregnancy. Contractile performance of the isolated perfused rat heart and its inotropic response to Ca2+ (0.6-10.0 mmol.L-1) was studied in 20-d-old fetuses. The body weight of RA-exposed fetuses was significantly lower compared with controls. RA negatively influenced the contractile parameters of the fetal rat heart. The most pronounced effect was, except at a Ca2+ concentration of 2.5 mmol.L-1, observed at developed force at all other concentrations. Simultaneously, the sensitivity to Ca2+, expressed as the Ca2+ concentration at which 30% of maximum was attained, ws significantly lower in RA-exposed hearts. This implies that the malformed heart is more dependent on the extracellular sources of Ca2+.
authors.affiliation: Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: I
authors.initials: I
authors.lastname: Ostádalová
authors.forename: T
authors.initials: T
authors.lastname: Pexieder
authors.forename: B
authors.initials: B
authors.lastname: Ostádal
authors.forename: F
authors.initials: F
authors.lastname: Kolár
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D005260:Female; D005318:Fetal Heart / Q000002:abnormalities / Q000187:drug effects* / Q000378:metabolism; D009200:Myocardial Contraction / Q000187:drug effects*; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D013268:Stimulation, Chemical; D014212:Tretinoin
chemical_list: D014212:Tretinoin; D002118:Calcium