title: [Effect of hypoxia on amnion rhythmic contractions and heart rate in the embryonic European pond turtle Emys orbicularis (Reptilia: Emydidae)].
abstract: The effect of acute hypoxia (10% O2 for 30 min) on the rate of amnion rhythmic contractions and heart rate (HR) was studied in two age groups of European pond turtle (Emys orbicularis) embryos, on days 19-27 and 37-43 of incubation (30-40 and 60-70% of the period until hatching). Under the control conditions, the two age groups of embryos did not differ from each other in either parameter. Hypoxia did not affect significantly the amnion contraction rate but decreased the HR. The time course of the HR during hypoxia depended on the embryo age. The mean HR in the first group of embryos was 8% decreased by minutes 10-14 of hypoxia and did not change afterwards; in the second group, it was 18% decreased by minutes 3-8 and then partly or completely restored before the end of hypoxic exposure. It has been assumed that the capacity of European pond turtle embryos for restoring the normal HR when exposed to acute hypoxia during the second half of embryogenesis is related to the development of neurohumoral control mechanisms.
authors.forename: M V
authors.initials: MV
authors.lastname: Nechaeva
authors.forename: I G
authors.initials: IG
authors.lastname: Vladimirova
mesh_terms: D000650:Amnion / Q000196:embryology / Q000502:physiology*; D000818:Animals; D004625:Embryo, Nonmammalian / Q000502:physiology; D005260:Female; D005311:Fetal Hypoxia / Q000196:embryology / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D014426:Turtles / Q000196:embryology / Q000502:physiology*