Physioengineering approach to the autonomic nervous control of the heart rate fluctuations in developing embryos.

1.Daily changes(Developmental Patterns)of embryonic heart rate(HR)of the king quail(mean egg mass=about6g)were determined during the whole incubation period.Allometric@equation of HR in9species of the precocial birds including the king quail and ostrich was redulted in HR=440·M^&lt；-0.128&gt；(M=egg mass in g).2.Developmental patterns of embryonic HR in chickens were determined by impedancecardiogrpahy during the first half of incubation without impeding gas exchange through the eggshell.Additionally，the responses of embryonic HR to 10%O_2and 100%O_2exposoures were investigated.3.Embryonic HR of chickens was measured continously by acoustocardiography throughout the last half of incubation。In addition to the HR irregularities which began to appear on days 14-16，the HR variability(Cyclic Oscillation)with period of 0.5-1 hour was found to appear on these days and the magnitude of the oscillation became augmented with embryonic development.4.It was found that appearance and time course of respiratory movements due to lung ventilation of embryos prior to and during internal prior to and during internal pipping could be recorded by stouocy。This is the new finding which may contribute to an investigation of ontogenic mechanism of pulmonary gas exchange in avian embryos.5.Using the electrocardiography，we could record the HR fluctuations of chick embryos during internal and external pipping period.It was found that the HR variability and irregularities and their time course were particularly unique in external pipping embryos.6.Autonomic nervous controls of the HR fluctuations during the prenatal development of chick embyos were investigated by dosing intravenously the various autonomic drugs.It was found that the transient deceleration of HR was produced by parasympathetic nervous functions.But，the relation between sympathetic nervous functions and various patterns of HR accleration was not clear and need further investigation.

1.Daily changes (developmental patterns) of embryonic heart rate (HR) of the king quail (mean egg mass=about 6g) were determined during the whole incubation period. Allometric equation of HR in 9 species of the precocial birds including the king quail and ostrich was redulted in HR=440・M^<-0.128> (M=egg mass in g).2.Developmental patterns of embryonic HR in chickens were determined by impedancecardiogrpahy during the first half of incubation without impeding gas exchange through the eggshell. Additionally, the responses of embryonic HR to 10% O_2 and 100% O_2 exposoures were investigated.3.Embryonic HR of chickens was measured continously by acoustocardiography throughout the last half of incubation. In addition to the HR irregularities which began to appear on days 14-16, the HR variability (cyclic oscillation) with period of 0.5-1 hour was found to appear on these days and the magnitude of the oscillation became augmented with embryonic development.4.It was found that appearance and time course of respiratory movements due to lung ventilation of embryos prior to and during internal pipping could be recorded by acoustocardiography. This is the new finding which may contribute to an investigation of ontogenic mechanism of pulmonary gas exchange in avian embryos.5.Using the electrocardiography, we could record the HR fluctuations of chick embryos during internal and external pipping period. It was found that the HR variability and irregularities and their time course were particularly unique in external pipping embryos.6.Autonomic nervous controls of the HR fluctuations during the prenatal development of chick embyos were investigated by dosing intravenously the various autonomic drugs. It was found that the transient deceleration of HR was produced by parasympathetic nervous functions. But, the relation between sympathetic nervous functions and various patterns of HR accleration was not clear and need further investigation.