Excessive dopamine (DA) is known to cause hypoxic/ischemic damage to mammalian brain. The freshwater turtle Trachemys scripta, however, maintains basal striatal DA levels in anoxia. We investigated DA balance during early anoxia when energy status in the turtle brain is compromised. The roles of ATP-sensitive potassium (K(ATP)) channels and adenosine (AD) receptors were investigated as these fa...

For most vertebrates, cutting off the oxygen supply to the brain results in a rapid (within minutes) loss of ATP, the failure of ATP-dependent ion-transport process, subsequent anoxic depolarization of neuronal membrane potential and consequential neuronal death. The few species that survive brain anoxia for days or months, such as the freshwater turtle Trachemys scripta, avoid anoxic depolariz...

The effects of sustained anoxia on cardiac electrical excitability were examined in the anoxia-tolerant crucian carp (Carassius carassius). The electrocardiogram (ECG) and expression of excitation-contraction coupling genes were studied in fish acclimatised to normoxia in summer (+18°C) or winter (+2°C), and in winter fish after 1, 3 and 6 weeks of anoxia. Anoxia induced a sustained bradycardia...

Resting heat rate was measured in superfused rabbit papillary muscles at 20 degrees C during 40 minutes of anoxia and subsequent reoxygenation. To reveal the nature of the reactions underlying energy output under such conditions, the data obtained were compared with values predicted from data on chemical change. Before and after the anoxic period, muscles were stimulated at 0.2 Hz, during which...

In the developing heart, cardiomyocytes undergo terminal differentiation during a critical window around birth. Hypoxia is a major stress to preterm infants, yet its effect on the development and maturation of the heart remains unknown. We tested the hypothesis in a rat model that newborn anoxia accelerates cardiomyocyte terminal differentiation and results in reduced cardiomyocyte endowment in...