Heart adrenoreactivity during acute haemic hypoxia

The influence of acute haemic hypoxia of mild and moderate degree, produced by subcutaneous administration of sodium nitrite (25-30 or 50 mg/kg) supporting the blood haemoglobin production, on heart adrenoreactivity was studied in experimental rats. An intensified sympathoadrenal activity was detected, that manifested itself by a marked increase in adrenaline content in the hypothalamus, brain stem and heart. In analogous experiments performed in dogs, with increasing severity of hypoxia a decrease in arterial pressure and left ventricular pressure, increase in left ventricular end-diastolic pressure, and an impairment of myocardial contractile function were observed. Administration of adrenergic substances intensified the effector reaction in the heart. According to the authors' conclusions, experimental, hypoxia of the given model calls forth intensification of heart adrenoreactivity in warm-blood animals.