Combined ventilatory responses to aerial hypoxia and temperature in the South American lungfish Lepidosiren paradoxa

摘要: The control of pulmonary ventilation in South American lungfish Lepidosiren paradoxa is poorly understood. Interactions between temperature and hypoxia are particularly relevant due to large seasonal variations its habitat. Therefore, we tested the hypothesis that ventilatory responses aerial highly dependent on ambient temperature. We used a pneumotachograph measure (VE), tidal volume (VT) respiratory frequency (fR) during normoxic (21% O2) hypoxic (12%, 10% 7% conditions at two temperatures (25 35 °C). Blood gases, arterial PO2 (PaO2), PCO2 (PaCO2) pH (pHa) were also evaluated. At 25 °C, VE increased significantly levels when compared value O2). 35 °C, all elicited significant increase relative values. augmented mostly by increases (fR), there interactions (p<0.001) PaCO2 from ∼22 mmHg (normoxic 25 °C) ∼32 mmHg Concomitantly, pHa decreased 7.51 (25 °C) 7.38 (35 °C). Hypoxia-induced hyperventilation caused reduction an pHa, which more pronounced 35 °C than reflecting under high In conclusion, magnitude response temperature-dependent L. paradoxa, important for animal experiencing variations.