The piglet as an animal model for hypobaric hypoxia.

The objective of this study was to evaluate the piglet as a suitable animal model for human diseases of high altitude. We studied 12 piglets, 4-10 weeks old, in a hypobaric chamber under conditions of high altitude at a pressure of 1/2 atmosphere (to approximately 320 Torr) for various periods of time (12, 24, 36, 48, and 72 hours) with continuous monitoring. The animals were decompressed every 24 hours for grooming and feeding.

Sites and ionic mechanisms of hypoxic vasoconstriction in frog skin.

We tested the hypothesis that the cellular mechanisms mediating hypoxic vasoconstriction (HVC) in frog skin, an important vertebrate respiratory organ, are similar to those mediating HVC in the pulmonary vasculature of mammals. An accepted hypothesis in the lung is that alveolar hypoxia alters the redox potential in vascular smooth muscle cells of arterial vessels. This decreases membrane K+ conductance, causing depolarization.

Thermoregulatory changes by hypoxia: lessons from the paramecium.

1. In organisms ranging from paramecia to mammals, hypoxia elicits a regulated decrease in body temperature (Tb). A decrease in Tb is an important adaptation to hypoxia primarily because it lowers metabolic rate when oxygen supply is limited, thus facilitating survival.

Hypoxia decreases opioid delta receptor expression in mouse brain.

Delta opioid receptor activation is protective during hypoxic injury. Many adaptive responses occur during exposure to hypoxia to facilitate survival. It is possible that increased activity of the delta opioid receptor system is one such adaptation.

Thermoregulatory effects of cyanide and azide in the toad, Bufo marinus.

An important adaptation to hypoxia is a regulated reduction in body temperature (Tb; anapyrexia), presumably because it lowers metabolic rate when oxygen supply is limited. Although this beneficial response occurs in organisms ranging from protozoans to mammals, little is known of the cellular mechanisms involved. We showed previously that inhibition of oxidative phosphorylation mediates hypoxia-induced anapyrexia in the paramecium.