Hypobaric hypoxia and hedonic matrix in rats.

This study was carried out to evaluate the effect of continuous exposure to hypobaric hypoxia on the feeding behavior and taste responses of rats, under simulated conditions of a high altitude (HA) of 7,620 m for 21 h a day and consecutively for 18 d, which more closely resembles actual field conditions. Their food, water intake and body weight were recorded daily, and blood sugar was estimated once a week. All the parameters were recorded for a period of 18 d each, before, during, and after exposure to simulated HA. The results show a decrease in daily food and water intake and body weight, and mild hypoglycemia during hypoxic exposure. Single-bottle and two-bottle tests showed a preference for sweet solutions over water, citric acid, sodium chloride, and quinine sulfate during exposure. The two-bottle test showed a preference for glucose over calorically-inert saccharine. The continuous exposure in this study produced qualitatively similar but quantitatively accentuated results as compared to intermittent 6 h exposure contiguously for 21 d. High-altitude stress appears to influence food intake such that sensory cues assume greater significance during feeding behavior.