Influence of acclimation and determination temperature on the oxygen consumption of the brain in two species of anurans

Abstract

1. 1. The effects of sudden changes by increasing or decreasing the measurement temperature on the oxygen consumption of the brains of Bufo arenarum and Leptodactylus ocellatus were determined. 2. 2. The experiments were carried at in vitro at temperatures which range from 4 to 37°C. The brain was oxygenated and stabilized for 20 min at each of the temperatures to which it was subjected before oxygen consumption measurements were made. 3. 3. A theoretical curve representing the variation of oxygen consumption with temperature was calculated according to the following exponential relationship; for Leptodactylus ocellatus y = 0.408 × 1.07 x and for Bufo arenarum y = 0.389 × 1.065 x . 4. 4. These results were compared with the brain oxygen consumption of animals acclimated to different temperatures, whose oxygen consumption was measured at a fixed temperature. Only Leptodactylus ocellatus had a significantly lower oxygen consumption in a high range of temperatures, indicating thermal compensation, probably to save metabolic reserves. 5. 5. No deterioration of the brain tissue was observed, as several passages from high to low temperatures in the range of 20°–30°C, showed a reversible oxygen consumption in acclimated and non-acclimated Bufo arenarum and Leptodactylus ocellatus.