UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

The effects of respiratory and metabolic acidosis on the metabolic rate of anaesthetized, paralyzed, and artificially ventilated ground squirrels (Spermophilus lateralis) Bharma, Supriti


This study was designed to test the hypothesis that changes in arterial pH (pHa) reflecting proportional changes in arterial hydrogen ion concentration ([H+]a) effect a change in oxygen consumption (VO2) or metabolic rate (MR), in euthertnic golden mantled ground squirrels (Spermophilus lateralis). Of interest were the specific effects, either local or reflex, of changing arterial pH on metabolic rate . Therefore, it was imperative that experimentally produced changes in pHa did not cause any compensatory changes in ventilation, since this would indirectly alter metabolic rate due to changes in the cost of breathing . It was also important that any changes in metabolic rate produced by the experimental manipulations did not cause any change in body temperature (Tb), since this would secondarily cause further changes in metabolic rate . As a consequence, these experiments were conducted on anaesthetized, paralyzed, and artificially ventilated animals maintained at constant Tb. Three series of experiments were conducted, each of which altered pHa in a different fashion. In the first series of experiments, (Series I, n = 6) pHa was randomly made either alkalotic or acidotic by altering the frequency and/or volume of the respirator, to increase or decrease minute ventilation (VE), and consequently hyper- or hypo-ventilate the animals . The average pHa was varied from 7 .19 ± 0.03 Units in the acidotic range, to 7 .55 ± 0.02 Units in the alkalotic range with corresponding arterial partial pressures of CO 2 (Paco2) of 52.8 ± 3 Torr and 25.9 ± 2 Torr, respectively. In this series, VO2 showed a significant (p < 0.001) positive correlation with pHa (r = + 0.84), decreasing 0 .24 ml.min-1 for every 0 .1 Unit decrease in pHa. (a 21 .78% decrease in metabolic rate for a decrease of 0 .36 pHa Units or a 6 .04% decrease in metabolic rate for each 0.1 unit decrease in pHa). [More abstract follows]

Item Media

Item Citations and Data


For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.