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Accueil du site → Doctorat → Australie → Physiological adjustments to aestivation and activity in the cocoon-forming frogs Cyclorana platycephala and Cyclorana maini

University of Western Australia (2008)

Physiological adjustments to aestivation and activity in the cocoon-forming frogs Cyclorana platycephala and Cyclorana maini

Word, James Mabry

Titre : Physiological adjustments to aestivation and activity in the cocoon-forming frogs Cyclorana platycephala and Cyclorana maini

Auteur : Word, James Mabry

Université de soutenance : University of Western Australia

Grade : Doctor of Philosophy PhD 2008

Résumé
The desert-adapted frogs Cyclorana platycephala and Cyclorana maini survive long periods of inhospitably hot and dry conditions by retreating underground and aestivating. While aestivating they suspend food and water intake as well as physical activity, depress their metabolic rate by 80 %, and form cocoons that protect them against desiccation. How these frogs function during this exceptional state is largely unknown. This work characterized a number of physiological parameters in three metabolic states spanning their natural metabolic range : during aestivation (depressed metabolism), at rest (normal metabolism), and where possible, during exercise (elevated metabolism). The primary objective was to identify by comparison, physiological adjustments in these parameters to metabolic depression, as well as the scope of these parameters in frogs capable of aestivation. The parameters measured for C. maini were (a) the glucose transport kinetics and (b) the fluid balance of an extensive number of their individual organs. For C. platycephala, the parameters measured were (a) the activity of the cardiovascular system as indicated by heart rate and blood pressure and (b) the roles of pulmonary and cutaneous respiratory systems in gas exchange

Subject words : Estivation • Respiration physiology • Cardiovascular physiology • Amphibia • Glucose metabolism • Metabolic depression

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Page publiée le 6 mars 2009, mise à jour le 16 juillet 2017