Energy Metabolism And Physiological Function Of Artificial Hibernate Toad Research

It is important for understanding the low-temperature metabolism characteristics and the influence of physiological function in toads to study the cardiac activity, gastrocnemius muscle contractility, electrophysiological characteristics of the sciatic nerve and the variation of body macronutrients during hibernation. To investigate the effects of artificially induced hibernation on the change of physiological function amphibian and the consumption of macronutrients in the blood and tissue in Asiatic toads, Bufo gargarizans, the toads were induced to hibernation in the artificial condition for 56 days, and the body mass, organic index of heart, liver and gastrocnemius muscle, cardiac activity, gastrocnemius muscle contractility, electrophysiological characteristics of the sciatic nerve, as well as the concentrations of glucose, total protein and total cholesterol in blood, the contents of glycogen in the hepatic tissue and skeletal muscle, and protein in the skeletal muscle and myocardium were measured on the day before hibernation and the day of 1,3,7,14,28,42 and 56 post hibernation. Differences among groups in body mass and organic indixes were analysed by one-way analyses of variance (ANOVAs), and changes in the blood concentrations and the tissue contents of macronutrients were evaluated by one-way analyses of covariance (ANCOVAs), using body mass as covariates. Differences among groups were evaluated by LSD t-tests. Differences were considered to be signincant at a level of P< 0.05.Results show:1) Compared with control group, the heart rate of the toad decreased significantly (P<0.05) on day 56 in low temperature hibernation. Conduction velocity and absolute refractory period, sciatic nerve-trunk action potential threshold stimulation and the threshold of the gastrocnemius muscle stimulation did not change significantly during hibernation.2) Compared with the pre-hibernation, the body mass did not change significantly during hibernation, and there was not significant sexual difference. The organic indexes of the heart, liver and gastrocnemius muscle in male toads were significantly higher than those in female (P< 0.01), but both the male and female showed no significant change in organic indexes during hibernation.3) The blood glucose concentration decreased significantly after day 42 (P< 0.01), the concentration of total protein decreased significantly (P< 0.05) on day 56, but total cholesterol did not change significantly. The blood macronutrients did not show significant sexual difference.4) The hepatic glycogen decreased significantly after day 42 of hibernation (P< 0.01), and the muscular glycogen decreased significantly after day 1 (P< 0.05), but the protein contents in the skeletal muscle and myocardium did not show significant differences. The tissue macronutrients showed no significant sexual difference. The cardiac activity, gastrocnemius muscle contractility and the electrophysiological characteristics of the sciatic nerve in toads were no obvious change during artificially induced hibernation. Artificial hibernation leads to the substantial decrease of the metabolic level, and the energy reserves in toads could be able to maintain a relatively stable states of macronutrients in blood and tissues in 1 months.