Arousal and Re-Feeding

After aestivation, it is very important for Cyclorana to be able to feed as soon as possible. One would think that many months of disuse would have significant and detrimental effects to the digestive and muscular systems. However, Cylcorana handle the transition from dormancy to activity with surprising ease (Cramp and Franklin, 2008).

As discussed in Effects to Digestive System, digestive organs are significantly diminished after aestivation. Some individuals of Cyclorana may have only a few days to restore fuel supplies before having to aestivate again; therefore, they need to be able to digest food immediately upon resurfacing. One study showed that in individuals awaking from aestivation, the masses and lengths of the small and large intestines were the same as in control fed individuals only thirty-six hours after their first feeding. The small intestine itself increases by over 450% within those thirty-six hours (Cramp and Franklin, 2008).

It is apparent that metabolic rate, and potentially protein synthesis, is up-regulated upon arousal. While there is no data that suggests an up-regulation of protein synthesis in Cyclorana after aestivation (Cramp and Franklin, 2008), there is evidence that this occurs in squirrels after hibernation (van Breukelen and Martin, 2001). The length and shape of microvilli are related to the rates of protein synthesis. Since there is an increase in the production of microvilli upon arousal, there very likely is an up-regulation in protein synthesis. Also noted in Effects to Digestive System, enterocyte numbers decline during aestivation. Rapid proliferation of enterocytes and an increase in cell turnover also help organ masses by increasing villus height (Cramp and Franklin, 2008).

Upon arousal, the fat reserves in Cyclorana begin to decline, suggesting that fat reserves are necessary to fuel the processes of up-regulation. This helps explain why Cyclorana hold onto their reserves even during long periods of aestivation when they appear to be starving (Cramp and Franklin, 2008).

The ability of Cyclorana to avoid muscle atrophy is surprising, but their ability to emerge from aestivation with a working locomotor system if just as surprising. Cyclorana need to be able to hunt and mate whenever the opportunity arises, so it is vital that locomotion is not diminished by aestivation. Metabolic depression delays "the need to mobilize muscle protein and...reduc[es] the reactive oxygen species (ROS) insult from muscle mitochondria" (Lavidis and Hudson, 2008). Along with an up-regulation of antioxidants, these adaptations potentially prevent muscle disuse atrophy. Current research suggests that neurotransmitter release is reduced during aestivation and is increased upon arousal (2008). It is suspected that neurotransmitters are available during aestivation, but they are not released due to Cyclorana's calcium relationship. It is unsure whether there is a decrease in calcium entry or a decrease in calcium sensitivity, one study showed that the neuromuscular junctions (NMJs) of aestivating Cyclorana can be persuaded to act like those of control individuals by altering the calcium system (Lavidis and Hudson, 2008).