Control of carbohydrate metabolism in an anoxia‐tolerant nervous system

Abstract

Anoxia-tolerant animal models are crucial to understand protective mechanisms during low oxygen excursions. As glycogen is the main fermentable fuel supporting energy production during oxygen tension reduction, understanding glycogen metabolism can provide important insights about processes involved in anoxia survival. In this report we studied carbohydrate metabolism regulation in the central nervous system (CNS) of an anoxia-tolerant land snail during experimental anoxia exposure and subsequent reoxygenation. Glucose uptake, glycogen synthesis from glucose, and the key enzymes of glycogen metabolism, glycogen synthase (GS) and glycogen phosphorylase (GP), were analyzed. When exposed to anoxia, the nervous ganglia of the snail achieved a sustained glucose uptake and glycogen synthesis levels, which seems important to maintain neural homeostasis. However, the activities of GS and GP were reduced, indicating a possible metabolic depression in the CNS. During the aerobic recovery period, the enzyme activities returned to basal values. The possible strategies used by Megalobulimus abbreviatus CNS to survive anoxia are discussed.

Effects of sciatic nerve transection on glucose uptake in the presence and absence of lactate in the frog dorsal root ganglia and spinal cord

“…The pH was adjusted to 7.4 (Kaloyianni and Doukakis, 2003). Glucose was not added to guarantee the availability of glucose transporter as done in other studies (Machado et al, 1991;Kaloyianni and Doukakis, 2003;Fraga et al, 2010). Each ganglion was placed in chilled Eppendorf tubes with known weight, and weighed again.…”

Occurrence of Cruzia tentaculata Larvae in the Land Snail Megalobulimus abbreviatus—Influence of Natural Parasite Load on Snail Physiology

“…To answer these questions, the present study analyzes snails of the species Megalobulimus abbreviatus Bequaert, 1948, collected from southern Brazil, naturally infected by nematode larvae. Concerning the possible effects of this interaction on the health of the host, which has been used as an experimental model in neurophysiological studies (Achaval et al, 2005; De Fraga et al, 2010; Martinez-Pereira et al, 2017), this study aimed to identify the species of nematode found in M. abbreviatus and to evaluate the general health conditions of the snails in relation to parasite load. The relationships between parasite load and intermediary metabolism, ovotestis and albumen gland measurements and structural changes to the intestinal tract resulting from the presence of encapsulated larvae, were analyzed.…”