Control of carbohydrate metabolism in an anoxia-tolerant nervous system.
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.
Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. lucianof@ufrgs.br
Luciano Stürmer
LS
de Fraga
Roselis Silveira Martins
RS
da Silva
Denise Maria
DM
Zancan
D000818:Animals; D002490:Central Nervous System / Q000201:enzymology / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism*; D024981:Glycogen Phosphorylase / Q000378:metabolism*; D006006:Glycogen Synthase / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D012908:Snails / Q000201:enzymology / Q000378:metabolism*
D006003:Glycogen; D024981:Glycogen Phosphorylase; D006006:Glycogen Synthase; D005947:Glucose