ADENOSINE, A RETALIATORY METABOLITE, PROMOTES ANOXIA TOLERANCE IN TURTLE BRAIN

Citation
Ma. Perezpinzon et al., ADENOSINE, A RETALIATORY METABOLITE, PROMOTES ANOXIA TOLERANCE IN TURTLE BRAIN, Journal of cerebral blood flow and metabolism, 13(4), 1993, pp. 728-732
Citations number
48
Language
INGLESE
art.tipo
Note
Categorie Soggetti
Neurosciences,"Endocrynology & Metabolism",Hematology
ISSN journal
0271-678X
Volume
13
Issue
4
Year of publication
1993
Pages
728 - 732
Database
ISI
SICI code
0271-678X(1993)13:4<728:AARMPA>2.0.ZU;2-Z
Abstract
Contrary to what is found in most vertebrates, the brains of certain t urtle species maintain ATP levels and ion homeostasis and survive prol onged anoxia. The hypothesis tested here is that the release of adenos ine and its binding to A1 receptors are essential for this anoxic tole rance. Studies were conducted in the isolated turtle cerebellum, which did release adenosine to the extracellular space during anoxia. When adenosine receptor antagonists [theophylline, 8-cyclopentyltheophyllin e (CPT), or 8-cyclopentyl-1,3-dipropylxanthine (DPCPX)] were added to the superfusate under control conditions, they had no effect on extrac ellular potassium ion activity ([K+]o). During anoxia, however, these antagonists provoked maximal efflux of K+ (anoxic depolarization). Ano xic depolarization occurred earlier during anoxia with theophylline (a nonspecific adenosine receptor antagonist) than with CPT or DPCPX, wh ich specifically block A1 receptors. Therefore, adenosine release and effects mediated by A1 receptors are essential to anoxia tolerance in turtle brain.