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dc.contributor.authorRenshaw, Gillian
dc.contributor.authorB. Kerrisk, Christopher
dc.contributor.authorE. Nilsson, Goran
dc.contributor.editorThomas P. Mommsen, Patrick J. Walsh
dc.description.abstractThe epaulette shark (Hemiscyllium ocellatum) is among the few vertebrates that can tolerate extreme hypoxia for prolonged periods and, as shown here, anoxia. We examined how anoxia affected this shark's level of responsiveness, concentration of brain ATP and adenosine, an endogenous neuronal depressant. In addition, we investigated how these variables were affected by aminophylline, an adenosine receptor antagonist. Epaulette sharks placed in an anoxic environment (<0.02 mg O2 l -1) lost their righting reflex after 46.3Ხ8 min, but immediately regained vigilance upon return to normoxia. Then 24 h later, the same sharks were injected with either saline or aminophylline (30 mg kg-1) in saline and re-exposed to anoxia. In this second anoxic episode, controls sharks showed a 56% decrease in the time taken to lose their righting reflex but maintained their brain ATP levels; conversely, aminophylline-treated epaulette sharks displayed a 46% increase in the time to loss of righting reflex and had significantly lower brain ATP levels. Since anoxia also caused a 3.5-fold increase in brain adenosine levels, these results suggest that adenosine receptor activation had a pre-emptive role in maintaining brain ATP levels during anoxia. Perhaps because adenosine receptor activation initiates metabolic depression, indicated by the early loss of responsiveness (righting reflex), such a mechanism would serve to reduce ATP consumption and maintain brain ATP levels.en_US
dc.publisher.placeNew Yorken_US
dc.relation.ispartofjournalComparative Biochemistry and Physiology Part Ben_US
dc.subject.fieldofresearchHISTORY AND ARCHAEOLOGYen_US
dc.titleThe role of adenosine in the anoxic survival of the epaulette shark, Hemiscyllium ocellatumen_US
dc.typeJournal articleen_US
dc.type.descriptionC1 - Peer Reviewed (HERDC)en_US
dc.type.codeC - Journal Articlesen_US
gro.hasfulltextNo Full Text

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