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dc.contributor.authorRenshaw, GMC
dc.contributor.authorWise, G
dc.contributor.authorDodd, PR
dc.date.accessioned2017-10-23T04:15:19Z
dc.date.available2017-10-23T04:15:19Z
dc.date.issued2010
dc.date.modified2011-01-25T06:53:04Z
dc.identifier.issn1095-6433
dc.identifier.doi10.1016/j.cbpa.2009.10.039
dc.identifier.urihttp://hdl.handle.net/10072/35768
dc.description.abstractInteractions between coral reef topography, tide cycles, and photoperiod provided selection pressure for adaptive physiological changes in sheltered hypoxic niches to be exploited by specialized tropical reef fish. The epaulette shark Hemiscyllium ocellatum withstands cyclic hypoxia in its natural environment, many hours of experimental hypoxia, and anoxia for up to 5 h. It shows neuronal hypometabolism in response to 5% oxygen saturation. Northern-hemisphere hypoxia- and anoxia-tolerant vertebrates that over-winter under ice alter their inhibitory to excitatory neurotransmitter balance to forestall brain ATP depletion in the absence of oxidative phosphorylation. GABA immunochemistry, HPLC analysis and receptor binding studies in H. ocellatum cerebellum revealed a heterogeneous regional accumulation of neuronal GABA despite no change in its overall concentration, and a significant increase in GABAA receptor density without altered binding affinity. Increased GABAA receptor density would protect the cerebellum during reoxygenation when transmitter release resumes. While all hypoxia- and anoxia-tolerant teleosts examined to date respond to low oxygen levels by elevating brain GABA, the phylogenetically older epaulette shark did not, suggesting that it uses an alternative neuroprotective mechanism for energy conservation. This may reflect an inherent phylogenetic difference, or represent a novel ecophysiological adaptation to cyclic variations in the availability of oxygen.
dc.description.peerreviewedYes
dc.description.publicationstatusYes
dc.languageEnglish
dc.language.isoeng
dc.publisherElsevier
dc.publisher.placeUnited States
dc.relation.ispartofstudentpublicationN
dc.relation.ispartofpagefrom486
dc.relation.ispartofpageto492
dc.relation.ispartofissue4
dc.relation.ispartofjournalComparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology
dc.relation.ispartofvolume155
dc.rights.retentionY
dc.subject.fieldofresearchBiochemistry and cell biology
dc.subject.fieldofresearchZoology
dc.subject.fieldofresearchZoology not elsewhere classified
dc.subject.fieldofresearchcode3101
dc.subject.fieldofresearchcode3109
dc.subject.fieldofresearchcode310999
dc.titleEcophysiology of neuronal metabolism in transiently oxygen-depleted environments: Evidence that GABA is accumulated pre-synaptically in the cerebellum
dc.typeJournal article
dc.type.descriptionC1 - Articles
dc.type.codeC - Journal Articles
gro.date.issued2010
gro.hasfulltextNo Full Text
gro.griffith.authorRenshaw, Gillian M.
gro.griffith.authorWise, Graham
gro.griffith.authorDodd, Peter


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