Cold physiology: Postprandial blood flow dynamics and metabo

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TitleCold physiology: Postprandial blood flow dynamics and metabolism in the Antarctic fish Pagothenia borchgrevinkiAbstractPrevious studies on metabolic responses to feeding (i.e. the specific dynamic action, SDA) in Antarctic fishes living at temperatures below zero have reported long-lasting increases and small peak responses. We therefore hypothesized that the postprandial hyperemia also would be limited in the Antarctic fish Pagothenia borchgrevinki. The proportion of cardiac output directed to the splanchnic circulation in unfed fish was 18%, which is similar to temperate fish species. Contrary to our prediction, however, gastrointestinal blood flow had increased by 88% at twenty four hours after feeding due to a significant increase in cardiac output and a significant decrease in gastrointestinal vascular resistance. While gastric evacuation time appeared to be longer than in comparable temperate species, digestion had clearly commenced twenty four hours after feeding as judged by a reduction in mass of the administered feed. Even so, oxygen consumption did not increase suggesting an unusually slowly developing SDA. Adrenaline and angiotensin II was injected into unfed fish to investigate neuro-humoral control mechanisms of gastrointestinal blood flow. Both agonists increased gastrointestinal vascular resistance and arterial blood pressure, while systemic vascular resistance was largely unaffected. The hypertension was mainly due to increased cardiac output revealing that the heart and the gastrointestinal vasculature, but not the somatic vasculature, are important targets for these agonists. It is suggested that the apparently reduced SDA in P. borchgrevinki is due to a depressant effect of the low temperature on protein assimilation processes occurring outside of the gastrointestinal tract, while the gastrointestinal blood flow responses to feeding and vasoactive substances resemble those previously observed in temperate species. Â© 2012 Sandblom et al.

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1st AuthorSandblom, E. AuthorSandblom, E.Davison, W.Axelsson, M.Year2012JournalPLoS ONEVolume7Number3DOI10.1371/journal.pone.0033487URLhttps://www.scopus.com/inward/recor.....dbcf75cb9dd8c8d5b25aa99a0Keywordsadrenalinangiotensin IIadrenalinangiotensin II, animal experimentanimal foodarterial pressurearticlecardiopulmonary hemodynamicscold sensitivitycontrolled studydigestionfishfood intakegastrointestinal circulationgastrointestinal tractgastrointestinal vascular resistanceheart blood vesselheart outputhyperemiahypertensionintestine blood flowmetabolic regulationneuromodulationnonhumanoxygen consumptionPagothenia borchgrevinkipostprandial statesplanchnic blood flowstomach emptyingsystemic vascular resistancetarget organvascular resistanceadaptationanalysis of varianceanimalAntarcticablood flowblood pressurecoldcomparative studydrug effectheart ratePerciformesphysiologypostprandial statevascularization, Pagothenia borchgrevinkiPisces, Adaptation, BiologicalAnalysis of VarianceAngiotensin IIAnimalsAntarctic RegionsBlood PressureCardiac OutputCold TemperatureEpinephrineGastric EmptyingGastrointestinal TractHeart RateOxygen ConsumptionPerciformesPostprandial PeriodRegional Blood FlowVascular Resistance

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CitationSandblom, E., Davison, W. and Axelsson, M. (2012). Cold physiology: Postprandial blood flow dynamics and metabolism in the Antarctic fish Pagothenia borchgrevinki. PLoS ONE, 7(3)