3 documents found, page 1 of 1
Regulation of gill transcellular permeability and renal function during acute h...
Wood, Chris M.; Iftikar, Fathima I.; Scott, Graham R.; Boeck, Gudrun de; Sloman, Katherine A.; Matey, Victoria E.; Domingos, Fabíola Xochilt ValdezEarlier studies demonstrated that oscars, endemic to ion-poor Amazonian waters, are extremely hypoxia tolerant, and exhibit a marked reduction in active unidirectional Na+ uptake rate (measured directly) but unchanged net Na+ balance during acute exposure to low Po2, indicating a comparable reduction in whole body Na+ efflux rate. However, branchial O2 transfer factor does not fall. The present study focused on...
Tribute to R. G. Boutilier: The effect of size on the physiological and behavio...
Sloman, Katherine A.; Wood, Chris M.; Scott, Graham R.; Wood, Sylvia; Kajimura, Makiko; Johannsson, Ora E.; Almeida-Val, Vera Maria FonsecaThe physiological and behavioural responses of two size groups of oscar (Astronotus ocellatus) to hypoxia were studied. The physiological responses were tested by measuring ṀO2 during decreasing environmental oxygen tensions. Larger oscars were better able to maintain oxygen consumption during a decrease in PO2, regulating routine ṀO2 to a significantly lower PO2 threshold (50 mmHg) than smaller oscars (70 mmHg...
Interactions between hypoxia tolerance and food deprivation in Amazonian oscars...
Boeck, Gudrun de; Wood, Chris M.; Iftikar, Fathima I.; Matey, Victoria E.; Scott, Graham R.; Sloman, Katherine A.; Nazar Paula da Silva, Maria deOscars are often subjected to a combination of low levels of oxygen and fasting during nest-guarding on Amazonian floodplains. We questioned whether this anorexia would aggravate the osmo-respiratory compromise. We compared fed and fasted oscars (1014 days) in both normoxia and hypoxia (1020 Torr, 4 h). Routine oxygen consumption rates (MO2) were increased by 75% in fasted fish, reflecting behavioural differenc...