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Titolo:
The protective effects of hypoxia-induced hypometabolism in the Nautilus
Autore:
Boutilier, RG; West, TG; Webber, DM; Pogson, GH; Mesa, KA; Wells, J; Wells, MJ;
Indirizzi:
Univ Cambridge, Dept Zool, Cambridge CB2 3EJ, England Univ Cambridge Cambridge England CB2 3EJ ool, Cambridge CB2 3EJ, England Dalhousie Univ, Dept Biol, Halifax, NS B3H 4J1, Canada Dalhousie Univ Halifax NS Canada B3H 4J1 iol, Halifax, NS B3H 4J1, Canada Univ Calif Santa Cruz, Dept Biol, Santa Cruz, CA 95064 USA Univ Calif Santa Cruz Santa Cruz CA USA 95064 l, Santa Cruz, CA 95064 USA
Titolo Testata:
JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTALPHYSIOLOGY
fascicolo: 4, volume: 170, anno: 2000,
pagine: 261 - 268
SICI:
0174-1578(200006)170:4<261:TPEOHH>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
BEHAVIOR; METABOLISM; POMPILIUS; LIFE;
Keywords:
Nautilus; hypometabolism; hypoxia; blood gases; pH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
28
Recensione:
Indirizzi per estratti:
Indirizzo: Boutilier, RG Univ Cambridge, Dept Zool, Downing St, Cambridge CB2 3EJ, England Univ Cambridge Downing St Cambridge England CB2 3EJ England
Citazione:
R.G. Boutilier et al., "The protective effects of hypoxia-induced hypometabolism in the Nautilus", J COMP PH B, 170(4), 2000, pp. 261-268

Abstract

Specimens of Nautilus pompilius were trapped at depths of 225 300 m off the sunken barrier reef southeast of Port Moresby, Papua New Guinea. Animals transported to the Motupore island laboratory were acclimated to normal habitat temperatures of 18 degrees C and then cannulated for arterial and venous blood sampling. When animals were forced to undergo a period of progressive hypoxia eventually to encounter ambient partial pressure of oxygen (PO2) levels Of similar to 10 mmHg land corresponding arterial PO2's of similarto 5 mmHg), they responded by lowering their aerobic metabolic rates to 5-10% of those seen in resting normoxic animals. Coincident with this profound metabolic suppression was an overall decrease in activity, with brief periods of jet propulsion punctuating long periods of rest, Below ambient PO2 levels of 30-40 mmHg, ventilatory movements became highly periodic and at the lowest PO2 levels encountered, ventilation occasionally ceased altogether. Cardiac output estimated by the Fick equation decreased during progressive hypoxia by as much as 75 80%, and in the deepest hypometabolic states heart rates slowed to one to two cycles of very low amplitude per minute. By the end of 500 min exposure to ambient PO2 levels of 10 mmHg or less, the anaerobic end products octopine and succinate had increased significantly inadductor muscle and heart, respectively. Increased concentrations of octopine in adductor muscle apparently contributed to a small intracellular acidosis and to the development of a combined respiratory and metabolic acidosis in the extracellular compartment, On the other hand, increases in succinate in heart muscle occurred in the absence of any change in cardiac pHi. Taken together, we estimate that these anaerobic end products would make up less than 2% of the energy deficit arising from the decrease in aerobic metabolism. Thus, metabolic suppression is combined with a massive downregulation of systemic O-2 delivery to match metabolic supply to demand.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/04/20 alle ore 05:03:37