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Titolo:
BALANCING HYPOXIA AND HYPOTHERMIA IN COLD-SUBMERGED FROGS
Autore:
TATTERSALL GJ; BOUTILIER RG;
Indirizzi:
UNIV CAMBRIDGE,DEPT ZOOL,DOWNING ST CAMBRIDGE CB2 3EJ ENGLAND
Titolo Testata:
Journal of Experimental Biology
fascicolo: 6, volume: 200, anno: 1997,
pagine: 1031 - 1038
SICI:
0022-0949(1997)200:6<1031:BHAHIC>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
CUTANEOUS GAS-EXCHANGE; ACID-BASE STATUS; RANA-CATESBEIANA; BUFO-MARINUS; TEMPERATURE REGULATION; ANURAN AMPHIBIANS; BLOOD; METABOLISM; PIPIENS; WATER;
Keywords:
RANA TEMPORARIA; FROG; OXYGEN; OVERWINTERING; HIBERNATION; BEHAVIORAL HYPOTHERMIA; ACID-BASE BALANCE; TEMPERATURE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
40
Recensione:
Indirizzi per estratti:
Citazione:
G.J. Tattersall e R.G. Boutilier, "BALANCING HYPOXIA AND HYPOTHERMIA IN COLD-SUBMERGED FROGS", Journal of Experimental Biology, 200(6), 1997, pp. 1031-1038

Abstract

Many animals respond to hypoxic stress by selecting cooler environments, the so-called 'behavioural hypothermia' response. Amphibians overwintering in ice-covered ponds and lakes offer an ecologically relevanttest of this response since they must choose between the confounding metabolic effects of profound hypothermia or hypoxia; thermal and chemical conditions can vary from 0 degrees C and normoxic at the ice-water interface to 4 degrees C and markedly hypoxic at depths of 2-4m. To mimic such environmental conditions, we constructed an experimental chamber that enabled continuous electronic surveillance of an animal's movement along a thermal gradient. When Rana temporaria pre-acclimated to 3.5 degrees C were placed in a normoxic thermal gradient ranging from 0.8 to 8 degrees C, they invariably favoured the warmer end of the chamber. Upon exposure to hypoxia, however, their preferred temperature shifted from a median of 6.8 degrees C (P-o2=158mmHg; 1mmHg=0.133kPa) to 1.9 degrees C (P-o2=25mmHg). Metabolic rate measurements from animals exposed simultaneously to acute changes in water temperature and P-o2 suggest that movement to colder conditions in hypoxia effects thegreatest metabolic savings and prolongs the onset of a plasma lactacidosis.

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Documento generato il 03/07/20 alle ore 22:29:46