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Titolo:
Constant set points for pH and P-CO2 in cold-submerged skin-breathing frogs
Autore:
Tattersall, GJ; Boutilier, RG;
Indirizzi:
Univ Cambridge, Dept Zool, Cambridge CB2 3EJ, England Univ Cambridge Cambridge England CB2 3EJ ool, Cambridge CB2 3EJ, England
Titolo Testata:
RESPIRATION PHYSIOLOGY
fascicolo: 1, volume: 118, anno: 1999,
pagine: 49 - 59
SICI:
0034-5687(19991015)118:1<49:CSPFPA>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
CUTANEOUS GAS-EXCHANGE; ACID-BASE REGULATION; TEMPERATURE; AMPHIBIANS; BULLFROGS; HYPOXIA;
Keywords:
acid-base, overwintering frog; amphibians, frog; gas exchange, skin; overwintering, metabolism; temperature, overwintering;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
30
Recensione:
Indirizzi per estratti:
Indirizzo: Tattersall, GJ NE Ohio Univ, Coll Med, Dept Physiol, Rootstown, OH 44272 USA NE Ohio Univ Rootstown OH USA 44272 ootstown, OH 44272 USA
Citazione:
G.J. Tattersall e R.G. Boutilier, "Constant set points for pH and P-CO2 in cold-submerged skin-breathing frogs", RESP PHYSL, 118(1), 1999, pp. 49-59

Abstract

The low temperatures encountered by overwintering frogs result in a. largedownregulation of metabolism and behaviour. However, little is known aboutacid-base regulation in the extreme cold, especially when frogs become exclusive skin-breathers during their winter submergence. Blood and muscle tissue acid-base parameters (pH, P-CO2, bicarbonate and lactic acid concentrations) were determined in submerged frogs exposed to a range of low temperatures (0.2-7 degrees C). At overwintering temperatures between T = 0.2 and 4degrees C plasma pH and PCO2 were maintained constant, whereas intracellular pH regulation resulted in larger pH-temperature slopes occurring in the presumably more active heart muscle (Delta pH/Delta T = -0.0319) than in the gastrocnemius muscle (Delta pH/Delta T = -0.00799). Although blood pH wasnot significantly affected by submergence between 0.2 and 4 degrees C (pH = 8.220-8.253), it declined in the 7 degrees C frogs (pH = 8.086), a decrease not linked to the recruitment of anaerobiosis. Plasma P-CO2 and pH in the cold appear to be regulated at constant levels, implying that cutaneous CO2 conductance in submerged frogs is adjusted within the range of overwintering temperatures. This is likely geared toward facilitating the uptake of oxygen under conditions of greater metabolic demand, however there remains the: possibility that acid-base balance itself is maintained at a constant set point at the frog's natural overwintering temperatures. (C) 1999 Elsevier Science B.V. All rights reserved.

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Documento generato il 03/07/20 alle ore 01:40:00