Constant set points for pH and P(CO2) in cold-submerged skin-breathing frogs.

Title

Constant set points for pH and P(CO2) in cold-submerged skin-breathing frogs.

Creator

Tattersall G J; Boutilier R G

Publisher

Respiration physiology

Date

1999
1999-10

Description

The low temperatures encountered by overwintering frogs result in a large downregulation of metabolism and behaviour. However, little is known about acid-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 4 degrees C plasma pH and P(CO2) were maintained constant, whereas intracellular pH regulation resulted in larger pH-temperature slopes occurring in the presumably more active heart muscle (deltapH/deltaT = -0.0313) than in the gastrocnemius muscle (deltapH/deltaT = -0.00799). Although blood pH was not 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.

Subject

*Hydrogen-Ion Concentration; *Skin Physiological Phenomena; Acclimatization; Animals; Carbon Dioxide/blood/*metabolism; Cold Temperature; Immersion; Muscle; Oxygen/*metabolism; Partial Pressure; Rana temporaria/*physiology; Seasons; Skeletal/physiology

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

49–59

Issue

1

Volume

118

Citation

Tattersall G J; Boutilier R G, “Constant set points for pH and P(CO2) in cold-submerged skin-breathing frogs.,” NEOMED Bibliography Database, accessed September 18, 2021, https://neomed.omeka.net/items/show/3863.

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