Patterns of acid-base regulation in urodele amphibians in response to variations in environmental temperature

Hicks, George H; Stiffler, Daniel F.

doi:10.1016/0300-9629(84)90187-7

Cited by 11 publications

(5 citation statements)

References 16 publications

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“…were similar to previous findings for the species at 15 "C (Hicks and Stiffler 1984). Larvae exposed to ambient pH 5.5 and 4.5 showed significant decreases in blood pH ( P < 0.05, Fig.…”

Section: Resultssupporting

confidence: 92%

Acid–base and electrolyte responses to low pH maintained by phosphate–citrate buffers in the bathing medium of the larval salamander Ambystoma tigrinum

DeRuyter¹,

Stiffler²

1988

Can. J. Zool.

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DERUYTER, M. L., and STIFFLER, D. F. 1988. Acid-base and electrolyte responses to low pH maintained by phosphatecitrate buffers in the bathing medium of the larval salamander Ambystoma tigrinum. Can. J. Zool. 66: 2383 -2389. Larval Ambystoma tigrinum were exposed to an external pH of 3.5 to 7.5 using phosphate-citrate buffers in the bathing medium. Blood analysis of cannulated Ambystoma tigrinum at pH 5.5, 4.5, and 3.5 indicated their ability to maintain relatively stable arterial pH at the two higher values; however, at pH 3.5, the blood pH diminished over the 12-h period before death. The greater stability of arterial pH at higher external pH is partially due to a reversal of an initial increase in arterial Pco,. This may not be due entirely to pulmonary excretion of CO, as it also occurred in animals that were forced to exchange gases solely across the skin-gill unit by being deprived of access to an air space. This result suggests increased skin-gill perfusion and (or) ventilation as a mechanism for lowering arterial Pco,. Sodium transport across the skin of A. tigrinum was measured over a buffered pH range of 3.5 to 7.5. Na+ influx decreased from 1.0 + 0.

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“…were similar to previous findings for the species at 15 "C (Hicks and Stiffler 1984). Larvae exposed to ambient pH 5.5 and 4.5 showed significant decreases in blood pH ( P < 0.05, Fig.…”

Section: Resultssupporting

confidence: 92%

Acid–base and electrolyte responses to low pH maintained by phosphate–citrate buffers in the bathing medium of the larval salamander Ambystoma tigrinum

DeRuyter¹,

Stiffler²

1988

Can. J. Zool.

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“…The CSF is in close, diffusive contact with the arterial blood and values of pH, P CO2 and [HCO 3 Ϫ ] in the blood are considered good approximations to those in the CSF and extracellular media. Studies of the blood acid-base balance in larval tiger salamanders (Burggren & Wood, 1981;Hicks & Stiffler, 1984) show that the normal pH of arterial blood is close to 7.8 over the temperature range 58C to 258C. The blood concentration of bicarbonate is known to be significantly temperature dependent with values near 26 mM at 208C reported by Hicks and Stiffler and about 13 mM by Burggren and Wood.…”

Section: Discussionmentioning

confidence: 96%

“…What should we expect if, instead of using Ringer's, we apply moist air or oxygen to an eyecup preparation? The partial pressure of CO 2 in air at sea level is 0.36 mm Hg, barely 3% of that in the blood stream (Burggren & Wood, 1981;Hicks & Stiffler, 1984), so we would expect an eyecup preparation, gassed with air or oxygen, to have lower than normal levels of HCO 3…”

Section: Buffering the Ph Of Experimental Solutionsmentioning

confidence: 99%

Effects of bicarbonate versus HEPES buffering on measured properties of neurons in the salamander retina

Hare

Owen

1998

Vis Neurosci

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Electrophysiological studies of the isolated retina involve perfusing the tissue with a physiological Ringer's. Organic pH buffers such as HEPES have become increasingly popular in recent years because for many purposes they offer a convenient and reliable alternative to the more traditional bicarbonate/CO2. In this paper, however, we report that important functional properties of rods, bipolar cells, and horizontal cells in the salamander, Ambystoma tigrinum, are sensitive to the choice of buffer and, in the case of horizontal cells, that sensitivity is acute. In bicarbonate/CO2 Ringer's, the dark potential of the horizontal cell was typically near -50 mV and saturating light caused it to hyperpolarize to about -75 mV. On switching to HEPES-buffered Ringer's at the same pH, horizontal cells depolarized in darkness to about -20 mV, close to the chloride equilibrium potential, and the kinetics of their light responses changed. The cone-driven components of light responses increased in size relative to rod-driven components. Saturating lights still hyperpolarized the cells to -75 mV, however. Horizontal cells, being coupled via gap junctions, form a syncytium and syncytial length constants, measured in bicarbonate/CO2 Ringer's, were generally in the range 150-225 microm. On switching to HEPES-buffered Ringer's, length constants increased substantially to 250-330 microm. All these changes were reversible. We discuss our findings within the context of the cell's ability to regulate its internal pH.

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“…Extant air-breathing fishes and aquatic amphibians inhabiting chronically hypercarbic environments have both a high P eo , and a high [HCO,-j (Table I). Randall and Cameron, 1973: (3) Cameron, 1980; (4) Heisler, 1982a: (5) Lenfant and Johansen, 1968; (6) Garey and Rahn, 1970;(7) Moalli et aI., 1981;(8) Hicks and Stiffler, 1984;(9) Heisler et aI., 1982;(10) Toews and Heisler, 1982;(II) Wood et aI., 1977;(12) Wood et aI., 1978;(13) Ultsch and Jackson, unpubl. exposing Necturus to water with a P co, of 22 mmHg at 25°C resulted in a high mortality. Necturus is well-adapted for aquatic respiration, with highly arborized external gills, the smallest body size of the group, and a gas-permeable skin.…”

Section: An Alternative Theory: the Effects Of Hypercarbia On Aquaticmentioning

confidence: 99%

The Potential Role of Hypercarbia in the Transition from Water-Breathing to Air-Breathing in Vertebrates

Ultsch¹

1987

Evolution

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Patterns of acid-base regulation in urodele amphibians in response to variations in environmental temperature

Cited by 11 publications

References 16 publications

Acid–base and electrolyte responses to low pH maintained by phosphate–citrate buffers in the bathing medium of the larval salamander Ambystoma tigrinum

Acid–base and electrolyte responses to low pH maintained by phosphate–citrate buffers in the bathing medium of the larval salamander Ambystoma tigrinum

Effects of bicarbonate versus HEPES buffering on measured properties of neurons in the salamander retina

The Potential Role of Hypercarbia in the Transition from Water-Breathing to Air-Breathing in Vertebrates

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