Intracellular ph in cold-blooded vertebrates as a function of body temperature

https://doi.org/10.1016/0034-5687(76)90083-9Get rights and content

Abstract

Intracellular pH (pHi) was measured in vivo in tissue of frogs (Rana catesbeiana) and turtles Pseudemys scripta using the DM0 technique. Animals were permitted 3–8 days to come to a new steady-state body temperature (Tb) which ranged 5–32 °C. Least squares regression equation for pHi, data are: frog blood, 8.184-0.0206 Tb; frog striated muscle, 7.275-0.0152 Tb; turtle blood, 8.092-0.0207 Tb turtle muscle, 7.421-0.0186 Tb; turtle heart, 7.452-0.0122 Tb turtle liver, 7.753-0.0233 Tb; turtle esophageal smooth muscle, 7.513-0.0141 Tb. Only turtle cardiac muscle δpHi/|gdT was significantly different from δpH/δT of blood.

Results have been interpreted in terms of protein charge state alterations; in the physiological pH range, histidine residues of proteins are the principal dissociable groups (HPr+ = H++Pr) affected by pHi, and Tb changes. Constancy of protein charge state can be assessed by monitoring alpha imidazole, αInspim = Pr(HPr+ + Pr). A uniform pKim of 6.85 (20 °C) and a δHo of 7 kcal/mol are. assumed in calculating αim. Intracellular αim is preserved in the tissues studied as body temperature changes. These results indicate that ectothenn acid—base balance, alphastat control, regulates not only extracellular blood proteins, but also intracellular compartment proteins in such a way as to preserve functions dependent upon protein net1 charge states.

References (31)

  • D.C. Jackson

    The effect of temperature on ventilation in the turtle

    Pseudemys scripta elegans. Respir. Physiol.

    (1971)
  • D.C. Jackson et al.

    Effects of temperature transients on gas exchange and acid-base status of turtles.

    Am J. Physiol.

    (1976)
  • R.P. Kernan
  • R.N. Khuri et al.

    Intracellular bicarbonate in single skeletal muscle fibers

    Pflügers Arch.

    (1974)
  • P.G. Kostyuk et al.

    On the mechanism of hydrogen ion distribution between cell protoplasm and the medium

  • Cited by (90)

    • The thermodynamic soliton theory of the nervous impulse and possible medical implications

      2022, Progress in Biophysics and Molecular Biology
      Citation Excerpt :

      In fact, it has been shown that the pH of frog muscle changes as a function of temperature. It is about 7.4 at 4 °C and about 6.9 at 37 °C, i.e., about half a pH unit between the two temperatures ((Marjanovic et al., 1998)) (Malan et al., 1976). report a pH-change of −0.0147 pH units per degree in frog muscle.

    • pH regulation in hibernation: Implications for ventilatory and metabolic control

      2019, Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology
      Citation Excerpt :

      For example, the active site of lactate dehydrogenase requires protonated histidine residues to bind its substrate pyruvate. Regulating αim in vitro has been shown to reduce the changes in Michaelis–Menten constant (Km; the concentration of substrate at which the rate of enzymatic reaction is half of maximum rate) of lactate dehydrogenase with decreasing temperature (Yancey and Somero, 1978) and alpha-stat regulation of intracellular pH (pHi) has been demonstrated in various tissues of heterothermic vertebrates (Malan et al., 1976; Walsh and Moon, 1983; Bock et al., 2001). Air-breathing vertebrates generally maintain an extracellular pH (pHe) that is alkaline relative to pHnw, but the degree of relative alkalinity varies between vertebrate groups.

    • The cooperative actuation of multistep electrochemical molecular machines senses the working temperature: voltammetric study

      2017, Electrochimica Acta
      Citation Excerpt :

      In addition, those muscles sense by themselves the chemical and physical working conditions while actuating: they are haptic muscles [3]. The environmental temperature has a strong influence on the muscular reactions of any cold-blooded animal (ectotherm) [4–8]. The underlying working mechanism and the origin of the awareness of the thermal working conditions, remains as a controversial subject.

    • A critical evaluation of automated blood gas measurements in comparative respiratory physiology

      2014, Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology
      Citation Excerpt :

      The apparent similarity in temperature dependency among turtle, snake and human blood, indicates that potential differences in non-bicarbonate buffer capacity caused by differences in the number of histidine residues in proteins and the total protein concentration (see Jensen, 1989; Berenbrink, 2006) had negligible effects on the pH temperature dependency (i.e. Rosenthal, 1948; Reeves, 1976). The pH temperature dependency of human blood has been reported to be − 0.0147 pH°C− 1 (Rosenthal, 1948), while a value of − 0.0207 pH°C− 1 was found for T. scripta (Malan et al., 1976). This fits well with the present data as the error between GEM pH and BMS pH caused by the slight displacement of the regression is around .05 pH units (Table 2 and Fig. 6).

    • Therapeutics

      2006, Reptile Medicine and Surgery
    View all citing articles on Scopus
    1

    Present address: CNRS, Laboratoire de Physiologie Respiratoire, 67087 Strasbourg, France.

    View full text