5. ACID-BASE BALANCE
203
( 4 ) Bicarbonate leaves the red cells in exchange for chloride according to Donnan’s law.
(5) Carbonic acid also reacts with hemoglobin to form carbamino
hemoglobin.
( 6 ) Oxygenation of the hemoglobin decreases the buffer capacity
as well as the ability to form carbamino hemoglobin (Haldane effect) in
teleosts but not in elasmobranchs.
( 7 ) In the lungs or giHs the above-mentioned reactions occur in the
opposite direction.
IV. THE INTRACELLULAR pH
The rather complex processes of the CO, transport and the buffering
of carbonic acid and other acids in the blood are fairly simple when
compared with the analogous processes within the tissues. A comparative study of tissue CO, in several vertebrates has recently been published by Haning and Thompson (1965). In contrast to the blood, proteins are much less important as buffer substances. Some CO, within the
tissues seems to be bound in a carbaminolike fashion and cannot be precipitated by barium hydroxide (Conway and Fearon, 1944). There is
still some controversy about the chemical meaning of the so-called
“barium soluble fraction” of CO?. Data on this fraction are given for
several vertebrate tissues by Haning and Thompson (1965). In the
muscle of the channel catfish, Ictalurus punctatus, these authors found
70% of the tissue CO, to be barium soluble as compared with 77% in
rat muscle and 72% in frog muscle. As recently shown by Butler et al.
(1967) the “barium soluble C02” does not result from a carbaminolike
compound but from the inhibitory effect of proteins on the precipitation
of barium carbonate. As mentioned earlier the buffer capacity of tissues
is made up predominantly of inorganic and organic phosphate compounds. The total buffer capacity of tissues can well compete with that
of the blood in some organs of mammals (e.g., liver tissue of rats) although in most organs the buffer capacity is lower than in blood. The
buffer processes in the interior of a cell are closely linked to so many
biochemical reactions that a theoretical approach seems to be impossible.
The intracellular pH has been determined using a variety of methods
and has been found to be always lower than that of blood. Chambers
e t al. (quoted by Netter, 1959) reported for the nerve cells of fish a pH
of 6.8-6.9, based on a colorimetric indicator method. Electrometric pH
measurements have also been employed, yielding results comparable
203
( 4 ) Bicarbonate leaves the red cells in exchange for chloride according to Donnan’s law.
(5) Carbonic acid also reacts with hemoglobin to form carbamino
hemoglobin.
( 6 ) Oxygenation of the hemoglobin decreases the buffer capacity
as well as the ability to form carbamino hemoglobin (Haldane effect) in
teleosts but not in elasmobranchs.
( 7 ) In the lungs or giHs the above-mentioned reactions occur in the
opposite direction.
IV. THE INTRACELLULAR pH
The rather complex processes of the CO, transport and the buffering
of carbonic acid and other acids in the blood are fairly simple when
compared with the analogous processes within the tissues. A comparative study of tissue CO, in several vertebrates has recently been published by Haning and Thompson (1965). In contrast to the blood, proteins are much less important as buffer substances. Some CO, within the
tissues seems to be bound in a carbaminolike fashion and cannot be precipitated by barium hydroxide (Conway and Fearon, 1944). There is
still some controversy about the chemical meaning of the so-called
“barium soluble fraction” of CO?. Data on this fraction are given for
several vertebrate tissues by Haning and Thompson (1965). In the
muscle of the channel catfish, Ictalurus punctatus, these authors found
70% of the tissue CO, to be barium soluble as compared with 77% in
rat muscle and 72% in frog muscle. As recently shown by Butler et al.
(1967) the “barium soluble C02” does not result from a carbaminolike
compound but from the inhibitory effect of proteins on the precipitation
of barium carbonate. As mentioned earlier the buffer capacity of tissues
is made up predominantly of inorganic and organic phosphate compounds. The total buffer capacity of tissues can well compete with that
of the blood in some organs of mammals (e.g., liver tissue of rats) although in most organs the buffer capacity is lower than in blood. The
buffer processes in the interior of a cell are closely linked to so many
biochemical reactions that a theoretical approach seems to be impossible.
The intracellular pH has been determined using a variety of methods
and has been found to be always lower than that of blood. Chambers
e t al. (quoted by Netter, 1959) reported for the nerve cells of fish a pH
of 6.8-6.9, based on a colorimetric indicator method. Electrometric pH
measurements have also been employed, yielding results comparable