3. CELLULAR ASPECTS OF ACTIVE TRANSPORT
173
TABLE XVI
EFFECT OF VERATRINE (4 μΜ) ON THE NA AND Κ CONTENT OF THE ISOLATED
VENTRAL NERVE CHAIN OF Homarus vulgaris L.
a,h
Sample
Na
Κ
Control
240
103
Veratrine
278
68.7
Control
249
100
Veratrine
301
65
a Gilles and Schoffeniels (135).
b Concentration given in microequivalents per gram fresh weight.
Despite the fact that the figures do not give the true values of the
cation content of the intracellular fluid, the values obtained after application of veratrine are significantly different and thus support the conclusion that veratrine at the concentration used affects the cation distribution in the same way as the stimulation does, i.e., increase in intracellular
Na concentration, decrease in intracellular Κ concentration.
Moreover, the results are consistent with our general assumption that
the metabolism of intracellular amino acids is directly dependent on the
ionic composition of the intracellular fluid.
The above results were obtained with a stenohaline species Homarus
vulgaris L. It is, however, interesting to consider them in relation to the
problem of the osmoregulatory function of amino acids in euryhaline
species. If the total amount of free amino acid within a cell is directly
related to the ionic composition of the intracellular liquid, at what level
should we search for the difference between eury- and stenohaline
species?
In Table XVII we give the total amount of free amino acid (exOur results using glucose-U-C
14 and pyruvate-l-C
14 and -2-C
14
show
that the labeling of amino acids can be affected by our experimental
conditions (Table XV).
It can be seen that the values of the control are different if we use
glucose-U-C
14
or pyruvate-l-C
14
as substrate. This is also true with
pyruvate-2-C
14
, and this aspect of the problem is discussed in full
detail elsewhere (135).
It is also evident that the results obtained with veratrine and during
electrical stimulation are identical since in both conditions we find an
increase in the labeling of the four amino acids isolated. This seems to
indicate a similar mode of action. We thus have measured the Na and
Κ content of the lobster ventral nervous chain before and after application of veratrine. The results are given in Table XVI.
173
TABLE XVI
EFFECT OF VERATRINE (4 μΜ) ON THE NA AND Κ CONTENT OF THE ISOLATED
VENTRAL NERVE CHAIN OF Homarus vulgaris L.
a,h
Sample
Na
Κ
Control
240
103
Veratrine
278
68.7
Control
249
100
Veratrine
301
65
a Gilles and Schoffeniels (135).
b Concentration given in microequivalents per gram fresh weight.
Despite the fact that the figures do not give the true values of the
cation content of the intracellular fluid, the values obtained after application of veratrine are significantly different and thus support the conclusion that veratrine at the concentration used affects the cation distribution in the same way as the stimulation does, i.e., increase in intracellular
Na concentration, decrease in intracellular Κ concentration.
Moreover, the results are consistent with our general assumption that
the metabolism of intracellular amino acids is directly dependent on the
ionic composition of the intracellular fluid.
The above results were obtained with a stenohaline species Homarus
vulgaris L. It is, however, interesting to consider them in relation to the
problem of the osmoregulatory function of amino acids in euryhaline
species. If the total amount of free amino acid within a cell is directly
related to the ionic composition of the intracellular liquid, at what level
should we search for the difference between eury- and stenohaline
species?
In Table XVII we give the total amount of free amino acid (exOur results using glucose-U-C
14 and pyruvate-l-C
14 and -2-C
14
show
that the labeling of amino acids can be affected by our experimental
conditions (Table XV).
It can be seen that the values of the control are different if we use
glucose-U-C
14
or pyruvate-l-C
14
as substrate. This is also true with
pyruvate-2-C
14
, and this aspect of the problem is discussed in full
detail elsewhere (135).
It is also evident that the results obtained with veratrine and during
electrical stimulation are identical since in both conditions we find an
increase in the labeling of the four amino acids isolated. This seems to
indicate a similar mode of action. We thus have measured the Na and
Κ content of the lobster ventral nervous chain before and after application of veratrine. The results are given in Table XVI.