NaCl adaptation in Rana ridibunda and a comparison with the euryhaline toad Bufo viridis

1975 ◽  
Vol 63 (3) ◽  
pp. 763-773
Author(s):  
U. Katz
Keyword(s):  
Water Uptake ◽  
Sodium Transport ◽  
Tap Water ◽  
Physiological Adaptation ◽  
Salt Adaptation ◽  
Osmotic Gradient ◽  
Rana Ridibunda ◽  
Bufo Viridis ◽  
Water Frogs ◽  
Toad Bufo

The physiological adaptation of the frog Rana ridibunda to saline environment was studied. It was found that blood was always hypertonic to the external solution, but at the highest salinity tolerated (i.e. 300 mOsM) the osmotic gradient across the skin was nearly abolished. Water uptake by the living frog remained unchanged, whereas sodium transport across the skin decreased markedly. Neurohypophyseal hormone increased water uptake and sodium transport to levels similar to those in tap water frogs. Water content of the tissues was not affected by saline adaptation, although it varied appreciably under acute conditions. Oxygen consumption increased in dehydrated frogs, but not in adapted ones. The results are discussed and compared to the euryhaline toad Bufo viridis; the importance of high urea levels for high salt adaptation is stressed.

The Effect of Salt Adaptation and Amiloride on the In Vivo Acid-Base Status of the Euryhaline Toad Bufo Viridis

1981 ◽  
Vol 93 (1) ◽  
pp. 93-99
Author(s):  
U. KATZ
Keyword(s):  
Tap Water ◽  
Salt Adaptation ◽  
Acid Base ◽  
Bufo Viridis ◽  
Acid Base Status ◽  
Simultaneous Decrease ◽  
Toad Bufo

1. The acid-base status of the blood of the toad Bufo viridis was studied during adaptation to high salinity and in tap water containing amiloride. 2. Both salt adaptation and immersion for 2-3 days in 5 x10−4 M amiloride in tap water resulted in a decrease in blood pH (from 7.720 ± 0.026 in tap water to 7.456±0.051 in 500 mOsm NaCl-adapted toads; mean ± S.E.), and a simultaneous decrease in the concentration of HCO3- (from 17.8 ±1.4 in tap water to 9.5±1.2 in salt-adapted toads). 3. In vitro determination of Na+/H+ exchange across the skin showed a 1:1 relation in skins from tap-water-adapted toads; this exchange was inhibited by amiloride. H+ secretion was abolished in skins from salt-adapted toads and the uptake of sodium was reduced.

THE EFFECT OF THYROID HORMONES ON WATER PERMEABILITY OF THE ISOLATED BLADDER OF THE TOAD BUFO BUFO

1964 ◽  
Vol 28 (2) ◽  
pp. 205-211 ◽  
Author(s):  
K. GREEN ◽  
A. J. MATTY
Keyword(s):  
Oxygen Uptake ◽  
Sodium Transport ◽  
Driving Force ◽  
Water Movement ◽  
Bufo Bufo ◽  
Toad Bladder ◽  
Osmotic Gradient ◽  
Serosal Surface ◽  
Toad Bufo ◽  
Toad Bufo Bufo

SUMMARY Thyroxine at 10−6m concentration enhances water movement from the mucosal to the serosal surface of the isolated toad bladder in the absence of an osmotic gradient. It is suggested that this is caused by the effect of thyroxine on sodium transport which creates a driving force for the increased water movement. Thyroxine caused this effect when applied on either side of the membrane, but was more effective when applied to the serosal surface. Incubation of different bladders successively in the same triiodothyronine solution indicated that triiodothyronine may be rapidly utilized. A mixture of thyroxine and triiodothyronine caused a diphasic effect on water loss down an osmotic gradient. The analogues tetraiodothyroproprionic acid and tetraiodothyroformic acid had no effect on water movement down an osmotic gradient across the isolated toad bladder nor did they affect oxygen uptake or sodium transport. The results support the concept that thyroxine and triiodothyronine act on permeability processes in and across cell membranes.

scholarly journals Chloride transport in toad skin (Bufo viridis). The effect of salt adaptation

1984 ◽  
Vol 109 (1) ◽  
pp. 353-371 ◽  
Author(s):  
U. Katz ◽  
E. H. Larsen
Keyword(s):  
Chloride Transport ◽  
Tap Water ◽  
Phosphodiesterase Inhibitor ◽  
Flux Ratio ◽  
Salt Adaptation ◽  
Nacl Solution ◽  
Bufo Viridis ◽  
Spontaneous Potential ◽  
Activated State ◽  
Cl Conductance

The steady-state Cl- current across the skin of Bufo viridis adapted to tap water was found to be rectified. In skins bathed with NaCl Ringer on both sides, a large outward current, carried by influx of Cl-, was observed at a clamping voltage (V) of less than −50 mV (outside of the skin negative). for V = −50 mV the transepithelial Cl- conductance calculated from isotope flux measurements was 2.5 +/− 0.3 mS cm-2, N = 10. When the skin was clamped at + 50 mV the net flux of Cl- was reversed, but Cl- conductance was only 0.3 +/− 0.1 mScm-2. Flux ratio analysis indicated that the potential-activated Cl- conductance carries Cl- ions by way of passive transport. With NaCl Ringer bathing the outer surface of the skin the spontaneous potential was about −30 mV. At this potential the Cl- conductance of the skin was about half of its maximum value. The time course of Cl- current activation following a fast, stepwise change of V from 50 mV to a potential below O mV showed an initial delay of a few seconds, and proceeded with a halftime (T 1/2) which varied as a bell-shaped function of V. The maximum T 1/2 was about 100 s for V = −10 mV in skins exposed to KCl Ringer on the outside. Following adaptation of the toads to a 250 mM-NaCl solution, the fully activated Cl- conductance of the skin was greatly reduced, and the conductance-voltage curve was shifted to the left along the voltage-axis. With NaCl Ringer on the outside the spontaneous potential was about −20 mV, and Cl- conductance activation was possible only outside the physiological range of potentials. The time constant of Cl- conductance activation from closed to fully activated state was more than doubled following salt adaptation of the toads. The active inward Cl- flux disappeared in skins of toads adapted to a 250 mM-NaCl solution, and apparent leakage conductance was reduced. Application of the phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine to skin of fully salt-adapted toads increased the transepithelial Cl- conductance, and the time courses of voltage clamp currents became more like those of water-adapted toads. Apparent leakage conductance was increased.(ABSTRACT TRUNCATED AT 400 WORDS)

Urea transport across urinary bladder and salt acclimation in toad (Bufo viridis)

1990 ◽  
Vol 258 (4) ◽  
pp. R883-R888 ◽  
Author(s):  
S. Shpun ◽  
U. Katz
Keyword(s):  
Urinary Bladder ◽  
Tap Water ◽  
Water Flux ◽  
Inhibitory Effect ◽  
Facilitated Diffusion ◽  
Urea Transport ◽  
Bufo Viridis ◽  
Salt Acclimation ◽  
Osmotic Water ◽  
Toad Bufo

The fluxes of urea across the urinary bladder of the toad Bufo viridis have been studied under conditions of acclimation to tap water or 500 mosM NaCl solution. The [14C]urea fluxes were measured simultaneously with [3H]inulin to test for nonspecific leakage. The fluxes are quite high (Ktrans = 75 x 10(-7) cm/s at 5 mmol/l urea) and are similar in either the mucosal-to-serosal or the opposite direction. “Summer” rates were five to six times higher than the “winter” rates. Antidiuretic hormone (ADH), theophylline, and forskolin increased the fluxes to variable degrees (two to five times), similar in the two acclimation conditions. Phloretin inhibited the urea fluxes by nearly 50%. 1,3-Dimethylurea and thiourea, but not acetamide, competed with the urea fluxes effectively. The fluxes of urea were not affected by the osmotic water flow, although both responded to ADH. It is concluded that urea transport across the urinary bladder of B. viridis is by facilitated diffusion through a specific pathway independent of water flux. The inhibitory effect of the structural analogues on the urea flux was affected by salt acclimation, whereas most other characteristics did not differ significantly at 5 mmol/l external urea under the two conditions of acclimation.

THE EFFECTS OF VASOPRESSIN ON WATER UPTAKE OF THE TOAD, BUFO MARINUS, WHILE BATHED IN DIFFERENT HYPOTONIC SOLUTIONS

1957 ◽  
Vol 16 (2) ◽  
pp. 126-134 ◽  
Author(s):  
P. J. BENTLEY
Keyword(s):  
Sodium Chloride ◽  
Water Uptake ◽  
Tap Water ◽  
Bufo Marinus ◽  
Distilled Water ◽  
Three Solutions ◽  
Steady Decrease ◽  
Sodium Loss ◽  
Toad Bufo ◽  
Control Water

SUMMARY The uptake of water with and without vasopressin was measured in the intact toad, Bufo marinus. When injected with vasopressin, toads sitting in tap water showed a significantly greater response than those sitting in distilled water. NaCl solutions of increasing concentrations potentiated the uptake of water in response to vasopressin over part of the hypotonic range. If the NaCl level was kept constant and glucose used to increase the concentration, there was a steady decrease in response as the concentration was increased towards isotonicity with the animal's body fluids. Uptake of water in response to vasopressin was far greater in sodium chloride than in either lithium or potassium chloride of the same concentration. The control water uptake was similar in the three solutions. Large doses of vasopressin brought about an increase in sodium loss through the toad's skin. The theoretical implications of these results are discussed in relation to possible mechanisms involved in this uptake of water.

Sign in / Sign up

Export Citation Format

Share Document