Active sodium transport by the isolated toad bladder.
TLDR
The short-circuit current of the isolated toad bladder was regularly stimulated with pure oxytocin and vasopressin when applied to the serosal surface under aerobic and anaerobic conditions.Abstract:
Studies were made of the active ion transport by the isolated urinary bladder of the European toad, Bufo bufo, and the large American toad, Bufo marinus. The urinary bladder of the toad is a thin membrane consisting of a single layer of mucosal cells supported on a small amount of connective tissue. The bladder exhibits a characteristic transmembrane potential with the serosal surface electrically positive to the mucosal surface. Active sodium transport was demonstrated by the isolated bladder under both aerobic and anaerobic conditions. Aerobically the mean net sodium flux across the bladder wall measured with radioactive isotopes, Na(24) and Na(22), just equalled the simultaneous short-circuit current in 42 periods each of 1 hour's duration. The electrical phenomenon exhibited by the isolated membrane was thus quantitatively accounted for solely by active transport of sodium. Anaerobically the mean net sodium flux was found to be slightly less than the short-circuit current in 21 periods of observation. The cause of this discrepancy is not known. The short-circuit current of the isolated toad bladder was regularly stimulated with pure oxytocin and vasopressin when applied to the serosal surface under aerobic and anaerobic conditions. Adrenaline failed to stimulate the short-circuit current of the toad bladder.read more
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Route of passive ion permeation in epithelia.
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Effect of vasopressin and cyclic AMP on permeability of isolated collecting tubules
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TL;DR: The effect of vasopressin and cyclic 3’,5’-AMP on the permeability to water and urea of the isolated perfused rabbit collecting tubule was measured and permeability was not significantly altered despite simultaneous increases in water permeability.
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Amiloride: a potent inhibitor of sodium transport across the toad bladder
TL;DR: Amiloride inhibits Na transport and short‐circuit current (SCC) across the toad bladder through mucosal and serosal channels and is 1000 times more active at the mucosal than serosal surface.
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The mammalian urinary bladderan accommodating organ
TL;DR: Urinary bladders are found in the amphibia, chelonian reptiles and mammals and in these orders liquid urine is stored in the bladder and eliminated at intervals from the body by micturation.
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