Intracellular calcium as a modulator of transepithelial permeability to water in frog urinary bladder.
Open Access
- 1 March 1978
- journal article
- research article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 76 (3), 787-791
- https://doi.org/10.1083/jcb.76.3.787
Abstract
The divalent cation ionophore A 23187 was used to evaluate the action of intracellular calcium on net transepithelial water movement across the isolated frog urinary bladder. Incubation with the ionophore increases the net basal water flux in a dose-dependent fashion but independent of the extracellular calcium concentration. Bladders pretreated with A 23187 and exposed thereafter to an increase in calcium concentration exhibit a water permeability that under certain conditions can be comparable to that achieved with antidiuretic hormone (ADH). Lowering the serosal calcium at the peak of the hydrosmotic responses to both ADH and A 23187 inhibited the maintenance of the net water flux. The action of a supramaximal dose of ADH is blunted in bladders pretreated with A 23187, while the hydrosmotic effects of a submaximal dose are enhanced when the ionophore is added together with the hormone. The results show that an increase in transepithelial water movement can be triggered by calcium and that serosal calcium is needed to sustain the response. This hydrosmotic response may be dependent upon the rate at which intracellular calcium concentrations change and on the absolute concentration attained. It is suggested that calcium is involved in the action of ADH on water permeability and may act as a modulator of the hydrosmotic response.This publication has 7 references indexed in Scilit:
- Relationships between calcium and cyclic nucleotides in cell activation.Physiological Reviews, 1977
- Cellular actions of vasopressin in the mammalian kidneyKidney International, 1976
- Stimulus-response coupling in neurohypophysial peptide target cellsPhysiological Reviews, 1975
- Calcium release in relation to permeability changes in toad bladder epithelium following antidiuretic hormoneThe Journal of Physiology, 1974
- Lithium-induced ADH resistance in toad urinary bladdersKidney International, 1973
- HORMONE-STIMULATED EXOCYTOSIS IN THE TOAD URINARY BLADDERThe Journal of cell biology, 1972