Temperature Dependence of Vasopressin Action on the Toad Bladder
Open Access
- 1 May 1972
- journal article
- Published by Rockefeller University Press in The Journal of general physiology
- Vol. 59 (5), 519-533
- https://doi.org/10.1085/jgp.59.5.519
Abstract
Toad bladders were challenged with vasopressin at one temperature, fixed on the mucosa with 1% glutaraldehyde, and then subjected to an osmotic gradient at another temperature. Thus, the temperature dependence of vasopressin action on membrane permeability was distinguished from the temperature dependence of osmotic water flux. As the temperature was raised from 20° to 38°C, there was a substantial increase in the velocity of vasopressin action, but osmotic flux was hardly affected. In this range of temperature the apparent energy of activation for net water movement across the bladder amounted to only 1.2 kcal/mole, a value well below the activation energy for bulk water viscosity. It is suggested that osmotic water flux takes place through narrow, nonpolar channels in the membrane. When the temperature was raised from 4° to 20°C, both vasopressin action as well as osmotic water flux were markedly enhanced. Activation energies for net water movement were now 8.5 kcal/mole (4°–9°C) and 4.1 kcal/mole (9°–20°C), indicating that the components of the aqueous channel undergo conformational changes as the temperature is lowered from 20°C. At 43°C bladder reactivity to vasopressin was lost, and irreversible changes in selective permeability were observed. The apparent energy of activation for net water movement across the denatured membrane was 6.6 kcal/mole. Approximately 1 µosmol of NaCl was exchanged for 1 µl of H2O across the denatured membrane.Keywords
This publication has 11 references indexed in Scilit:
- CORRELATION BETWEEN PINOCYTOSIS AND HYDROOSMOSIS INDUCED BY NEUROHYPOPHYSEAL HORMONES AND MEDIATED BY ADENOSINE 3',5'-CYCLIC MONOPHOSPHATEThe Journal of cell biology, 1971
- Effect of Geometrical and Chemical Constraints on Water Flux across Artificial MembranesThe Journal of general physiology, 1971
- Activation energy for water diffusion across the toad bladder: evidence against the pore enlargement hypothesisJCI Insight, 1971
- A cyclic AMP-dependent protein kinase from frog bladder epithelial cellsBiochemical and Biophysical Research Communications, 1970
- CYTOCHEMISTRY AND ELECTRON MICROSCOPYThe Journal of cell biology, 1963
- The State of Water in the Isolated Toad Bladder in the Presence and Absence of VasopressinThe Journal of general physiology, 1962
- Permeability of the Isolated Toad Bladder to Solutes and Its Modification by VasopressinThe Journal of general physiology, 1962
- STRUCTURE OF THE TOAD'S URINARY BLADDER AS RELATED TO ITS PHYSIOLOGYThe Journal of cell biology, 1961
- STUDIES ON THE MECHANISM OF ACTION OF VASOPRESSINProceedings of the National Academy of Sciences, 1960
- THE EFFECTS OF NEUROHYPOPHYSIAL EXTRACTS ON WATER TRANSFER ACROSS THE WALL OF THE ISOLATED URINARY BLADDER OF THE TOAD BUFO MARINUSJournal of Endocrinology, 1958