HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by de Sousa, R. C. Articles by Grosso, A. Search for Related Content PubMed PubMed Citation Articles by de Sousa, R. C. Articles by Grosso, A.

Department of Physiology, School of Medicine, University of Geneva, 1211 Geneva 4, Switzerland

Department of Medicine, School of Medicine, University of Geneva, 1211 Geneva 4, Switzerland

1. Net water flow J_w, was measured across the abdominal skin of the toad Bufo marinus with a volumetric, automatic technique that allows for averaging J_w over time intervals as short as 1 sec.

2. Basal J_w was very stable and corresponded to a coefficient of osmotic flow, L_PD, of ca. 15 x 10^-7 cm sec^-1 atm^-1 (or to an osmotic water permeability coefficient, P_f, of 20 µm sec^-1).

3. Both vasopressin and the -adrenergic agonist, isoprenaline, triggered high hydrosmotic responses that could lead to P_f values exceeding 250 µm sec^-1. The effect of isoprenaline was very reproducible while that of vasopressin varied considerably.

4. Methohexital and propranolol selectively inhibited the hydrosmotic effects of vasopressin and isoprenaline, respectively, whereas amiloride and ouabain had no effect.

5. Mutual inhibition was found between vasopressin and isoprenaline in skins very sensitive to vasopressin. In less sensitive skins isoprenaline further increased J_w despite exposure of the epithelia to supramaximal concentrations of vasopressin.

6. Differential reactivity to vasopressin was found between the skin and the bladder taken from the same toad. In some instances, the bladder responded normally to vasopressin while the skin was totally unresponsive, suggesting the presence of osmoregulatory mechanisms exerting a local modulation of the vasopressin action in different target epithelia of the same animal.

This article has been cited by other articles:

				A. T. Hanna-Mitchell and E. M. Gebruers The hydroosmotic response of frog urinary bladder to serosal hypertonicity is dependent on adenylate cyclase for its maintenance and affected by [Cl-]o changes Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2006; 291(1): R213 - R223. [Abstract] [Full Text] [PDF]

				T. Hasegawa, H. Tanii, M. Suzuki, and S. Tanaka Regulation of Water Absorption in the Frog Skins by Two Vasotocin-Dependent Water-Channel Aquaporins, AQP-h2 and AQP-h3 Endocrinology, September 1, 2003; 144(9): 4087 - 4096. [Abstract] [Full Text] [PDF]