Mechanism of Action of Anti Diuretic Hormone on Transport Across Frog Skin

Abstract

The frog-skin is an ideal model to understand the various ion channels and transporters of the epithelium, which are involved in various ionic transport mechanisms to maintain intracellular ionic and osmotic concentration to perform vital functions of cells. They are studied by using specific blockers or stimulators of specific ionic conductance. AIM OF THE STUDY: To study the effect of ADH on transepithelial and transmembrane transport in frog skin. OBJECTIVES: newlineA. Intact and nystatin-permeabilized frog skins. 1. Intact skin: An ionic transport activity. 2. Action of ADH on intact skin. 3. Effect of ADH on nystatin-permeabilized skin bathed in apical KGS -1 solution. 4. Effect of ADH on nystatin-permeabilized skin bathed in apical KR solution (Sodium -free solutions). 5. Effect of ADH on nystatin-permeabilized skin bathed in SGS (chloride-free solutions). 6. Comparison of nystatin effect in apical KGS-1 and KR solutions. 7. Comparison of effect of ADH on nystatin-permeabilized skin bathed in KGS-1 and KR solutions. B. Action of amiloride and ouabain on frog skin and the lack of effect of ADH subsequently. 8. Action of amiloride on intact skin and the lack of effect of ADH subsequently. 9. Action of ouabain on the intact skin and the lack of effect of ADH subsequently. 10. Effect of ouabain in nystatin-permeabilized frog-skin (KGS-1). MATERIALS AND METHODS: The method used to study the effect of ADH on frog skin was Electrophysiology. ELECTROPHYSIOLOGY: The short circuit current (SCC) and current-voltage relations were measured by an electrophysiological method. For this study on frog skin the following materials were used. 1. A modified Ussing chamber. 2. Chloride coated Silver electrodes. 3. Salt bridges. 4. A computer-based voltage clamp circuit. Now considering the actions of ADH, the following results are important: CONCLUSION: ADH makes the TEPD more negative, increases the SCC, but does not change the conductance in the intact skin. 2. It follows that ADH increases sodium transport without affecting the conductance.