Concentrating ability of the Bothrops jararaca gallbladder

Abstract

Total sodium, potassium, magnesium, calcium, chloride and osmolality were measured in plasma and gallbladder bile of the snake Bothrops jararaca under normal hydration conditions or in the presence of chronic challenges of hydromineral balance. The gallbladder region was also submitted to gross anatomic and microscopic examination. Different treatments did not produce changes in plasma calcium, and bile magnesium and potassium concentrations. Changes on plasma osmolality were mainly due to parallel changes on plasma sodium and chloride. Higher bile potassium, magnesium and calcium concentrations, lower chloride concentration, and osmolality and sodium concentrations near to plasma were found after all treatments. These results suggested the concentrating ability of the snake gallbladder related to hydroionic transport across the pseudostratified epithelium of this organ. Parallel changes on osmotic and electrolytic concentrations between bile and plasma indicated the absence of any effect of this concentrating ability on the entire hydromineral balance. Besides its involvement in the in vivo control of bile composition, the Bothrops jararaca gallbladder appears to be an interesting model for in vitro studies on transepithelial transport.