THE EFFECT OF THIOPENTAL AND CATECHOLAMINES ON THE SODIUM FLUXES IN TOAD BLADDER

¹ Case Western Reserve University School of Medicine, Department of Anesthesiology, Cleveland, Ohio

Thiopental had a dual effect on Na⁺ transport (short-circuit current) and Na⁺ permeability of the isolated toad bladder. After bilateral application, transport was stimulated by lower concentrations and inhibited by higher concentrations. The stimulation was mediated through a site on the serosa and was blocked by alpha or beta receptor blocking agents. There was positive interaction on transport between thiopental and catecholamines on the serosa. The inhibition of transport was mediated through a site on the mucosa. Serosal thiopental or epinephrine appeared to decrease bladder permeability to Na⁺. On the mucosa, lower thiopental concentrations decreased and higher concentrations increased permeability.