The effects of cocaine and denervation on the sensitivity to noradrenaline,its uptake and the termination of its action in isolated venous tissue

Summary The action of staphylococcal alpha toxin (ST) on potential difference (PD) and short-circuit current (SCC) of the isolated frog skin was studied. Ringer solution bathed the corial side and 20 mM NaCl bathed the epidermal side. PD and SCC decreased to about half after the administration of ST to the corial side of the skin. Later, SCC raised considerably. The replacement of 20 mM NaCl by KCl on the epidermal side of the ST-pretreated skin did not cause any substantial decrease of PD, while in the untreated skin the same replacement caused a sharp drop of PD. No secondary increase of SCC was observed after ST administration when the Ringer solution bathing the corial side of the skin contained 1/2 S0₄^– instead Cl^–. In contrast to the normal skin, dilution from 120 to 2 mM of the NaCl solution on the epidermal side led to a PD increase in the toxin-treated skin.Na⁺ fluxes across the skin in both directions were measured by means of radioisotopes. The direction of net flux of Na⁺ was reversed after treatment with the toxin. The results demonstrated two phases of ST action. Na⁺ transport is damaged in the first phase; in the second phase an outflux of Cl^– is induced.The changes of water permeability of the frog urinary bladder were determined by weighing bags formed from the bladders. The addition of the toxin to the medium bathing the serosal side resulted in increased weight losses. The transport of water was increased.A preliminary account of some of these results was presented (Kadlec and apek, 1969).