The action of beta adrenergic site stimulating, catecholamines on isolated frog skin

Abstract

Living frogs injected with the beta adrenergic site stimulating catecholamine ethylnopinephrine secrete a mucous containing equal amounts of Na + and Cl −. Isolated short circuited frog skin treated with beta adrenergic site stimulating catecholamine, including protokylol (Caytine) and isopropylarterenol, produce an outflux of Na + equal to a concomitant outflux of Cl − as measured with radioisotopes of Na + and Cl +, Na + influx and short circuit current is also stimulated equally. We conclude that two independent mechanisms are stimulated by these catecholamines: when used at 0.1 μM concentrations, Na + transport is stimulated; when used to 10 μM concentrations, as secretion of mucous containing Na + and Cl − is additionally stimulated. This conclusion is not in agreement with the results of a previously published investigation. In that study isopropylarterenol was reported to stimulate the production of a non-Na + short circuit current, presumably of Cl −. The conflict results, perhaps from not using radiosotopic Cl + in the investigation and therefore missing correspondence between Na + and Cl + outflux, and between Na + influx and short circuit current.