ADRENALINE, ANTI‐ADRENALINE DRUGS AND POTASSIUM MOVEMENTS IN RABBIT AURICLES

Abstract

Adrenaline (2 × 10⁻⁶ m) or isoprenaline (7.5 × 10⁻⁸ m) increased the rate of ⁴²K uptake and the potassium content of right (spontaneously beating) auricles, but had no effect on potassium movements in quiescent left auricles. Although faster beating induced by electrical stimulation increased the rate of ⁴²K uptake, the actions of adrenaline were also apparent in auricles which were electrically stimulated so that they beat at a constant rate. The increase in ⁴²K uptake produced by adrenaline accounted entirely for the increase in potassium content of the tissue. Adrenaline, in concentrations ranging from 2 × 10⁻⁶ m to 2 × 10⁻⁴ m, had no effect on ⁴²K loss from electrically stimulated auricles. The action of adrenaline on ⁴²K uptake was blocked by dichloroisoprenaline (4 × 10⁻⁶ m) but not by phenoxybenzamine (1.6 × 10⁻⁶).