Adrenaline, anti-adrenaline drugs and potassium movements in rabbits auricles.

Adrenaline (2x10(-6) M) or isoprenaline (7.5x10(-8) M) increased the rate of (42)K 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 (42)K 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 (42)K uptake produced by adrenaline accounted entirely for the increase in potassium content of the tissue. Adrenaline, in concentrations ranging from 2x10(-6) M to 2x10(-4) M, had no effect on (42)K loss from electrically stimulated auricles. The action of adrenaline on (42)K uptake was blocked by dichloroisoprenaline (4x10(-6) M) but not by phenoxybenzamine (1.6x10(-6) M).