INHIBITION BY THE SYMPATHETIC OF ADRENALINE'S ACTION ON DOG'S HINDLIMB VASCULAR RESISTANCE

The action of intravenous adrenaline on the vascular resistance of the dog's hindlimb is altered when sympathetic stimulation is given either before or after the adrenaline. The increase in vascular resistance produced by adrenaline is greatly reduced immediately after the recovery of the blood flow from a reduction due to a brief sympathetic stimulation. This partial inhibition of adrenaline's action wears off in 6–12 min. Further, the effect of intravenous adrenaline follows a much shorter time course if during it the sympathetic is stimulated for a period of 2‐4 sec. The mechanism of this phenomenon is discussed. © 1969 The Physiological Societ