<prompt> Which of the following drug shows the phenomenon of vasomotor reversal of Dale after administration of an Alpha adrenergic blockerAdrenalineNor-adrenalineIsoprenalineAll of the above  <response>: Ref-KDT 6e p123 vasomotor reversal ot dale is seen with adrenaline. When this drug is infused quickly, initially there is rise in blood pressure due to sitmulation of a receptors followed by prolonged fall beta2 action. alpha-blocking drugs inhibit the initial rise and only fall in blood pressure is recorded. This is known as vasomotor reversal. Nor-adrenaline has no beta2 activity and isoprenaline lacks a activity, therefore cannot demonstrate this phenomenon. 