Which of the following drug shows the phenomenon of vasomotor reversal of Dale after administration of an Alpha adrenergic blocker
High-Yield Explanation
Ref-KDT 6/e 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.