Vasomotor reversal of dale is demonstrated by
**Core Concept**
Vasomotor reversal of Dale refers to the phenomenon where a vasoconstrictor agent, initially causing blood vessels to constrict, eventually leads to vasodilation. This reversal is caused by the exhaustion of the vasoconstrictor stores and the subsequent release of vasodilatory substances.
**Why the Correct Answer is Right**
The correct answer involves the concept of vasomotor reversal of Dale, which is typically demonstrated by the use of tyramine. Tyramine initially causes vasoconstriction by releasing stored norepinephrine from the nerve endings, but eventually, it leads to vasodilation due to the depletion of norepinephrine stores and the subsequent release of vasodilatory substances such as prostaglandins and histamine.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the phenomenon of vasomotor reversal of Dale.
**Option B:** This option is incorrect because it does not demonstrate the reversal of vasomotor tone, instead, it maintains vasoconstriction.
**Option C:** This option is incorrect because it does not accurately describe the mechanism of vasomotor reversal of Dale.
**Clinical Pearl / High-Yield Fact**
Tyramine-induced vasomotor reversal of Dale is an important concept in pharmacology, highlighting the complex interactions between vasoconstrictor and vasodilatory substances.
**Correct Answer: D. Tyramine**