Question

You are a scientist studying how the circulatory system responds to the hormone epinephrine. You cut out blood vessels from the skin of many anesthetized rats and apply either epinephrine or saline to them. They all dilate in response to epinephrine but not the saline.

Feeling confident, you tell your friend in the lab that epinephrine dilates blood vessels. Your friend tries it out; she takes blood vessels, but from the gut this time, and applies either epinephrine or saline to them. But, she tells you that her blood vessels all constrict in response to epinephrine.

Assume that both you and your friend are good, careful scientists. What might be going on? What are two different molecular mechanisms for both you and your friend to be correct? Explain your reasoning. (roughly two sentences)

Answer 1

Ephinephrine binds to adrenergic receptors and leads to either vasoconstriction or vasodilation based on the subtype of adrenergic receptor present in different locations. Since , epinephrine is a fight or flight hormone, epinephrine binds to beta adrenergic receptor it causes vasodilation in the heart, skeletal muscles etc which require greater blood flow during adverseadverse conditions when epinephrine is secreted by sympathetic nervous system whereas binding of epinephrine to the alpha 1 adrenergic receptor in the gut causes vasoconstriction as blood flow is redirected from digestive processes to muscles etc which are required to be more active under adverse conditions.