Hi there,

I am a medical student and with my general physiology exam approaching, we wondered something with friends! We looked everywhere online but couldn't find the answer! The professor probably won't bother us with that but we still wanna know.


So adrenergic beta two receptors increase cAMP production when stimulated, inducing a relaxation of smooth muscle cells (via MLCP activation and all that), correct? This will therefore dilate blood vessels.

Adrenergic beta one receptors in kidneys will stimulate renin production, which will activate Angiotensin I then II, producing a vasoconstriction.


How can two adrenergic receptors have opposite effects? Am I mistaking somewhere or is it just a question of location of these vessels? But as hormones, Ang I and II should act everywhere as transported by blood...


Imagine epinephrine is released by sympathetic nervous system in case of stress, it will activate both receptors. The response from the bronchi and the blood vessels seems logical, but renin goes against all that? Constricting blood vessels will not be beneficent...


Sorry for my english mistakes, english isn't my native language so it's not always easy


Thanks for your answers!

Aurelien