Question

Binding of norepinephrine or epinephrine to a(n) ________ receptor will activate an inhibitory G protein which decreases the activity of adenylate cyclase and therefore cAMP synthesis while the binding of these two neurotransmitters to a ________ receptor will do the exact opposite

Answer 1

α2 : β1

Step-by-step explanation:

1. Norepinephrine and epinephrine are very similar neurotransmitters and hormones.

2. Epinephrine has slightly more of an effect on heart, while norepinephrine has more of an effect on blood vessels. Both play a role in body's natural fight-or-flight response to stress and they also have important medical uses as well.

3. Binding of norepinephrine or epinephrine to an α2 receptor will activate an inhibitory G protein ( a G protein coupled receptor) which decreases the activity of adenylate cyclase and so on cAMP synthesis, and while the binding of these two neurotransmitters to a β1 receptor will do the exact opposite effect.

Answer 2

Epinephrine

Step-by-step explanation:

Epinephrine uses classical G protein coupled receptor (GPCR) signaling pathway by four different types of membrane receptors in different tissues:

`\alpha`1,
`\alpha 2`,
`\beta 1` and
`\beta 2`

Binding of non-epinephrine or epinephrine to an
`\alpha 2` receptor activates an inhibitory G protein called GI, GI activates cyclic nucleotide phosphodiesterase enzyme which converts cyclic AMP to 5' AMP thus destroys secondary messenger(cAMP)

`\beta 1` receptor associated trimeric G protein is GS which activate adenylate cyclase enzyme which catalyze production of a potent secondary messenger called cAMP