Question

You are crossing the street and almost get hit by a bus. As your fight or flight response kick in, describe the signaling pathway that occurs from epinephrine binding the b2-adrenergic receptor on your skeletal blood vessels.

Answer 1

The epinephrine binds to the beta 2 adrenergic receptor. This activates the G protein and then the GDP is converted to GTP. The GTP binds to the adenylate cyclase by activating it. This leads to the conversion of ATP to cyclic AMP. The cAMP activated the protein kinase. This then activates the inactive phosphorylase kinase. This activates phosphorylase b and there by increase the influx of calcium to the smooth muscles of the blood vessels. The cells contract and the blood vessel dialate. Thus more blood flows through the skeletal blood vessel.