Beta-Blockers Are a Class of Drugs That Target Beta-Adrenergic Receptors,blocking

Multiple Choice

Beta-blockers are a class of drugs that target beta-adrenergic receptors,blocking the action of epinephrine and norepinephrine.These drugs are used to treat heart conditions,hypertension,glaucoma,and migraine headaches and are also used off-label to alleviate stage fright in performers.Since the beta-adrenergic receptor is a GPCR,what intracellular event is prevented by the use of a beta-blocker?

A) a protein kinase cascade,initiated by the receptor's intracellular kinase domain
B) release of an activated G protein subunit bound to GTP
C) transport of the receptor-hormone complex into the cell and the nucleus,where it would regulate transcription
D) a protein phosphatase cascade,initiated by the receptor's intracellular phosphatase domain