Stimulation of a1 adrenergic receptors by norepinephrine results in
A) an increase in the amount of intracellular cAMP.
B) a decrease in the amount of intracellular cAMP.
C) decreased membrane permeability to sodium ion.
D) release of calcium ions from intracellular stores.
E) increased membrane permeability to potassium ions.
Answer: D