Adrenoreceptors or adrenergic receptors are neuroreceptors that are sensitive to the neurotransmitters epinephrine (adrenaline) and norepinephrine.
Epinephrine is a neurotransmitter that creates abrupt bursts of energy and is part of the "fight or flight" response while norepinephrine facilitates responses to stressful situations. These neurotransmitters are key players in the Adrenergic System.
There are two kinds of adrenoreceptors:
1. Alpha receptors - they stimulate the excitatory responses of smooth muscle cells to the hormones secreted by the adrenal glands called catecholamines. 2. Beta receptors - unlike the alpha receptors, they decrease excitatory responses.