Norepinephrine is getting released from neurons, or, simply, nerve cells in the brain, which are called noradrenergic neurons, of course.The noradrenergic neurons in the brain form a sort of system, which is, in its turn, called norepinephrine system, that, when activated, exerts effects on large areas of the brain .
Chemicals responsible for our behavior in love and relationships belong to the class of "neurochemicals", compounds forming largely in the brain and participating in neural activity.
The brain, in its turn, passes them to other parts of the body, but "in the head" it all gets started.
Now you know that it is mostly dopamine which makes us feel good from the tasty food, and as far as PEA is concerned, it's role, unfortunately, has been exaggerated.
Phenethylamine from chocolate is getting rapidly metabolized by the different enzymes of gastrointestinal tract, preventing significant concentrations from reaching the brain.
Dopamine is the most mysterious of these three neurochemicals.
Arvid Carlsson was awarded the 2000 Nobel Prize in Physiology or Medicine for showing that dopamine is not just a precursor of norepinephrine but a neurotransmitter, as well. Nevertheless, when activated, the system plays major roles in the brain, Norepinephrine performs its actions on the target cells by binding to and activating its adrenergic receptors.The target cell expression of different types of receptors determines the ultimate cellular effect, and thus norepinephrine has different actions on different cell types.A state of becoming hypersocial, is also credited to an increase in dopamine. Large quantities of PEA increase both physical and emotional energy  and at the same time release more dopamine. Boston: Little, Brown, & Co  HIGH PRESSURE LIQUID CHROMATOGRAPHIC ANALYSIS OF TYRAMINE, PHENYLETHYLAMINE AND TRYPTAMINE IN SAUSAGE, CHEESE AND CHOCOLATE" P. So, we can say, that dopamine has a dual role: it can act as a neuromodulator and a neurotransmitter. PEA deserves a special attention because it is famous for being found in chocolate. Compare to the other two, PEA acts more as a neuromodulator rather than a neurotransmitter , .