Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references
Phenethylamine, or β-Phenylethylamine (2-Phenylethylamine), is an alkaloid and monoamine. Phenethylamine has also structural isomer α- or 1-phenylethylamine, which has two stereoisomers: (R)-(+)-1-phenylethylamine and (S)-(-)-1-phenylethylamine. In the human brain, 2-phenethylamine is believed to function as a neuromodulator or neurotransmitter (trace amine). Phenethylamine is a natural compound biosynthesized from the amino acidphenylalanine by enzymatic decarboxylation. It is also found in many foods such as chocolate, especially after microbialfermentation. It has been suggested that phenethylamine from food may have psychoactive effects in sufficient quantities. However, it is quickly metabolized by the enzyme MAO-B, preventing significant concentrations from reaching the brain.
Phenethylamine (PEA) is an aromatic amine, which is a colorless liquid at room temperature. It is soluble in water, ethanol, and ether. Similar to other low-molecular-weight amines, it has a fishy odor. Upon exposure to air, it forms a solid carbonate salt with carbon dioxide. Phenethylamine is strongly basic and forms a stable crystalline hydrochloride salt with a melting point of 217 °C. Phenethylamine is also a skin irritant and possible sensitizer.
Infusion of PEA increased extracellular levels of dopamine while at the same time inhibiting DA neuron firings. It also modulates noradrenergic transmission. It has GABAergic antagonism.
Low levels are found in ADHD and often in depression, while levels are elevated in schizophrenia. This is associated with low dopamine in ADHD and depression and high dopamine in schizophrenia.
Chocolate theory of love
In the early 1980s, chemistry of love researcher Michael Libowitz, author of the popular 1983 book The Chemistry of Love, remarked to reporters that "chocolate is loaded with PEA." This became the focus for an article in The New York Times, which was then taken up by the wire services, then by magazine free-lancers, and evolved into the now-eponymous "chocolate theory of love." However, as noted earlier, phenethylamine is rapidly metabolized by the enzyme MAO-B, preventing significant concentrations from reaching the brain, thus contributing no perceptible psychoactive effect.
Substituted phenethylamines carry additional chemical modifications at the phenyl ring, the sidechain, or the amino group:
Substituted Amphetamines are homologues of phenethylamines carrying an alpha-methyl (α-CH3) group at the sidechain carbon atom next to the amino group.
Some of the more important phenethylamines are tabulated below. For simplicity, the stereochemistry of the sidechain is not covered in the table. Hundreds of other simple synthetic phenethylamines are known. This is due in part to the pioneering work of Alexander Shulgin, much of which is described in the book PiHKAL.
Substituted phenethylamines, tabulated by structure
^ Nakamura, Ishii, Nakahara. "Characterization of β-phenylethylamine-induced monoamine release in rat nucleus accumbens : a microdialysis study". European journal of pharmacology.
^ Kota Ishida, Mikio Murata et al.. "Effects of -Phenylethylamine on Dopaminergic Neurons of the Ventral Tegmental Area in the Rat: A Combined Electrophysiological and Microdialysis Study". Journal of Pharmacology And Experimental Therapeutics Fast Forward.
^ EM Parker and LX Cubeddu. "Comparative effects of amphetamine, phenylethylamine and related drugs on dopamine efflux, dopamine uptake and mazindol binding".
^ I. A. Paterson. "The potentiation of cortical neuron responses to noradrenaline by 2-phenylethylamine is independent of endogenous noradrenaline". Neurochemical Resarch.