Amphetamine is a central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and obesity. Amphetamine was discovered as a chemical in 1887 by Lazăr Edeleanu, and then as a drug in the late 1920s. It exists as two enantiomers: levoamphetamine and dextroamphetamine. Amphetamine properly refers to a specific chemical, the racemic free base, which is equal parts of the two enantiomers in their pure amine forms. The term is frequently used informally to refer to any combination of the enantiomers, or to either of them alone. Historically, it has been used to treat nasal congestion and depression. Amphetamine is also used as an athletic performance enhancer and cognitive enhancer, and recreationally as an aphrodisiac and euphoriant. It is a prescription drug in many countries, and unauthorized possession and distribution of amphetamine are often tightly controlled due to the significant health risks associated with recreational use.
A catecholamine is a monoamine neurotransmitter, an organic compound that has a catechol and a side-chain amine.
Monoamine neurotransmitters are neurotransmitters and neuromodulators that contain one amino group connected to an aromatic ring by a two-carbon chain (such as -CH2-CH2-). Examples are dopamine, norepinephrine and serotonin.
Phenelzine, sold under the brand name Nardil, among others, is a non-selective and irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class which is primarily used as an antidepressant and anxiolytic. Along with tranylcypromine and isocarboxazid, phenelzine is one of the few non-selective and irreversible MAOIs still in widespread clinical use.
Phenethylamine (PEA) is an organic compound, natural monoamine alkaloid, and trace amine, which acts as a central nervous system stimulant in humans. In the brain, phenethylamine regulates monoamine neurotransmission by binding to trace amine-associated receptor 1 (TAAR1) and inhibiting vesicular monoamine transporter 2 (VMAT2) in monoamine neurons. To a lesser extent, it also acts as a neurotransmitter in the human central nervous system. In mammals, phenethylamine is produced from the amino acid L-phenylalanine by the enzyme aromatic L-amino acid decarboxylase via enzymatic decarboxylation. In addition to its presence in mammals, phenethylamine is found in many other organisms and foods, such as chocolate, especially after microbial fermentation.
A biogenic amine is a biogenic substance with one or more amine groups. They are basic nitrogenous compounds formed mainly by decarboxylation of amino acids or by amination and transamination of aldehydes and ketones. Biogenic amines are organic bases with low molecular weight and are synthesized by microbial, vegetable and animal metabolisms. In food and beverages they are formed by the enzymes of raw material or are generated by microbial decarboxylation of amino acids.
Tyramine, also known under several other names, is a naturally occurring trace amine derived from the amino acid tyrosine. Tyramine acts as a catecholamine releasing agent. Notably, it is unable to cross the blood-brain barrier, resulting in only non-psychoactive peripheral sympathomimetic effects following ingestion. A hypertensive crisis can result, however, from ingestion of tyramine-rich foods in conjunction with the use of monoamine oxidase inhibitors (MAOIs).
Trace amines are an endogenous group of trace amine-associated receptor 1 (TAAR1) agonists – and hence, monoaminergic neuromodulators – that are structurally and metabolically related to classical monoamine neurotransmitters. Compared to the classical monoamines, they are present in trace concentrations. They are distributed heterogeneously throughout the mammalian brain and peripheral nervous tissues and exhibit high rates of metabolism. Although they can be synthesized within parent monoamine neurotransmitter systems, there is evidence that suggests that some of them may comprise their own independent neurotransmitter systems.
β-Methylphenethylamine is an organic compound of the phenethylamine class, and a positional isomer of the drug amphetamine, with which it shares some properties. In particular, both amphetamine and β-methylphenethylamine are human TAAR1 agonists. In appearance, it is a colorless or yellowish liquid.
Phenylethanolamine N-methyltransferase (PNMT) is an enzyme found primarily in the adrenal medulla that converts norepinephrine (noradrenaline) to epinephrine (adrenaline). It is also expressed in small groups of neurons in the human brain and in selected populations of cardiomyocytes.
Monoamine oxidase B, also known as MAO-B, is an enzyme that in humans is encoded by the MAOB gene.
Trace amine-associated receptor 1 (TAAR1) is a trace amine-associated receptor (TAAR) protein that in humans is encoded by the TAAR1 gene. TAAR1 is an intracellular amine-activated Gs-coupled and Gq-coupled G protein-coupled receptor (GPCR) that is primarily expressed in several peripheral organs and cells, astrocytes, and in the intracellular milieu within the presynaptic plasma membrane of monoamine neurons in the central nervous system (CNS). TAAR1 was discovered in 2001 by two independent groups of investigators, Borowski et al. and Bunzow et al. TAAR1 is one of six functional human trace amine-associated receptors, which are so named for their ability to bind endogenous amines that occur in tissues at trace concentrations. TAAR1 plays a significant role in regulating neurotransmission in dopamine, norepinephrine, and serotonin neurons in the CNS; it also affects immune system and neuroimmune system function through different mechanisms.
3-Methoxytyramine (3-MT), also known as 3-methoxy-4-hydroxyphenethylamine, is a human trace amine that occurs as a metabolite of the neurotransmitter dopamine. It is formed by the introduction of a methyl group to dopamine by the enzyme catechol-O-methyl transferase (COMT). 3-MT can be further metabolized by the enzyme monoamine oxidase (MAO) to form homovanillic acid (HVA), which is then typically excreted in the urine.
Amiflamine (FLA-336) is a reversible inhibitor of monoamine oxidase A (MAO-A), thereby being a RIMA, and, to a lesser extent, semicarbazide-sensitive amine oxidase (SSAO), as well as a serotonin releasing agent (SRA). It is a derivative of the phenethylamine and amphetamine chemical classes. The (+)-enantiomer is the active stereoisomer.
meta-Tyramine, also known as m-tyramine and 3-tyramine, is an endogenous trace amine neuromodulator and a structural analog of phenethylamine. It is a positional isomer of para-tyramine, and similarly to it, has effects on the adrenergic and dopaminergic systems.
N-Methyltyramine (NMT), also known as 4-hydroxy-N-methylphenethylamine, is a human trace amine and natural phenethylamine alkaloid found in a variety of plants. As the name implies, it is the N-methyl analog of tyramine, which is a well-known biogenic trace amine with which NMT shares many pharmacological properties. Biosynthetically, NMT is produced by the N-methylation of tyramine via the action of the enzyme phenylethanolamine N-methyltransferase in humans and tyramine N-methyltransferase in plants.
3,4-Dichloroamphetamine (DCA), is an amphetamine derived drug invented by Eli Lilly in the 1960s, which has a number of pharmacological actions. It acts as a highly potent and selective serotonin releasing agent (SSRA) and binds to the serotonin transporter with high affinity, but also acts as a selective serotonergic neurotoxin in a similar manner to the related para-chloroamphetamine, though with slightly lower potency. It is also a monoamine oxidase inhibitor (MAOI), as well as a very potent inhibitor of the enzyme phenylethanolamine N-methyl transferase which normally functions to transform noradrenaline into adrenaline in the body.
RO-5166017 is a drug developed by Hoffmann-La Roche which acts as a potent and selective agonist for the trace amine-associated receptor 1, with no significant activity at other targets. This is important for the study of the TAAR1 receptor, as while numerous other compounds are known which act as TAAR1 agonists, such as methamphetamine, MDMA and 3-iodothyronamine, all previously known TAAR1 agonists are either weak and rapidly metabolized, or have strong pharmacological activity at other targets, making it very difficult to assess which effects are due to TAAR1 activation. The discovery of RO-5166017 allows purely TAAR1 mediated effects to be studied, and in animal studies it was shown to prevent stress-induced hyperthermia and block dopamine-dependent hyperlocomotion, as well as blocking the hyperactivity which would normally be induced by an NMDA antagonist. The experiment was done in dopamine transporter knockout mice, and since TAAR1 affects the dopamine transporter, the results could be very different in humans.
2-Methylphenethylamine (2MPEA) is an organic compound with the chemical formula of C9H13N. 2MPEA is a human trace amine associated receptor 1 (TAAR1) agonist, a property which it shares with its monomethylated phenethylamine isomers, such as amphetamine (α-methylphenethylamine), β-methylphenethylamine, and N-methylphenethylamine.
3-Methylphenethylamine (3MPEA) is an organic compound with the chemical formula of C9H13N. 3MPEA is a human trace amine associated receptor 1 (TAAR1) agonist, a property which it shares with its monomethylated phenethylamine isomers, such as amphetamine (α-methylphenethylamine), β-methylphenethylamine, and N-methylphenethylamine.
