A monoamine neurotoxin, or monoaminergic neurotoxin, is a drug that selectively damages or destroys monoaminergic neurons. [1] Monoaminergic neurons are neurons that signal via stimulation by monoamine neurotransmitters including serotonin, dopamine, and norepinephrine. [1]
Examples of monoamine neurotoxins include the serotonergic neurotoxins para-chloroamphetamine (PCA), methylenedioxymethamphetamine (MDMA), and 5,7-dihydroxytryptamine (5,7-DHT); [2] the dopaminergic neurotoxins oxidopamine (6-hydroxydopamine), MPTP, and methamphetamine; and the noradrenergic neurotoxins oxidopamine and DSP-4. [1]
Dopaminergic neurotoxins can induce a Parkinson's disease-like condition in animals and humans. [1] [3] Serotonergic neurotoxins have been associated with cognitive and memory deficits and psychiatric changes. [4] [5] [6] [7]
Empathogens or entactogens are a class of psychoactive drugs that induce the production of experiences of emotional communion, oneness, relatedness, emotional openness—that is, empathy or sympathy—as particularly observed and reported for experiences with 3,4-methylenedioxymethamphetamine (MDMA). This class of drug is distinguished from the classes of hallucinogen or psychedelic, and amphetamine or stimulants. Major members of this class include MDMA, MDA, MDEA, MDOH, MBDB, 5-APB, 5-MAPB, 6-APB, 6-MAPB, methylone, mephedrone, GHB, αMT, and αET, MDAI among others. Most entactogens are phenethylamines and amphetamines, although several, such as αMT and αET, are tryptamines. When referring to MDMA and its counterparts, the term MDxx is often used. Entactogens are sometimes incorrectly referred to as hallucinogens or stimulants, although many entactogens such as ecstasy exhibit psychedelic or stimulant properties as well.
MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) is an organic compound. It is classified as a tetrahydropyridine. It is of interest as a precursor to the monoaminergic neurotoxin MPP+, which causes permanent symptoms of Parkinson's disease by destroying dopaminergic neurons in the substantia nigra of the brain. It has been used to study disease models in various animals.
Dopaminergic means "related to dopamine", a common neurotransmitter. Dopaminergic substances or actions increase dopamine-related activity in the brain.
Oxidopamine, also known as 6-hydroxydopamine (6-OHDA) or 2,4,5-trihydroxyphenethylamine, is a synthetic monoaminergic neurotoxin used by researchers to selectively destroy dopaminergic and noradrenergic neurons in the brain.
5,7-Dihydroxytryptamine (5,7-DHT) is a monoaminergic neurotoxin used in scientific research to decrease concentrations of serotonin in the brain. The mechanism behind this effect is not well understood, but it is speculated to selectively destroy serotonergic neurons, in a manner similar to the dopaminergic neurotoxicity of 6-hydroxydopamine (6-OHDA). What is known is that this compound is in fact not selective in depleting serotonin content, but also depletes norepinephrine. To selectively deplete serotonin stores, it is commonly administered in conjunction with desmethylimipramine (desipramine), which inhibits the norepinephrine transporter.
para-Chloroamphetamine (PCA), also known as 4-chloroamphetamine (4-CA), is a substituted amphetamine and monoamine releaser similar to MDMA, but with substantially higher activity as a monoaminergic neurotoxin, thought to be due to the unrestrained release of both serotonin and dopamine by a metabolite. It is used as a neurotoxin by neurobiologists to selectively kill serotonergic neurons for research purposes, in the same way that 6-hydroxydopamine is used to kill dopaminergic neurons.
MDAI, also known as 5,6-methylenedioxy-2-aminoindane, is an entactogen drug of the 2-aminoindane group which is related to MDMA and produces similar subjective effects.
A monoamine releasing agent (MRA), or simply monoamine releaser, is a drug that induces the release of one or more monoamine neurotransmitters from the presynaptic neuron into the synapse, leading to an increase in the extracellular concentrations of the neurotransmitters and hence enhanced signaling by those neurotransmitters. The monoamine neurotransmitters include serotonin, norepinephrine, and dopamine; monoamine releasing agents can induce the release of one or more of these neurotransmitters.
UWA-101 is a phenethylamine derivative researched as a potential treatment for Parkinson's disease. Its chemical structure is very similar to that of the illegal drug MDMA, the only difference being the replacement of the α-methyl group with an α-cyclopropyl group. MDMA has been found in animal studies and reported in unauthorised human self-experiments to be effective in the short-term relief of side-effects of Parkinson's disease therapy, most notably levodopa-induced dyskinesia. However the illegal status of MDMA and concerns about its potential for recreational use, neurotoxicity and potentially dangerous side effects mean that it is unlikely to be investigated for medical use in this application, and so alternative analogues were investigated.
5-MAPB, or 5-MBPB, also known as 1-(benzofuran-5-yl)-N-methylpropan-2-amine, is an entactogenic designer drug similar to MDMA in its structure and effects.
2,4,5-Trihydroxymethamphetamine (THMA) is a neurotoxin and a metabolite of MDMA. It has structural similarity to the dopamine neurotoxin 6-hydroxydopamine, and produces lasting serotonin deficits when administered centrally.
Animal models of Parkinson's disease are essential in the research field and widely used to study Parkinson's disease. Parkinson's disease is a neurodegenerative disorder, characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). The loss of the dopamine neurons in the brain, results in motor dysfunction, ultimately causing the four cardinal symptoms of PD: tremor, rigidity, postural instability, and bradykinesia. It is the second most prevalent neurodegenerative disease, following Alzheimer's disease. It is estimated that nearly one million people could be living with PD in the United States.
HPP+, also known as haloperidol pyridinium, is a monoaminergic neurotoxin and a metabolite of haloperidol.
5,6-Dihydroxytryptamine (5,6-DHT) is a monoaminergic neurotoxin and tryptamine derivative related to serotonin (5-hydroxytryptamine) and 5,7-dihydroxytryptamine (5,7-DHT). It is a relatively selective serotonergic neurotoxin, but also acts as a dopaminergic and noradrenergic neurotoxin at higher doses. In addition, it produces widespread generalized toxicity at higher doses. Its selective serotonergic neurotoxicity is due to its high affinity for the serotonin transporter (SERT). Because of its SERT affinity, 5,6-DHT has activity as a serotonin reuptake inhibitor.
ODMA is a bioisosteric analogue of 3,4-methylenedioxy-N-methylamphetamine (MDMA) which was developed in an attempt to create an improved MDMA alternative for potential clinical use. It is the analogue of MDMA in which the 1,3-benzodioxole ring has been replaced with a 2,1,3-benzoxadiazole ring. TDMA and SeDMA are closely related analogues. ODMA, TDMA, and SeDMA are releasing agents of serotonin, norepinephrine, and dopamine similarly to MDMA. However, they are less potent and efficacious in activating the serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptors than MDMA and show differing and potentially improved metabolic and pharmacokinetic properties in comparison. ODMA, TDMA, and SeDMA were first described in the scientific literature in June 2024.
TDMA is a bioisosteric analogue of 3,4-methylenedioxy-N-methylamphetamine (MDMA) which was developed in an attempt to create an improved MDMA alternative for potential clinical use. It is the analogue of MDMA in which the 1,3-benzodioxole ring has been replaced with a 2,1,3-benzothiadiazole ring. ODMA and SeDMA are closely related analogues. ODMA, TDMA, and SeDMA are releasing agents of serotonin, norepinephrine, and dopamine similarly to MDMA. However, they are less potent and efficacious in activating the serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptors than MDMA and show differing and potentially improved metabolic and pharmacokinetic properties in comparison. ODMA, TDMA, and SeDMA were first described in the scientific literature in June 2024.
SeDMA is a bioisosteric analogue of 3,4-methylenedioxy-N-methylamphetamine (MDMA) which was developed in an attempt to create an improved MDMA alternative for potential clinical use. It is the analogue of MDMA in which the 1,3-benzodioxole ring has been replaced with a 2,1,3-benzoselenadiazole ring. ODMA and TDMA are closely related analogues. ODMA, TDMA, and SeDMA are releasing agents of serotonin, norepinephrine, and dopamine similarly to MDMA. However, they are less potent and efficacious in activating the serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptors than MDMA and show differing and potentially improved metabolic and pharmacokinetic properties in comparison. ODMA, TDMA, and SeDMA were first described in the scientific literature in June 2024.
2′-NH2-MPTP, also known as 2′-amino-MPTP, is a monoaminergic neurotoxin that was derived from MPTP and is used in scientific research to lesion brain monoaminergic systems in animals. Whereas MPTP is a selective dopaminergic neurotoxin, 2′-NH2-MPTP is a specific serotonergic and noradrenergic neurotoxin that does not affect dopaminergic neurons. 2′-NH2-MPTP is transported by the serotonin transporter (SERT) into serotonergic neurons and by the norepinephrine transporter (NET) into noradrenergic neurons, and its serotonergic and noradrenergic neurotoxicity is dependent on this transport by the SERT and NET, respectively. 2′-NH2-MPTP was first described in the scientific literature by 1993.
2′-CH3-MPTP, also known as 2′-methyl-MPTP, is a selective dopaminergic neurotoxin related to MPTP which is used in scientific research to lesion dopaminergic neurons. It is a considerably more potent dopaminergic neurotoxin than MPTP in mice but is less potent than MPTP in primates. MPTP and 2′-CH3-MPTP produce a Parkinson's disease-like condition in animals.
HPTP is a monoaminergic neurotoxin related to MPTP. It is the dehydration product of haloperidol. The agent is specifically a dopaminergic and serotonergic neurotoxin. HPTP is a prodrug of HPP+, which mediates its monoaminergic neurotoxicity. This is analogous to how MPP+ mediates the neurotoxicity of MPTP. Other related compounds include RHPTP and RHPP+.
5-MAPB has been marketed as a less neurotoxic analogue of MDMA, but no studies have addressed whether 5-MAPB can cause the long lasting serotonergic changes seen with high or repeated MDMA dosing. [...] Neurochemical analyses indicated a statistically significant reduction in 5‑HT and 5-HIAA in all brain regions assessed 24 hours and two weeks after 6 mg/kg 5‑MAPB, with no statistically significant differences in monoamine levels between 1.2 mg/kg and saline-treated rats. There were also non-significant trends for reductions in striatal dopamine at both time intervals after 6 mg/kg 5-MAPB. These results show that 5-MAPB can dose-dependently produce persistent changes in 5-HT and 5-HIAA that appear analogous to those produced by MDMA.
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ignored (help)Ironically, in the 1960s, MPP+ itself had been tested as an herbicide under the commercial name of cyperquat (Di Monte, 2001).
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