This article needs additional citations for verification .(January 2015) |
A monoamine releasing agent (MRA), or simply monoamine releaser, is a drug that induces the release of a monoamine neurotransmitter from the presynaptic neuron into the synapse, leading to an increase in the extracellular concentrations of the neurotransmitter. Many drugs induce their effects in the body and/or brain via the release of monoamine neurotransmitters, e.g., trace amines, many substituted amphetamines, and related compounds.
MRAS can be classified by the monoamines they mainly release, although these drugs lie on a spectrum.
MRAs cause the release of monoamine neurotransmitters by various complex mechanism of actions. They may enter the presynaptic neuron primarily via plasma membrane transporters, such as the dopamine transporter (DAT), norepinephrine transporter (NET), and serotonin transporter (SERT). Some, such as exogenous phenethylamine, amphetamine, and methamphetamine, can also diffuse directly across the cell membrane to varying degrees. Once inside the presynaptic neuron, they may inhibit the reuptake of monoamine neurotransmitters through vesicular monoamine transporter 2 (VMAT2) and release the neurotransmitters stores of synaptic vesicles into the cytoplasm by inducing reverse transport at VMAT2. MRAs can also bind to the intracellular receptor TAAR1 as agonists, which triggers a phosphorylation cascade via protein kinases that results in the phosphorylation of monoamine transporters located at the plasma membrane (i.e., the dopamine transporter, norepinephrine transporter, and serotonin transporter); upon phosphorylation, these transporters transport monoamines in reverse (i.e., they move monoamines from the neuronal cytoplasm into the synaptic cleft). [1] The combined effects of MRAs at VMAT2 and TAAR1 result in the release of neurotransmitters out of synaptic vesicles and the cell cytoplasm into the synaptic cleft where they bind to their associated presynaptic autoreceptors and postsynaptic receptors. Certain MRAs interact with other presynaptic intracellular receptors which promote monoamine neurotransmission as well (e.g., methamphetamine is also an agonist at σ1 receptor).
Monoamine releasing agents can have a wide variety of effects depending upon their selectivity for monoamines. Selective serotonin releasing agents such as fenfluramine and related compounds are described as dysphoric and lethargic in lower doses, and in higher doses some hallucinogenic effects have been reported. [2] [3] Less selective serotonergic agents that stimulate an efflux in dopamine, such as MDMA are described as more pleasant, increasing energy, sociability and elevating mood. [4] Dopamine releasing agents, usually selective for both norepinephrine and dopamine have psychostimulant effect, causing an increase in energy, and elevated mood. [5] Other variables can significantly affect the subjective effects, such as infusion rate(increasing positive effects of cocaine), and expectancy. [6] Selectively noradrenergic drugs are minimally psychoactive, but as demonstrated by ephedrine may be distinguished from placebo, and trends towards liking. [7] They may also be ergogenic, [8] in contrast to reboxetine which is solely a reuptake inhibitor. [9] [10]
MRAs act to varying extents on serotonin, norepinephrine, and dopamine. Some induce the release of all three neurotransmitters to a similar degree, like MDMA, while others are more selective. As examples, amphetamine and methamphetamine are NDRAs but only very weak releasers of serotonin (~60- and 30-fold less than dopamine, respectively) and MBDB is a fairly balanced SNRA but a weak releaser of dopamine (~6- and 10-fold lower for dopamine than norepinephrine or serotonin, respectively). Even more selective include agents like fenfluramine, a selective SRA, and ephedrine, a selective NRA. The differences in selectivity of these agents is the result of different affinities as substrates for the monoamine transporters, and thus differing ability to gain access into monoaminergic neurons and induce monoamine neurotransmitter release via the TAAR1 and VMAT2 proteins.
As of present, no selective DRAs are known. This is because it has proven extremely difficult to separate DAT affinity from NET affinity and retain releasing efficacy at the same time. [11] Several selective SDRAs are known however, though these compounds also act as non-selective serotonin receptor agonists. [12]
Compound | 5-HT | NE | DA | Type | Class | Ref |
---|---|---|---|---|---|---|
2C-E | >100000 | >100000 | >100000 | IA | Phenethylamine | [15] |
2C-I | >100000 | >100000 | >100000 | IA | Phenethylamine | [15] |
3-Chloromethcathinone | ND | ND | 46.8 | ND | Cathinone | [16] |
3-Fluoroamphetamine | 1937 | 16.1 | 24.2 | NDRA | Amphetamine | [17] |
3-Methylamphetamine | 218 | 18.3 | 33.3 | NDRA | Amphetamine | [17] |
4-Fluoroamphetamine | 730–939 | 28.0–37 | 51.5–200 | NDRA | Amphetamine | [17] [15] |
cis-4-Methylaminorex | 53.2 | 4.8 | 1.7 | NDRA | Aminorex | [18] |
4-Methylamphetamine | 53.4 | 22.2 | 44.1 | SNDRA | Amphetamine | [17] |
4-Methylphenethylamine | ND | ND | 271 | ND | Phenethylamine | [16] |
4-Methylthiomethamphetamine | 21 | ND | ND | ND | Amphetamine | [19] |
4,4'-Dimethylaminorex | ND | ND | ND | SNDRA | Aminorex | ND |
''cis''-4,4'-Dimethylaminorex | 17.7–18.5 | 11.8–26.9 | 8.6–10.9 | SNDRA | Aminorex | [18] [20] |
''trans''-4,4'-Dimethylaminorex | 59.9 | 31.6 | 24.4 | SNDRA | Aminorex | [20] |
5-(2-Aminopropyl)indole | 28–104.8 | 13.3–79 | 12.9–173 | SNDRA | Amphetamine | [12] [21] |
(''R'')-5-(2-Aminopropyl)indole | 177 | 81 | 1062 | SNRA | Amphetamine | [12] |
(''S'')-5-(2-Aminopropyl)indole | ND | ND | ND | SNDRA | Amphetamine | ND |
5-Chloro-αMT | 16 | 3434 | 54 | SDRA | Tryptamine | [12] |
5-Fluoro-αMT | 19 | 126 | 32 | SNDRA | Tryptamine | [12] |
5-MeO-αMT | 460 | 8900 | 1500 | SNDRA | Tryptamine | [15] |
5-MeO-DMT | >100000 | >100000 | >100000 | IA | Tryptamine | [15] |
6-(2-Aminopropyl)indole | 19.9 | 25.6 | 164.0 | SNDRA | Amphetamine | [21] |
Adderall | ND | ND | ND | NDRA | Amphetamine | ND |
α-Methyltryptamine | 68 | 79 | 180 | SNDRA | Tryptamine | [15] |
Amfepramone (diethylpropion) | >10000 | >10000 | >10000 | PD | Cathinone | [22] |
Aminorex | 193–414 | 15.1–26.4 | 9.1–49.4 | SNDRA | Aminorex | [23] [18] |
Amphetamine | ND | ND | ND | NDRA | Amphetamine | ND |
D-Amphetamine | 698–1765 | 6.6–7.2 | 5.8–24.8 | NDRA | Amphetamine | [23] [24] |
L-Amphetamine | ND | ND | ND | NRA | Amphetamine | ND |
β-Ketophenethylamine | ND | ND | 208 | ND | Phenethylamine | [16] |
BDB | 180 | 540 | 2,300 | NDRA | Amphetamine | [15] |
Benzylpiperazine | ≥6050 | 62–68 | 175–600 | NDRA | Arylpiperazine | [15] [25] [14] |
Butylamphetamine | ND | ND | IA | ND | Amphetamine | [16] |
Cathinone | ND | ND | ND | NDRA | Cathinone | ND |
D-Cathinone | ND | ND | ND | NRA | Cathinone | ND |
L-Cathinone | 2366 | 12.4 | 18.5 | NDRA | Cathinone | [26] |
Chlorphentermine | 30.9 | >10000 | 2650 | SRA | Amphetamine | [23] |
DMPP | 26 | 56 | 1207 | SNRA | Arylpiperazine | [19] |
Dopamine | >10000 | 66.2 | 86.9 | NDRA | Phenethylamine | [23] |
DPT | >100000 | >100000 | >100000 | IA | Tryptamine | [15] |
Ephedrine | ND | ND | ND | NDRA | Cathinol | ND |
D-Ephedrine | >10000 | 43.1–72.4 | 236–1350 | NDRA | Cathinol | [23] |
L-Ephedrine | >10000 | 218 | 2104 | NRA | Cathinol | [23] [26] |
Epinephrine | ND | ND | ND | NDRA | Phenethylamine | ND |
Ethcathinone | 2118 | 99.3 | >1000 | NRA | Cathinone | [22] |
Ethylamphetamine | ND | ND | 296 | ND | Amphetamine | [16] |
Fenfluramine | 79.3–108 | 739 | >10000 | SRA | Amphetamine | [23] [27] [28] |
D-Fenfluramine | 51.7 | 302 | >10000 | SNRA | Amphetamine | [23] [27] |
L-Fenfluramine | 147 | >10000 | >10000 | SRA | Amphetamine | [27] [29] |
MBDB | 540 | 3300 | >100,000 | SNRA | Amphetamine | [15] |
mCPP | 28–38.1 | ≥1400 | 63000 | SRA | Arylpiperazine | [15] [29] [30] |
MDA | 160 | 108 | 190 | SNDRA | Amphetamine | [28] |
(''R'')-MDA | 310 | 290 | 900 | SNDRA | Amphetamine | [28] |
(''S'')-MDA | 100 | 50 | 98 | SNDRA | Amphetamine | [28] |
MDEA | 47 | 2608 | 622 | SNDRA | Amphetamine | [19] |
(''R'')-MDEA | 52 | 651 | 507 | SNDRA | Amphetamine | [19] |
(''S'')-MDEA | 465 | RI | RI | SRA | Amphetamine | [19] |
MDMA | 49.6–72 | 54.1–110 | 51.2–278 | SNDRA | Amphetamine | [23] [31] [21] [28] |
(''R'')-MDMA | 340 | 560 | 3700 | SNDRA | Amphetamine | [28] |
(''S'')-MDMA | 74 | 136 | 142 | SNDRA | Amphetamine | [28] |
MDMAR | ND | ND | ND | SNDRA | Aminorex | ND |
''cis''-MDMAR | 43.9 | 14.8 | 10.2 | SNDRA | Aminorex | [20] |
''trans''-MDMAR | 73.4 | 38.9 | 36.2 | SNDRA | Aminorex | [20] |
Mephedrone | 118.3–122 | 58–62.7 | 49.1–51 | SNDRA | Cathinone | [31] [24] |
Methamnetamine | 13 | 34 | 10 | SNDRA | Amphetamine | [19] |
Methamphetamine | ND | ND | ND | NDRA | Amphetamine | ND |
D-Methamphetamine | 736–1291.7 | 12.3–13.8 | 8.5–24.5 | NDRA | Amphetamine | [23] [31] |
L-Methamphetamine | 4640 | 28.5 | 416 | NRA | Amphetamine | [23] |
Methcathinone | ND | ND | ND | NDRA | Cathinone | ND |
D-Methcathinone | ND | ND | ND | NRA | Cathinone | ND |
L-Methcathinone | 1772 | 13.1 | 14.8 | NDRA | Cathinone | [26] |
Methylone | 234–242.1 | 140–152.3 | 117–133.0 | SNDRA | Cathinone | [31] [24] |
Naphthylisopropylamine | 3.4 | 11.1 | 12.6 | SNDRA | Amphetamine | [32] |
Norephedrine | ND | ND | ND | NDRA | Cathinol | ND |
D-Norephedrine | >10000 | 42.1 | 302 | NDRA | Cathinol | [26] |
L-Norephedrine (phenylpropanolamine) | >10000 | 137 | 1371 | NRA | Cathinol | [26] |
Norepinephrine | >10000 | 164 | 869 | NDRA | Phenethylamine | [23] |
Norfenfluramine | 104 | 168–170 | 1900–1925 | SNRA | Amphetamine | [27] [28] |
Norpropylhexedrine | ND | ND | ND | NDRA | Cyclohexethylamine | ND |
D-Norpropylhexedrine | ND | ND | ND | NRA | Cyclohexethylamine | ND |
L-Norpropylhexedrine | ND | ND | ND | NDRA | Cyclohexethylamine | ND |
Norpseudoephedrine | ND | ND | ND | NDRA | Cathinol | ND |
D-Norpseudoephedrine (cathine) | >10000 | 15.0 | 68.3 | NDRA | Cathinol | [26] |
L-Norpseudoephedrine | >10000 | 30.1 | 294 | NDRA | Cathinol | [26] |
oMPP | 175 | 39.1 | 296–542 | SNDRA | Arylpiperazine | [33] [16] |
PAL-738 | 23 | 65 | 58 | SNDRA | Phenylmorpholine | [19] |
Phenethylamine | ND | ND | 39.5 | NDRA | Phenethylamine | [16] |
Phendimetrazine | >100000 | >10000 | >10000 | PD | Phenylmorpholine | [34] |
Phenmetrazine | 7765 | 50.4 | 131 | NDRA | Phenylmorpholine | [34] |
Phentermine | 3511 | 39.4 | 262 | NDRA | Amphetamine | [23] |
Phenylalaninol | ND | ND | ND | ND | Amphetamine | ND |
D-Phenylalaninol | >10000 | 106 | 1355 | NRA | Amphetamine | [33] |
L-Phenylalaninol | ND | ND | ND | ND | Amphetamine | ND |
Phenylisobutylamine | ND | ND | 225 | ND | Amphetamine | [16] |
pMPP | 3200 | 1500 | 11000 | SNRA | Arylpiperazine | [15] |
pNPP | 43 | >10000 | >10000 | SRA | Arylpiperazine | [19] |
Propylamphetamine | ND | ND | RI (1013) | ND | Amphetamine | [16] |
Propylhexedrine | ND | ND | ND | NDRA | Cyclohexethylamine | ND |
D-Propylhexedrine | ND | ND | ND | NRA | Cyclohexethylamine | ND |
L-Propylhexedrine | ND | ND | ND | NDRA | Cyclohexethylamine | ND |
Pseudoephedrine | ND | ND | ND | NDRA | Cathinol | ND |
D-Pseudoephedrine | >10000 | 4092 | 9125 | NDRA | Cathinol | [26] |
L-Pseudoephedrine | >10000 | 224 | 1988 | NRA | Cathinol | [26] |
Pseudophenmetrazine | >10000 | 514 | RI | NRA | Phenylmorpholine | [34] |
Psilocin | 561 | >10000 | >10000 | SRA | Tryptamine | [19] |
Serotonin | 44.4 | >10000 | >10000 | SRA | Tryptamine | [23] |
TFMPP | 121 | ND | >10000 | SRA | Arylpiperazine | [25] |
TFMCPP | 33 | >10000 | >10000 | SRA | Arylpiperazine | [19] |
Trimethoxyamphetamine | 16000 | >100000 | >100000 | IA | Amphetamine | [15] |
Tyramine | 2775 | 40.6 | 119 | NDRA | Phenethylamine | [23] |
The smaller the value, the more strongly the substance activates or releases the neurotransmitter. | ||||||
A norepinephrine reuptake inhibitor or noradrenaline reuptake inhibitor or adrenergic reuptake inhibitor (ARI), is a type of drug that acts as a reuptake inhibitor for the neurotransmitters norepinephrine (noradrenaline) and epinephrine (adrenaline) by blocking the action of the norepinephrine transporter (NET). This in turn leads to increased extracellular concentrations of norepinephrine and epinephrine and therefore can increase adrenergic neurotransmission.
α-Ethyltryptamine, also known as etryptamine, is a psychedelic, stimulant, and entactogenic drug of the tryptamine class. It was originally developed and marketed as an antidepressant under the brand name Monase by Upjohn in the 1960s.
Fenfluramine, sold under the brand name Fintepla, is a serotonergic medication used for the treatment of seizures associated with Dravet syndrome and Lennox–Gastaut syndrome. It was formerly used as an appetite suppressant in the treatment of obesity, but was discontinued for this use due to cardiovascular toxicity before being repurposed for new indications. Fenfluramine was used for weight loss both alone under the brand name Pondimin and in combination with phentermine commonly known as fen-phen.
Etilamfetamine is a stimulant drug of the phenethylamine and amphetamine chemical classes. It was invented in the early 20th century and was subsequently used as an anorectic or appetite suppressant in the 1950s, but was not as commonly used as other amphetamines such as amphetamine, methamphetamine, and benzphetamine, and was largely discontinued once newer drugs such as phenmetrazine were introduced. It most likely acts primarily as a dopamine releasing agent. Its activity as a norepinephrine or serotonin releasing agent is not known.
Naphthylaminopropane (PAL-287) is an experimental drug under investigation as of 2007 for the treatment of alcohol and stimulant addiction.
5-Fluoro-α-methyltryptamine, also known as PAL-544, is a putative stimulant, entactogen, and psychedelic tryptamine derivative related to α-methyltryptamine (αMT). It has been found to act as a well-balanced serotonin-norepinephrine-dopamine releasing agent, a 5-HT2A receptor agonist, and a potent and specific MAO-A inhibitor. which suggests that 5-fluoro-αMT could be an active psychedelic in humans, although it is not known to have been tested in humans and could be dangerous due to its strong inhibition of MAO-A.
In pharmacology, an indirect agonist or indirect-acting agonist is a substance that enhances the release or action of an endogenous neurotransmitter but has no specific agonist activity at the neurotransmitter receptor itself. Indirect agonists work through varying mechanisms to achieve their effects, including transporter blockade, induction of transmitter release, and inhibition of transmitter breakdown.
Reuptake inhibitors (RIs) are a type of reuptake modulators. It is a drug that inhibits the plasmalemmal transporter-mediated reuptake of a neurotransmitter from the synapse into the pre-synaptic neuron. This leads to an increase in extracellular concentrations of the neurotransmitter and an increase in neurotransmission. Various drugs exert their psychological and physiological effects through reuptake inhibition, including many antidepressants and psychostimulants.
A serotonin releasing agent (SRA) is a type of drug that induces the release of serotonin into the neuronal synaptic cleft. A selective serotonin releasing agent (SSRA) is an SRA with less significant or no efficacy in producing neurotransmitter efflux at other types of monoamine neurons.
A serotonin–dopamine releasing agent (SDRA) is a type of drug which induces the release of serotonin and dopamine in the body and/or brain.
4-Methylamphetamine is a stimulant and anorectic drug of the phenethylamine and amphetamine chemical classes.
5-(2-Aminopropyl)indole is an indole and phenethylamine derivative with empathogenic effects. Its preparation was first reported by Albert Hofmann in 1962. It is a designer drug that has been openly sold as a recreational drug by online vendors since 2011.
3-Methylamphetamine is a stimulant drug from the amphetamine family. It is self-administered by mice to a similar extent to 4-fluoroamphetamine and has comparable properties as a monoamine releaser, although with a more balanced release of all three monoamines, as opposed to the more dopamine/noradrenaline selective fluoro analogues.
3-Fluoroamphetamine is a stimulant drug from the amphetamine family which acts as a monoamine releaser with similar potency to methamphetamine but more selectivity for dopamine and norepinephrine release over serotonin. It is self-administered by mice to a similar extent to related drugs such as 4-fluoroamphetamine and 3-methylamphetamine.
A serotonin–dopamine reuptake inhibitor (SDRI) is a type of drug which acts as a reuptake inhibitor of the monoamine neurotransmitters serotonin and dopamine by blocking the actions of the serotonin transporter (SERT) and dopamine transporter (DAT), respectively. This in turn leads to increased extracellular concentrations of serotonin and dopamine, and, therefore, an increase in serotonergic and dopaminergic neurotransmission.
A monoamine reuptake inhibitor (MRI) is a drug that acts as a reuptake inhibitor of one or more of the three major monoamine neurotransmitters serotonin, norepinephrine, and dopamine by blocking the action of one or more of the respective monoamine transporters (MATs), which include the serotonin transporter (SERT), norepinephrine transporter (NET), and dopamine transporter (DAT). This in turn results in an increase in the synaptic concentrations of one or more of these neurotransmitters and therefore an increase in monoaminergic neurotransmission.
Methamnetamine is a triple monoamine releasing agent and N-methyl analog of the non-neurotoxic experimental drug naphthylaminopropane and the naphthalene analog of methamphetamine. It has been sold online as a designer drug.
Substituted phenylmorpholines, or substituted phenmetrazines alternatively, are chemical derivatives of phenylmorpholine or of the psychostimulant drug phenmetrazine. Most such compounds act as releasers of monoamine neurotransmitters, and have stimulant effects. Some also act as agonists at serotonin receptors, and compounds with an N-propyl substitution act as dopamine receptor agonists. A number of derivatives from this class have been investigated for medical applications, such as for use as anorectics or medications for the treatment of ADHD. Some compounds have also become subject to illicit use as designer drugs.
PCP site 2 is a binding site that was identified as a high-affinity target for phencyclidine (PCP), an anesthetic and dissociative hallucinogen that acts primarily as an NMDA receptor antagonist. The site is distinct from the PCP binding site on the NMDA receptor and the common/main sites on the monoamine transporters. It is associated with monoamine reuptake inhibition, and it has been suggested that the site may be an allosteric/regulatory site of the monoamine transporters.
ortho-Methylphenylpiperazine (also known as oMPP, oMePP, 1-(2-methylphenyl)piperazine, 2-MPP, and 2-MePP) is a psychoactive designer drug of the phenylpiperazine group. It acts as a serotonin–norepinephrine–dopamine releasing agent (SNDRA), with EC50 values for induction of monoamine release of 175 nM for serotonin, 39.1 nM for norepinephrine, and 296–542 nM for dopamine. As such, it has about 4.5-fold preference for induction of norepinephrine release over serotonin, and about 7.6- to 13.9-fold preference for induction of norepinephrine release over dopamine.
{{cite book}}
: |author=
has generic name (help)