Phencyclidine or phenylcyclohexyl piperidine (PCP), also known in its use as a street drug as angel dust among other names, is a dissociative anesthetic mainly used recreationally for its significant mind-altering effects. PCP may cause hallucinations, distorted perceptions of sounds, and violent behavior. As a recreational drug, it is typically smoked, but may be taken by mouth, snorted, or injected. It may also be mixed with cannabis or tobacco.
Apomorphine, sold under the brand name Apokyn among others, is a type of aporphine having activity as a non-selective dopamine agonist which activates both D2-like and, to a much lesser extent, D1-like receptors. It also acts as an antagonist of 5-HT2 and α-adrenergic receptors with high affinity. The compound is an alkaloid belonging to nymphaea caerulea, or blue lotus, but is also historically known as a morphine decomposition product made by boiling morphine with concentrated acid, hence the -morphine suffix. Contrary to its name, apomorphine does not actually contain morphine or its skeleton, nor does it bind to opioid receptors. The apo- prefix relates to it being a morphine derivative ("[comes] from morphine").
A dopamine agonist is a compound that activates dopamine receptors. There are two families of dopamine receptors, D1-like and D2-like. They are all G protein-coupled receptors. D1- and D5-receptors belong to the D1-like family and the D2-like family includes D2, D3 and D4 receptors. Dopamine agonists are primarily used in the treatment of the motor symptoms of Parkinson's disease, and to a lesser extent, in hyperprolactinemia and restless legs syndrome. They are also used off-label in the treatment of clinical depression. Impulse control disorders are associated with the use of dopamine agonists for whatever condition.
Aporphine is an alkaloid with the chemical formula C17H17N. It is the core chemical substructure of the aporphine alkaloids, a subclass of quinoline alkaloids. It can exist in either of two enantiomeric forms, (R)-aporphine and (S)-aporphine.
Bulbocapnine is an alkaloid found in Corydalis and Dicentra, genera of the plant family Fumariaceae which have caused the fatal poisoning of sheep and cattle. It has been shown to act as an acetylcholinesterase inhibitor, and inhibits biosynthesis of dopamine via inhibition of the enzyme tyrosine hydroxylase. Like apomorphine, it is reported to be an inhibitor of amyloid beta protein (Aβ) fiber formation, whose presence is a hallmark of Alzheimer's disease (AD). Bulbocapnine is thus a potential therapeutic under the amyloid hypothesis. According to the Dorlands Medical Dictionary, it "inhibits the reflex and motor activities of striated muscle. It has been used in the treatment of muscular tremors and vestibular nystagmus".
NMDA receptor antagonists are a class of drugs that work to antagonize, or inhibit the action of, the N-Methyl-D-aspartate receptor (NMDAR). They are commonly used as anesthetics for humans and animals; the state of anesthesia they induce is referred to as dissociative anesthesia.
Molindone, sold under the brand name Moban, is an antipsychotic medication which is used in the United States in the treatment of schizophrenia. It is taken by mouth.
N-n-Propylnorapomorphine (NPA) is an aporphine derivative dopamine agonist closely related to apomorphine. In rodents it has been shown to produce hyperactivity, stereotypy, hypothermia, antinociception, and penile erection, among other effects. Notably, its effects on locomotion are biphasic, with low doses producing inhibition and catalepsy and high doses resulting in enhancement of activity. This is likely due to preferential activation of D2/D3 autoreceptors versus postsynaptic receptors, the latter of which overcomes the former to increase postsynaptic dopaminergic signaling only with high doses.
Glaucine is an aporphine alkaloid found in several different plant species in the family Papaveraceae, such as Glaucium flavum, Glaucium oxylobum, and Corydalis yanhusuo, and in other plants such as Croton lechleri in the family Euphorbiaceae.
(−)-Stepholidine is a protoberberine alkaloid found in the plant Stephania intermedia.
Nantenine is an alkaloid found in the plant Nandina domestica as well as some Corydalis species. It is an antagonist of both the α1-adrenergic receptor and the serotonin 5-HT2A receptor, and blocks both the behavioral and physiological effects of MDMA in animals.
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, including dopamine and norepinephrine neurons.
Sonepiprazole (U-101,387, PNU-101,387-G) is a drug of the phenylpiperazine class which acts as a highly selective D4 receptor antagonist. In animals, unlike D2 receptor antagonists like haloperidol, sonepiprazole does not block the behavioral effects of amphetamine or apomorphine, does not alter spontaneous locomotor activity on its own, and lacks extrapyramidal and neuroendocrine effects. However, it does reverse the prepulse inhibition deficits induced by apomorphine, and has also been shown to enhance cortical activity and inhibit stress-induced cognitive impairment. As a result, it was investigated as an antipsychotic for the treatment of schizophrenia in a placebo-controlled clinical trial, but in contrast to its comparator olanzapine no benefits were found and it was not researched further for this indication.
F-15,063 is an orally active potential antipsychotic, and an antagonist at the D2/D3 receptors, partial agonist at the D4 receptor, and agonist at the 5-HT1A receptors. It has greater efficacy at the 5-HT1A receptors than other antipsychotics, such as clozapine, aripiprazole, and ziprasidone. This greater efficacy may lead to enhanced antipsychotic properties, as antipsychotics that lack 5-HT1A affinity are associated with increased risk of extrapyramidal symptoms, and lack of activity against the negative symptoms of schizophrenia.
The head-twitch response (HTR), also sometimes known as wet dog shakes (WDS) in rats, is a rapid side-to-side head movement that occurs in mice and rats when the serotonin 5-HT2A receptor is activated. Serotonergic psychedelics, including lysergic acid diethylamide (LSD), induce the HTR, and so the HTR is widely used as an animal behavioral model of hallucinogen effects and to discover new psychedelic drugs. HTR-like effects are also induced by psychedelics in other animal species, for instance cats and stump-tailed macaque monkeys. Other related behaviors to head twitches induced by serotonergic agents include limb jerks and body scratches. The only other behavioral paradigms for assessment of psychedelic-like effects in animals are drug discrimination (DD), prepulse inhibition (PPI), and time perception.
Alstonine is a pentacyclic alkaloid and putative antipsychotic constituent of various plant species including Alstonia boonei, Catharanthus roseus, Picralima nitida, Rauvolfia afra and Rauvolfia vomitoria. In preclinical studies alstonine attenuates MK-801-induced hyperlocomotion, working memory deficit and social withdrawal. It also possesses anxiolytic-like effects in preclinical studies, attenuates amphetamine-induced lethality and stereotypy as well as apomorphine-induced stereotypy, and attenuates haloperidol-induced catalepsy. These effects appear to be mediated by stimulation of the 5-HT2C receptor. In addition, alstonine, similarly to clozapine, indirectly inhibits the reuptake of glutamate in hippocampal slices. Unlike clozapine however, the effect of which is abolished by the D2 receptor agonist apomorphine, alstonine requires 5-HT2A and 5-HT2C receptors to produce this effect, as it is abolished by antagonists of these receptors. Also unlike clozapine, alstonine lacks pro-convulsant activity in mice.
5-Chloro-α-methyltryptamine (5-Chloro-αMT), also known as PAL-542, is a tryptamine derivative related to α-methyltryptamine (αMT) and one of only a few known specific serotonin-dopamine releasing agents (SDRAs). It has been investigated in animals as a potential treatment for cocaine dependence. The EC50 values of 5-chloro-αMT in evoking the in vitro release of serotonin (5-HT), dopamine (DA), and norepinephrine (NE) in rat synaptosomes were reported as 16 nM, 54 nM, and 3434 nM, with an NE/DA ratio of 63.6 and a DA/5-HT ratio of 3.38, indicating that it is a highly specific and well-balanced SDRA. However, 5-chloro-αMT has also been found to act as a potent full agonist of the 5-HT2A receptor, with an EC50 value of 6.27 nM and an efficacy of 105%. It is likely to act as a potent agonist of other serotonin receptors as well.
Peripherally selective drugs have their primary mechanism of action outside of the central nervous system (CNS), usually because they are excluded from the CNS by the blood–brain barrier. By being excluded from the CNS, drugs may act on the rest of the body without producing side-effects related to their effects on the brain or spinal cord. For example, most opioids cause sedation when given at a sufficiently high dose, but peripherally selective opioids can act on the rest of the body without entering the brain and are less likely to cause sedation. These peripherally selective opioids can be used as antidiarrheals, for instance loperamide (Imodium).
Hyperlocomotion, also known as locomotor hyperactivity, hyperactivity, or increased locomotor activity, is an effect of certain drugs in animals in which locomotor activity (locomotion) is increased. It is induced by certain drugs like psychostimulants and NMDA receptor antagonists and is reversed by certain other drugs like antipsychotics and certain antidepressants. Stimulation of locomotor activity is thought to be mediated by increased signaling in the nucleus accumbens.
Aporphine alkaloids are naturally occurring chemical compounds from the group of alkaloids. After the benzylisoquinoline alkaloids they are the second largest group of isoquinoline alkaloids.
