Sigma agonists

Cocaine is a stimulant of the central nervous system and tropane alkaloid, derived primarily from the leaves of two coca species native to South America: Erythroxylum coca and E. novogranatense. The leaves are processed into cocaine paste, a crude mixture of coca alkaloids, from which cocaine base is isolated and then converted to cocaine hydrochloride. Although total synthesis is possible, it is complex and not used for production. Historically, cocaine was a standard topical medication used as a local anesthetic with intrinsic vasoconstrictor properties. However, its high abuse potential, ad

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Ketamine is a cyclohexanone-derived general anesthetic and NMDA receptor antagonist with analgesic and hallucinogenic properties, used medically for anesthesia, depression, and pain management. Ketamine exists as its two enantiomers, S- (esketamine) and R- (arketamine), and has antidepressant action likely involving other mechanisms in addition to NMDA antagonism.

Fluoxetine, sold under the brand name Prozac, among others, is an antidepressant medication of the selective serotonin reuptake inhibitor (SSRI) class used for the treatment of major depressive disorder, anxiety, obsessive–compulsive disorder (OCD), panic disorder, premenstrual dysphoric disorder, and bulimia nervosa. It is also approved for treatment of major depressive disorder in adolescents and children 8 years of age and over. It has also been used to treat premature ejaculation. Fluoxetine is taken by mouth.

Methylphenidate, sold under the brand name Ritalin and Concerta, among others, is a central nervous system (CNS) stimulant used in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy. It may be taken by mouth or applied to the skin, and different formulations have varying durations of effect. For ADHD, the effectiveness of methylphenidate is comparable to atomoxetine but modestly lower than amphetamine. However, methylphenidate is preferred as a first-line treatment in children, while amphetamine is preferred in adults. Methylphenidate reduces core ADHD symptoms and

Amitriptyline, formerly sold under the brand name Elavil among others, is a tricyclic antidepressant primarily used to treat major depressive disorder, and a variety of pain syndromes such as neuropathic pain, fibromyalgia, migraine and tension headaches. Due to the frequency and prominence of side effects, amitriptyline is generally considered a second-line therapy for these indications.

Dextromethorphan is a cough suppressant used in many cough and cold medicines. In 2022, the US Food and Drug Administration (FDA) approved the combination dextromethorphan/bupropion to serve as a rapid-acting antidepressant in people with major depressive disorder.

Dimethyltryptamine (DMT), also known as '''N,N-dimethyltryptamine (N,N-DMT'''), is a serotonergic hallucinogen and investigational drug of the tryptamine family that occurs naturally in many plants and animals. DMT is used as a psychedelic drug and prepared by various cultures for ritual purposes as an entheogen.

Citalopram, sold under the brand name Celexa among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is used to treat major depressive disorder, obsessive compulsive disorder, panic disorder, and social phobia. The antidepressant effects may take one to four weeks to occur. It is typically taken orally (swallowed by mouth). In some European countries, it is sometimes given intravenously (injected into a vein) to initiate treatment, before switching to the oral route of administration for continuation of treatment. It has also been used intravenously in

Escitalopram ( ), sold under the brand names Lexapro and Cipralex, among others, is an antidepressant medication of the selective serotonin reuptake inhibitor (SSRI) class. It is mainly used to treat major depressive disorder, generalized anxiety disorder, panic disorder, obsessive–compulsive disorder (OCD), and social anxiety disorder. Escitalopram is taken by mouth. For commercial use, it is formulated as an oxalate salt exclusively.

Donepezil, sold under the brand name Aricept among others, is a medication used to treat dementia of the Alzheimer's type. It appears to result in a small benefit in mental function and ability to function. Use, however, has not been shown to change the progression of the disease. Treatment should be stopped if no benefit is seen. It is taken by mouth or via a transdermal patch.

Amantadine, sold under the brand name Gocovri among others, is a medication used to treat dyskinesia associated with parkinsonism and influenza caused by type A influenzavirus, though its use for the latter is no longer recommended because of widespread drug resistance. It is also used for a variety of other conditions. The drug is taken by mouth.

Venlafaxine, sold under the brand name Effexor among others, is an antidepressant medication of the serotonin–norepinephrine reuptake inhibitor (SNRI) class. It is used to treat major depressive disorder, generalized anxiety disorder, panic disorder, and social anxiety disorder. Studies have shown that venlafaxine improves post-traumatic stress disorder (PTSD) as a recommended first-line treatment. It may also be used for chronic neuropathic pain. It is taken orally (swallowed by mouth). It is also available as the salt venlafaxine besylate (venlafaxine benzenesulfonate monohydrate) in an exte

Memantine, sold under the brand name Namenda among others, is a medication used to slow the progression of moderate-to-severe Alzheimer's disease. It is taken by mouth.

Fluvoxamine, sold under the brand name Luvox among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is primarily used to treat major depressive disorder and, perhaps more-especially, obsessive–compulsive disorder (OCD), but is also used to treat anxiety disorders such as panic disorder, social anxiety disorder, and post-traumatic stress disorder.

Dehydroepiandrosterone (DHEA), also known as androstenolone, is an endogenous steroid hormone precursor. It is one of the most abundant circulating steroids in humans. DHEA is produced in the adrenal glands, the gonads, and the brain. It functions as a metabolic intermediate in the biosynthesis of the androgen and estrogen sex steroids both in the gonads and in various other tissues. However, DHEA also has a variety of potential biological effects in its own right, binding to an array of nuclear and cell surface receptors, and acting as a neurosteroid and modulator of neurotrophic factor recep

Ibogaine is a psychoactive indole alkaloid derived from plants such as Tabernanthe iboga, characterized by hallucinogenic and oneirogenic effects. Traditionally used by Central African foragers, it has undergone controversial research for the treatment of substance use disorders. Ibogaine exhibits complex pharmacology by interacting with multiple neurotransmitter systems, notably affecting opioid, serotonin, sigma, and NMDA receptors, while its metabolite noribogaine primarily acts as a serotonin reuptake inhibitor and κ-opioid receptor agonist.

Pregnenolone (P5), or pregn-5-en-3β-ol-20-one, is an endogenous steroid and precursor/metabolic intermediate in the biosynthesis of most of the steroid hormones, including the progestogens, androgens, estrogens, glucocorticoids, and mineralocorticoids. In addition, pregnenolone is biologically active in its own right, acting as a neurosteroid.

Noscapine, also known as narcotine, nectodon, nospen, anarcotine and (archaic) opiane, is a benzylisoquinoline alkaloid of the phthalideisoquinoline structural subgroup, which has been isolated from numerous species of the Papaveraceae (poppy) family. It lacks effects associated with opioids such as sedation, euphoria, or analgesia (pain-relief) and lacks addictive potential. Noscapine is primarily used for its antitussive (cough-suppressing) effects.

Pentazocine, sold under the brand name Talwin among others, is an analgesic medication used to treat moderate to severe pain. It is believed to work by activating (agonizing) κ-opioid receptors (KOR) and μ-opioid receptors (MOR). As such it is called an opioid as it delivers its effects on pain by interacting with the opioid receptors. It shares many of the side effects of other opioids like constipation, nausea, itching, drowsiness, and respiratory depression, but, unlike most other opioids, it fairly frequently causes hallucinations, nightmares, and delusions. It is also, unlike most other o

Butamirate (or brospamin, trade names Acodeen, Codesin, Pertix, Sinecod, Sinecoden, Sinecodix) is a cough suppressant. It has been marketed in Europe and Mexico, but not in the United States.

Opipramol, sold under the brand name Insidon among others, is an anxiolytic and tricyclic antidepressant that is used throughout Europe. Despite chemically being a tricyclic dibenzazepine (iminostilbene) derivative similar to imipramine, opipramol is not a monoamine reuptake inhibitor like most other tricyclic antidepressants, and instead acts primarily as a sigma-1 receptor agonist. It was developed by Schindler and Blattner in 1961.

Dextrorphan (DXO) is a psychoactive drug of the morphinan class which acts as an antitussive or cough suppressant and in high doses a dissociative hallucinogen. It is the dextrorotatory enantiomer of racemorphan; the levorotatory enantiomer is levorphanol. Dextrorphan is produced by O-demethylation of dextromethorphan by CYP2D6. Dextrorphan is an NMDA antagonist and contributes to the psychoactive effects of dextromethorphan.

chemical compound

Ifenprodil, sold under the brand names Cerocral, Dilvax, and Vadilex, is a cerebral vasodilator that has been marketed in some countries, including in Japan, Hong Kong, and France. It is currently under development for treatment of a variety of additional indications.

thumb|Afobazole from Russia

Racemorphan, or morphanol, is the racemic mixture of the two stereoisomers of 17-methylmorphinan-3-ol, each with differing pharmacology and effects:

Captodiame (INN), also known as captodiamine, is an antihistamine sold under the trade names Covatine, Covatix, and Suvren which is used as a sedative and anxiolytic. The structure is related to diphenhydramine.

4-PPBP is a neuroprotective cyclic amine which binds to sigma receptors.

Cutamesine (SA 4503) is a synthetic sigma receptor agonist which is selective for the σ1 receptor, a chaperone protein mainly found in the endoplasmic reticulum of cells in the central nervous system. These σ1 receptors play a key role in the modulation of Ca2+ release and apoptosis. Cutamesine's activation of the σ1 receptor is tied to a variety of physiological phenomena in the CNS, including activation of dopamine-releasing neurons and repression of the MAPK/ERK pathway.

Pentoxyverine (rINN) or carbetapentane is an antitussive (cough suppressant) commonly used for cough associated with illnesses like common cold. It is sold over-the-counter as Solotuss, or in combination with other medications, especially decongestants. One such product is Certuss, a combination of guaifenesin and pentoxyverine. The drug has been available in the form of drops, suspensions and suppositories.

Siramesine (or Lu 28-179) is a sigma receptor agonist, selective for the σ2 subtype. In animal studies, siramesine has been shown to produce anxiolytic and antidepressant effects. It was developed by the pharmaceutical company H Lundbeck for the treatment of anxiety, although development was discontinued after clinical trials showed a lack of efficacy in humans. Siramesine has been shown to produce an enhanced antidepressant effect when co-administered with NMDA antagonists. It has also been used to study the σ2 activity of cocaine, and has been shown to produce anticancer properties both in v

chemical compound

Tenocyclidine (TCP) is a dissociative anesthetic with psychostimulant effects. It was discovered by a team at Parke-Davis in the late 1950s. It is similar in effects to phencyclidine (PCP) but is considerably more potent. TCP has slightly different binding properties to PCP, with more affinity for the NMDA receptors, but less affinity for the sigma receptors. Because of its high affinity for the PCP site of the NMDA receptor complex, the 3H radiolabelled form of TCP is widely used in research into NMDA receptors.

Oxeladin is a cough suppressant. It is a highly potent and effective drug used to treat all types of cough of various etiologies. It is not related to opium or its derivatives, so treatment with oxeladin is free of risk of dependence or addiction. Oxeladin has none of the side effects (such as hypnosis, respiratory depression, tolerance, constipation and analgesia) which are present when common antitussives, such as codeine and its derivatives, are used. It may be used at every age, as well as in patients with heart disease, since it has a high level of safety and a great selectivity to act on

Ditolylguanidine (DTG) is a sigma receptor agonist. It is somewhat selective for sigma receptors, but non-selective between the two sigma receptor subtypes, binding to both σ1 and σ2 with equal affinity. It has neuroprotective and antidepressant effects, and potentiates the effects of NMDA antagonists.

Ethylketazocine (WIN-35,197-2), is an opioid drug of the benzomorphan family which has been used extensively in scientific research in the last few decades as a tool to aid in the study of the κ-opioid receptor. However, due to its relatively poor selectivity for the κ-opioid receptor over the μ- and δ-opioid receptors (of which it has approximately 80% and 20% of the affinity for, respectively, in comparison), as well as its relatively poor intrinsic activity at all sites (i.e., acts as a partial agonist with mixed agonist and antagonist properties), it has been mostly replaced in recent time

Igmesine (JO-1,784) is a sigma receptor agonist (IC50 = 39&nbsp;nM (rat brain)). It has neuroprotective and antidepressant-like effects in animal studies, as well as nootropic effects in models of age-related cognitive decline. In two phase II clinical trials, igmesine was found to be effective in the treatment of depression and was as active as the comparator fluoxetine. However, in a large phase III clinical trial, igmesine failed to show significant effectiveness for depression. The drug has not been developed further. ==References==

Alazocine (developmental code name -10047), also known more commonly as '''N-allylnormetazocine (NANM'''), is a synthetic opioid analgesic of the benzomorphan family related to metazocine, which was never marketed. In addition to its opioid activity, the drug is a sigma receptor agonist, and has been used widely in scientific research in studies of this receptor. Alazocine is described as a potent analgesic, psychotomimetic or hallucinogen, and opioid antagonist. Moreover, one of its enantiomers was the first compound that was found to selectively label the σ1 receptor, and led to the discover

Dimemorfan (INN; JAN dimemorfan phosphate; also known as dimemorphan and 3,17-dimethylmorphinan; brand names Astomin, Dastosirr, and Tusben) is an antitussive (cough suppressant) of the morphinan family that is widely used in Japan and is also marketed in Spain and Italy. It was developed by Yamanouchi Pharmaceutical (now Astellas Pharma) and introduced in Japan in 1975. It was later introduced in Spain in 1981 and Japan in 1985.

right|thumb|250px|class=skin-invert-image|Metaphit as a methanesulfonate salt

Prasterone, also known as dehydroepiandrosterone (DHEA) and sold under the brand name Intrarosa among others, is a medication as well as over-the-counter dietary supplement which is used to correct DHEA deficiency due to adrenal insufficiency or old age, as a component of menopausal hormone therapy, to treat painful sexual intercourse due to vaginal atrophy, and to prepare the cervix for childbirth, among other uses. It is taken by mouth, by application to the skin, in through the vagina, or by injection into muscle.

Clorgiline (), or clorgyline (), is a monoamine oxidase inhibitor (MAOI) and investigational antidepressant related to pargyline. Specifically, it is an irreversible and selective inhibitor of monoamine oxidase A (MAO-A). Clorgiline was never marketed, but it has found use in scientific research.

Pridopidine (developmental code name PL-101) is an orally administrated small molecule investigational drug. Pridopidine is a selective and potent sigma-1 receptor agonist. It is being developed by Prilenia Therapeutics and is currently in late-stage clinical development for Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS).

Arketamine (developmental code names PCN-101, HR-071603), also known as '(R)-ketamine or (R)-(&minus;)-ketamine', is the (R)-(&minus;) enantiomer of ketamine. Similarly to racemic ketamine and esketamine, the S(+) enantiomer of ketamine, arketamine is biologically active; however, it is less potent as an NMDA receptor antagonist and anesthetic and thus has never been approved or marketed for clinical use as an enantiopure drug. Arketamine is currently in clinical development as a novel antidepressant.