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PsychedeliaDokholyan Laboratory
Plate 448 of 545Verified

Muscimol

Also known asAgarin · Pantherine · Agarine · 5-Aminomethyl-3-hydroxyisoxazole · 5-(Aminomethyl)-3(2H)-isoxazolone · Pantherin · 3-Hydroxy-5-aminomethylisoxazole · 5-(Aminomethyl)-3-isoxazolol

5-(aminomethyl)-1,2-oxazol-3-one

PubChem CID
4266
Measurements
41
InChIKey
ZJQHPWUVQPJPQT-UHFFFAOYSA-N

I · Summary

What is known

Published passages, each quoted whole and attributed to the database that published it. Two blocks are written here rather than quoted, and both say so where they stand: the synthesized summary at the top, which may draw only on the passages beneath it, and the history note, which cites the works it came from. Every claim in either carries a marker to its source.

What it is

  • Crystals. Formerly used as a sedative and an anti-emetic. (EPA, 1998)

    CAMEO ChemicalsU.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.

  • Muscimol is a member of the class of isoxazoles that is 1,2-oxazol-3(2H)-one substituted by an aminomethyl group at position 5. It has been isolated from mushrooms of the genus Amanita. It has a role as a oneirogen, a psychotropic drug, a GABA agonist and a fungal metabolite. It is an alkaloid, a primary amino compound and a member of isoxazoles.

    ChEBI

  • Muscimol has been used in trials studying the treatment of Epilepsy and Parkinson's Disease.

    DrugBank

  • muscimol has been reported in Amanita gemmata, Amanita pseudosychnopyramis, and other organisms with data available.

    LOTUS - the natural products occurrence database

Recognized use

  • Muscimol, thought to be a agonist of gamma-aminobutyric acid (GABA), was administered to eight neuroleptic-free subjects with tardive dyskinesia. At oral dose levels from 5 to 9 mg, involuntary movements were consistently attenuated, usually in the absence of sedation. These results support the view that pharmacologic attempts to stimulate GABA-mediated synaptic transmission may afford symptomatic relief to patients with tardive dyskinesia.

    Therapeutic Uses

    Hazardous Substances Data Bank (HSDB)PMID 35117Tamminga CA et al; Arch Gen Psychiatry 36 (5): 595-8 (1979)

  • /EXPL/ Six patients undergoing stereotactic procedures for essential tremor received microinjections of muscimol (a gamma-aminobutyric acid-A [GABA(A)] agonist) into the ventralis intermedius thalamus in areas where tremor-synchronous cells were identified electrophysiologically with microelectrode recordings and where tremor reduction occurred with electrical microstimulation. Injections of muscimol but not saline consistently reduced tremor in each patient. The effect had a mean latency of 7 minutes and lasted an average of 9 minutes. /It was proposed/ that GABA-mediated thalamic neuronal inhibition may represent a mechanism underlying the effectiveness of surgery for tremor and that GABA…

    Therapeutic Uses

    Hazardous Substances Data Bank (HSDB)PMID 10443891Pahapill PA et al; Ann Neurol 46 (2): 249-52 (1999)

  • /EXPL/ /A Phase 1 clinical trial sponsored by the National Institute of Neurological Disorders and Stroke (NINDS)/ will examine the safety and effectiveness of infusing ... muscimol into the brain to control seizures in patients with intractable epilepsy (frequent seizures that persist despite therapy). Muscimol, which is similar to a naturally occurring brain chemical called GABA, has been shown to reduce seizures in rats... . The objectives of this study are to test the hypotheses that direct infusion of the brain (convection enhanced delivery) with neurotransmitter receptor agonists is 1) safe and 2) can be used to study the basic pathophysiology of the epileptic focus in human subjects..…

    Therapeutic Uses

    Hazardous Substances Data Bank (HSDB)ClinicalTrials.gov;Brain Infusion of Muscimol to Treat Epilepsy. From a search of https://clinicaltrials.gov/search/intervention=muscimol on November 19, 2008

  • Isolated from Amanita muscaria; Used to study GABA receptors; [Merck Index] Used in studies of GABA-A receptors; [ChemIDplus]

    Use Classification

    Haz-Map, Information on Hazardous Chemicals and Occupational DiseasesMerck Index - O'Neil MJ, Heckelman PE, Dobbelaar PH, Roman KJ (eds). The Merck Index, An Encyclopedia of Chemicals, Drugs, and Biologicals, 15th Ed. Cambridge, UK: The Royal Society of Chemistry, 2013.

  • A GABA A-agonist that causes rapid and reversible suppression of neurophysiological activity.

    Use Classification

    Hazardous Substances Data Bank (HSDB)PMID 18377997Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440580

  • Muscimol is produced naturally in the mushrooms Amanita muscaria, Amanita pantherina, and Amanita gemmata, along with muscarine, muscazone, and ibotenic acid. (L1142)

    Use Classification

    Toxin and Toxin Target Database (T3DB)

How it acts

  • Molecular orbital calculations have been carried out on muscimol. The calculated properties of the molecules are related to the ability of muscimol to displace (3)H-labeled GABA (gamma-butyric acid) from the postsynaptic receptors of human cerebellum, & it is suggested that the dominant influence on the gabaergic activity is the pi-electron distribution in heterocyclic ring.

    Hazardous Substances Data Bank (HSDB)PMID 6290798ARMSTRONG DR ET AL; J THEOR BIOL 97 (2): 267 (1982)

  • Previous electrophysiological studies have shown that the GABA(A)-receptor agonist muscimol is able to markedly increase the firing rate of rat nigral dopamine (DA) neurons. This action of the drug is paradoxical since local microiontophoretic application of the drug is associated with a clearcut inhibition of these neurons. ... An attempt was made to analyze the mechanism of this action of the drug /in this study/. Administration of muscimol (0.25-4.0 mg/kg, iv) was associated with a dose-dependent increase in firing rate as well as an increased bursting activity of the nigral DA neurons. Both these effects of muscimol were clearly antagonised by intravenous administration of the NMDA recep…

    Hazardous Substances Data Bank (HSDB)PMID 11043612Erhardt S, Engberg G; Life Sci 67 (15): 1901-11 (2000)

Behavior carries the pharmacological classes and the acute-effect durations, with plasma half-life kept separate from duration of effect.

History, discovery and cultural use

— Not in this archive. PubChem, ChEMBL and the Human Protein Atlas publish pharmacology, regulation and toxicology, and none of them publishes a heading for when Muscimol was first made, by whom, or how it has been used. That is a gap in the databases this site reads and not a gap in the literature — the history of these compounds is written, at length and under peer review, in the works below. This site does not summarize them; it says where they are. Where a published passage above happens to touch origin or traditional use, it appears inside the entry that carries it.

Histories of this field

Scholarship on psychedelics generally, not on Muscimol specifically. Whether any of these treats this compound is a question for the book, not for this page.

  • Mescaline: A Global History of the First Psychedelic

    Traces mescaline and the peyote and San Pedro cacti from pre-Columbian ritual use through nineteenth-century chemistry to twentieth-century psychiatry and the counterculture.

    Jay M. Mescaline: A Global History of the First Psychedelic. Yale University Press, New Haven and London; 2019. ISBN 9780300231076.

  • Expanding Mindscapes: A Global History of Psychedelicsopen access

    Essays on the international and cross-cultural history of psychedelic science, deliberately decentring the standard North American and European account.

    Dyck E, Elcock C, editors. Expanding Mindscapes: A Global History of Psychedelics. The MIT Press, Cambridge MA; 2023. ISBN 9780262546935 (paper), 9780262376891 (open access). doi:10.7551/mitpress/14417.001.0001.

  • Plants of the Gods: Their Sacred, Healing, and Hallucinogenic Powers

    Botany, ethnography and chemistry of the principal hallucinogenic plants, by the founder of modern ethnobotany and the chemist who first synthesized LSD.

    Schultes RE, Hofmann A, Rätsch C. Plants of the Gods: Their Sacred, Healing, and Hallucinogenic Powers. 2nd ed. Healing Arts Press, Rochester VT; 2001. ISBN 9780892819799.

  • Psychonauts: Drugs and the Making of the Modern Mind

    The tradition of scientific self-experimentation with psychoactive drugs, and its part in the emergence of psychology and of modernism.

    Jay M. Psychonauts: Drugs and the Making of the Modern Mind. Yale University Press, New Haven; 2023. ISBN 9780300257946.

  • Ancient Psychoactive Substances

    Archaeological and bioarchaeological evidence for psychoactive plant use across the ancient world.

    Fitzpatrick SM, editor. Ancient Psychoactive Substances. University Press of Florida, Gainesville; 2018. ISBN 9780813056708.

  • History and Current Status of Psychedelics and Entactogens for the Treatment of Psychiatric Disorders

    A chapter tracing psychedelic and entactogen research from earlier ritual use through the mid-century research period to current clinical trials.

    Stroud C, Posey Norris SM, Matney C, editors. History and Current Status of Psychedelics and Entactogens for the Treatment of Psychiatric Disorders. In: Exploring Psychedelics and Entactogens as Treatments for Psychiatric Disorders: Proceedings of a Workshop. National Academies Press, Washington DC; 2022. NBK587225.

    Workshop proceedings record what participants said; they are not a consensus statement of the National Academies.

  • Pharmacokinetic and Pharmacodynamic Aspects of Peyote and Mescaline: Clinical and Forensic Repercussions

    Peer-reviewed review covering the isolation, synthesis, pharmacology and ritual use of peyote and mescaline.

    Dinis-Oliveira RJ, Pereira CL, da Silva DD. Pharmacokinetic and Pharmacodynamic Aspects of Peyote and Mescaline: Clinical and Forensic Repercussions. Current Molecular Pharmacology 12(3):184–194; 2019. doi:10.2174/1874467211666181010154139.

Institutional archives

  • Heffter Research Institute Funds and coordinates clinical research on psilocybin, and keeps records of the studies it has supported since 1993. Sponsors the research it archives.
  • Multidisciplinary Association for Psychedelic Studies (MAPS) Sponsors clinical research, chiefly on MDMA-assisted therapy, and publishes an archive of historical and contemporary documents. A sponsor and an advocacy organization, not a disinterested archive; its clinical programme has a commercial arm.

The rest of this dossier

  • Affinity — 41 measurements in this archive, equilibrium constants kept apart from functional readouts.
  • Toxicology — 10 published passages, plus any assay in this archive bearing on toxicity.
  • Legal — no DEA record is held here — which is not a finding that this compound is uncontrolled.
  • Systems — where this compound’s targets are transcribed, by brain region and tissue.

Passages via PubChem descriptive sections, aggregating DrugBank, LiverTox, FDA, DEA, HSDB, EPA. Each is quoted whole and attributed to the database that published it. The only prose written here about Muscimol is the history note, which says so on its face and carries a reference for every claim in it.

II · Identity

Structure and descriptors

Descriptors are computed here with RDKit from the structure PubChem returns — not from the archive's stored copy, so an edited local structure cannot reach this table.

2D structural depiction of Muscimol
Depiction served by PubChem for CID 4266. Not redrawn here, so the picture and the identity come from the same record.
Formula
C4H6N2O2R
Molecular weight
114.10g/molR
Exact mass
114.0429DaR
cLogP
-0.57R
TPSA
72.0ŲR
H-bond donors
2R
H-bond acceptors
3R
Rotatable bonds
1R
Aromatic rings
1R
Heavy atoms
8R
Fraction sp³
0.250R
Formal charge
0R

Computed with RDKit 2025.09.2 from the SMILES returned by PubChem. Audit run 26/09/2026.

Bemis–Murcko scaffold

O=c1cco[nH]1

Shared with Ibotenic acid. All families

III · Behavior

Behavioral summary

Class, mechanism, and the duration of acute effects — each quoted from the record or trial that publishes it. Duration of effects and plasma half-life are shown separately, because they are different quantities and diverge by a factor of three or four.

Classification

Duration of acute subjective effects

—

No controlled human trial reporting a duration for this compound is cited here. The archive does hold onset and duration ranges for it, inherited from an earlier build, but their source column is empty and so they cannot be shown. A duration is not inferred from a chemical relative.

Plasma elimination half-life

How fast the body clears the drug — not how long the effects last. The two diverge sharply: LSD is cleared with a half-life of about 2.6 h while its subjective effects run 8–12 h.

No half-life is published for this compound in the sources this site reads.

Primary pharmacological drivers

ChEMBL holds no curated mechanism-of-action record for this compound. The measured affinities below are the evidence this archive has for what it binds.

Mechanism, as published

Quoted verbatim from the database named after each passage, never summarized.

  • Molecular orbital calculations have been carried out on muscimol. The calculated properties of the molecules are related to the ability of muscimol to displace (3)H-labeled GABA (gamma-butyric acid) from the postsynaptic receptors of human cerebellum, & it is suggested that the dominant influence on the gabaergic activity is the pi-electr…
    Hazardous Substances Data Bank (HSDB)PMID 6290798ARMSTRONG DR ET AL; J THEOR BIOL 97 (2): 267 (1982)
  • Previous electrophysiological studies have shown that the GABA(A)-receptor agonist muscimol is able to markedly increase the firing rate of rat nigral dopamine (DA) neurons. This action of the drug is paradoxical since local microiontophoretic application of the drug is associated with a clearcut inhibition of these neurons. ... An attemp…
    Hazardous Substances Data Bank (HSDB)PMID 11043612Erhardt S, Engberg G; Life Sci 67 (15): 1901-11 (2000)
  • In many neurons, increased rates of firing are accompanied by expression of the proto-oncoprotein Fos. ... Fos-like immunoreactivity in the mamillary body and the anterior thalamus /was examined/ following unilateral injections of ... muscimol into the ventral tegmental nucleus of Gudden (VTN). These injections resulted in a marked incre…
    Hazardous Substances Data Bank (HSDB)PMID 8814891Shim I, Wirtshafter D; Brain Res. 1996 Mar 18;712(2):173-8.

IV · Clinical

Clinical description

Where this compound's substance class sits in ICD-11 and DSM-5-TR, and how much of the recorded literature speaks to each domain of a mental status examination.

No diagnostic chapter is shown for this compound. Either PubChem records no MeSH pharmacological class for it, or the class it records is not one of the substance classes ICD-11 gives a chapter to. Inferring a chapter from the compound’s name or its binding profile would be a diagnosis this archive is in no position to make.

How much has been written about each domain

The clinical domains, and how many of the records this archive holds for this compound say something under each. What the terms mean, and the word list behind every spoke, are set out in the method.

Affect0Mood1Perception1Cognition0Thought process0Thought content0Psychomotor activity1Insight and judgment0
This measures the literature, not the compound. Each spoke counts how many of the 13 records this archive holds for this compound say something under that domain — 1 at the widest ring. A long spoke means the subject has been written about, not that the effect is strong, and a spoke at the center means nothing here discusses it rather than that nothing happens. The terms behind each domain are listed in the method.
Mood 1
matched on “elation”, “euphoria”, “irritab” · in Toxicology: Hazardous Substances Data Bank (HSDB)
Perception 1
matched on “hallucinat”, “hallucinogen” · in Toxicology: Hazardous Substances Data Bank (HSDB)
Psychomotor activity 1
matched on “restless”, “stupor” · in Toxicology: Hazardous Substances Data Bank (HSDB)

V · Systems

Systems physiology

Where the targets this compound binds are transcribed — brain regions on the left, peripheral and autonomic tissues on the right. A join of two measurements, not a claim about what the compound does to either.

Brain

cerebral cortex — 1.8 nTPM, from ADRB2cerebellum — 0.5 nTPM, from ADRB2hippocampal formation — 2.1 nTPM, from ADRB2amygdala — 2.1 nTPM, from ADRB2hypothalamus — 1.2 nTPM, from ADRB2thalamus — no resolved target expressed herebasal ganglia — 1.6 nTPM, from ADRB2medulla oblongata — no resolved target expressed here

basal ganglia: drawn as the caudate nucleus, putamen and globus pallidus.

Measured but not drawn — this anatomogram has no outline for them: retina 22.8, midbrain 2.4, spinal cord 2.2, pituitary gland 0.5.

Body

heart — 6.3 nTPM, from ADRB2smooth muscle — 3.5 nTPM, from ADRB2lung — 18.4 nTPM, from ADRB2liver — 13.3 nTPM, from ADRB2kidney — 1.8 nTPM, from ADRB2, GABRR1stomach — 7.1 nTPM, from ADRB2duodenum — 1.8 nTPM, from ADRB2small intestine — 3.5 nTPM, from ADRB2colon — 2.9 nTPM, from ADRB2adrenal gland — 1.6 nTPM, from ADRB2thyroid gland — 1.8 nTPM, from ADRB2pancreas — 1.1 nTPM, from ADRB2urinary bladder — 6.4 nTPM, from ADRB2, GABRR1skeletal muscle — 10.9 nTPM, from ADRB2, GABRR1spleen — 7.9 nTPM, from ADRB2salivary gland — 6.9 nTPM, from ADRB2
023 nTPM

Square-root ramp · shared scale across both plates

Shading is transcript level — not affinity, and not affinity combined with expression. Outlined but unshaded organs hold none of this compound’s resolved targets above the atlas’s detection threshold. Anatomy from EMBL-EBI Anatomogram (Apache License 2.0); regions identified by Uberon (uberon.org), CC BY 3.0.

Brain regions

Regions where this compound's measured targets are transcribed. Linked from the plate above.

  1. retina

    22.8 nTPM
    • Gamma-aminobutyric acid receptor subunit rho-1GABRR16.2 pX22.8
    • Beta2ADRB26.7 pX0.5

  2. midbrain

    2.4 nTPM

  3. spinal cord

    2.2 nTPM

  4. hippocampal formation

    2.1 nTPM

  5. amygdala

    2.1 nTPM

  6. cerebral cortex

    1.8 nTPM

  7. basal ganglia

    1.6 nTPM

  8. hypothalamus

    1.2 nTPM

  9. cerebellum

    0.5 nTPM

  10. pituitary gland

    0.5 nTPM

Peripheral & autonomic

Tissues outside the CNS expressing the same targets — where a compound's bodily effects become possible.

  1. lung

    18.4 nTPM

  2. liver

    13.3 nTPM

  3. skeletal muscle

    10.9 nTPM
    • Beta2ADRB26.7 pX10.9
    • Gamma-aminobutyric acid receptor subunit rho-1GABRR16.2 pX0.1

  4. spleen

    7.9 nTPM

  5. stomach 1

    7.1 nTPM

  6. salivary gland

    6.9 nTPM

  7. urinary bladder

    6.4 nTPM
    • Beta2ADRB26.7 pX6.4
    • Gamma-aminobutyric acid receptor subunit rho-1GABRR16.2 pX0.1

  8. heart muscle

    6.3 nTPM

  9. smooth muscle

    3.5 nTPM

  10. small intestine

    3.5 nTPM

  11. colon

    2.9 nTPM

  12. kidney

    1.8 nTPM
    • Beta2ADRB26.7 pX1.8
    • Gamma-aminobutyric acid receptor subunit rho-1GABRR16.2 pX0.1

  13. duodenum

    1.8 nTPM

  14. thyroid gland

    1.8 nTPM

  15. adrenal gland

    1.6 nTPM

  16. pancreas

    1.1 nTPM

Each row joins two published measurements and nothing else: the affinity this archive holds for the compound at that target, and the transcript level the Human Protein Atlas reports for that target’s gene in that region. Bars scale with expression only. Expression is not activation — a receptor transcribed in a region is a receptor available to be bound there, which is a weaker and more defensible claim than saying the region is affected.

6 of this compound’s targets could not be resolved to a gene and are absent from both columns: Alpha-1, Alpha-2, GABA-A receptor; agonist GABA site, GABAA, GABAB, Gamma-aminobutyric acid receptor subunit gamma-1.

Expression data from Human Protein Atlas (CC BY-SA 3.0), RNA expression, nTPM (normalized transcripts per million), consensus tissue dataset. Uhlén M, et al. Tissue-based map of the human proteome. Science. 2015;347(6220):1260419.

VI · Profile

Affinity rosette

The strongest measurement at each of 8 molecular targets. Cell-line and whole-organism screens are excluded here — they carry no affinity — and appear in the table below.

Beta2 — EC50 6.68 pXAlpha-2 — EC50 6.39 pXAlpha-1 — EC50 6.27 pXGABAA — Ki 8.89 pXGamma-aminobutyric acid receptor subunit gamma-1 — IC50 8.22 pXGABAB — Ki 6.34 pXGamma-aminobutyric acid receptor subunit rho-1 — EC50 6.16 pXGABA-A receptor; agonist GABA site — EC50 4.57 pXBeta2Alpha-2Alpha-1GABAAGamma-aminobutyr…GABABGamma-aminobutyr…GABA-A receptor;…579
Fig. Radius is pX = −log₁₀(value in M), that is 9 − log₁₀(value in nM), computed from the normalized measurement. Hatched wedges are equilibrium binding constants (Ki, Kd); dashed outlines are functional readouts (IC₅₀, EC₅₀, AC₅₀, potency), which answer a different question and are not pooled with them. Rings mark whole pX units from 5 to 10, labeled every second ring in the gutter at the top. Where a target carries several measurements, the strongest is drawn.

VII · Toxicology

Toxicological profile

What has been measured, and what has been published — kept apart, and neither scored. There is no risk rating on this page; the archive once carried one, identical for every compound, produced by a stub.

Measured in this archive

Assays that bear on toxicity, drawn from the same ChEMBL records as everything else on this page. They are measurements of what a compound binds or does to cells — not verdicts about what it does to a person.

No hERG, cytochrome, cytotoxicity or transport measurement exists for Muscimol in this archive.

Lethal-dose values — animal studies

These are not human doses. An LD50 is the dose killing half of a group of animals of one species by one route, and it is a poor predictor of human risk for these compounds. Each value is printed whole, with the species and route it was measured in, because a lethal dose separated from those two facts is worse than no figure at all. Nothing here supports inferring a safe dose for anyone.

  • LD50 Mouse sc 3.8 mg/kg

    Hazardous Substances Data Bank (HSDB)Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989., p. 995

  • LD50 Mouse ip 2.5 mg/kg

    Hazardous Substances Data Bank (HSDB)Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989., p. 995

  • LD50 Rat iv 4.5 mg/kg

    Hazardous Substances Data Bank (HSDB)Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989., p. 995

  • LD50 Rat oral 45 mg/kg

    Hazardous Substances Data Bank (HSDB)Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989., p. 995

As published

Quoted verbatim from the database named after each passage, never summarized — a summary of a toxicology statement is a new claim.

Toxicity Summary

  • Muscimol is a potent GABAA agonist, activating the receptor for the brain's major inhibitory neurotransmitter, GABA. Muscimol actually binds to the same binding site on the GABAA receptor complex as GABA itself, as opposed to other GABAergic drugs such as barbiturates and benzodiazepines which bind to separate regulatory sites. GABAA receptors are widely distributed in the brain, and so when muscimol is administered,…

    Toxin and Toxin Target Database (T3DB)

Human Toxicity Excerpts

  • /HUMAN EXPOSURE STUDIES/ Human volunteers who ingested 7.5 mg muscimol or 50 to 90 mg ibotenic acid experienced within an hour symptoms that lasted 3 to 4 hours, with a few effects that lingered for about 10 hours and a hangover (headache) the next day. Subjects became inactive and experienced fatigue (the mushrooms also often cause an initial drowsiness, stupor or sleep), mild nausea and vomiting, muscle spasms in t…

    Hazardous Substances Data Bank (HSDB)Gosselin, R.E., R.P. Smith, H.C. Hodge. Clinical Toxicology of Commercial Products. 5th ed. Baltimore: Williams and Wilkins, 1984., p. II-248

  • /SIGNS AND SYMPTOMS/ Intoxication produced by Amanita muscaria & related species arises from anticholinergic & hallucinogenic properties of variety of isoxazole deriv. symptoms incl irritability, restlessness, ataxia, hallucinations, & delirium. /Isoxazole deriv of Amanita muscaria & related species/

    Hazardous Substances Data Bank (HSDB)Gilman, A. G., L. S. Goodman, and A. Gilman. (eds.). Goodman and Gilman's The Pharmacological Basis of Therapeutics. 6th ed. New York: Macmillan Publishing Co., Inc. 1980., p. 98

  • /SIGNS AND SYMPTOMS/ Amanita muscaria ... causes salivation, perspiration, nausea, bradycardia, and mydriasis. ... One to four mushrooms cause euphoria, a sense of lightness, colored visions, and visual hallucinations. Although muscarine is a constituent of these mushrooms, there is no constriction of the pupils in this poisoning. Instead there is mydriasis, which is thought to be a sympathetic effect from action on…

    Hazardous Substances Data Bank (HSDB)Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986., p. 74

  • /SIGNS AND SYMPTOMS/ The /emotional change/ is sufficiently attractive to some that Amanita pantherina (which is more potent and more toxic than Amanita muscaria) is collected in the Pacific northwest and consumed (raw or cooked) for recreational purposes. Specimens of the fly agaric found in the eastern USA (especially the yellow variety) are said to be much less psychoactive than those collected in the west. Only r…

    Hazardous Substances Data Bank (HSDB)Gosselin, R.E., R.P. Smith, H.C. Hodge. Clinical Toxicology of Commercial Products. 5th ed. Baltimore: Williams and Wilkins, 1984., p. II-248

  • For more Human Toxicity Excerpts (Complete) data for MUSCIMOL (9 total), please visit the HSDB record page.

    Hazardous Substances Data Bank (HSDB)

Published passages via PubChem toxicology sections, aggregating Hazardous Substances Data Bank (HSDB), RTECS, LiverTox. No figure on this page is scored, ranked or combined into a risk level.

VIII · Evidence

Every measurement

One row per published value. The identifier in the last column resolves to the ChEMBL assay record it was read from.

Equilibrium binding constants 21

Ki and Kd — a concentration at equilibrium. Directly comparable across rows at the same target.

TargetClassTypeValue (nM)pXOrganismAssay
GABAAGABA receptorsKi1.308.89HUMANPMID 9396785
UncheckedUnclassifiedKi2.608.59— organism not recordedCHEMBL1020117
GABAAGABA receptorsKi2.888.54HUMANPMID 9396785
GABAAGABA receptorsKi4.008.40Rattus norvegicusCHEMBL680229
GABAAGABA receptorsKi4.308.37HUMANPMID 9396785
GABAAGABA receptorsKi4.578.34HUMANPMID 9396785
GABAAGABA receptorsKi5.008.30HUMANPMID 9396785
GABAAGABA receptorsKi5.378.27HUMANPMID 9396785
GABAAGABA receptorsKi5.758.24HUMANPMID 9396785
GABAAGABA receptorsKi6.008.22Homo sapiensCHEMBL3370250
GABAAGABA receptorsKi6.108.21HUMANPMID 9396785
GABAAGABA receptorsKi6.768.17HUMANPMID 9396785
GABAAGABA receptorsKi6.808.17HUMANPMID 9396785
UncheckedUnclassifiedKi7.008.15— organism not recordedCHEMBL2317990
GABAAGABA receptorsKi8.318.08HUMANPMID 9396785
GABAAGABA receptorsKi8.408.08HUMANPMID 9396785
GABAAGABA receptorsKi8.918.05HUMANPMID 9396785
GABAAGABA receptorsKi9.108.04HUMANPMID 9396785
GABAAGABA receptorsKi11.007.96Homo sapiensCHEMBL681334
UncheckedUnclassifiedKd15.207.82— organism not recordedCHEMBL2417020
GABABGABA receptorsKi4606.34HUMANPMID 11093776

Functional readouts 20

IC₅₀, EC₅₀, AC₅₀ and potency. Assay-dependent, and not interchangeable with a binding constant.

TargetClassTypeValue (nM)pXOrganismAssay
GABAAGABA receptorsIC503.008.52Rattus norvegicusCHEMBL681302
GABAAGABA receptorsIC503.208.49Rattus norvegicusCHEMBL681130
GABAAGABA receptorsIC505.008.30Rattus norvegicusCHEMBL681138
GABAAGABA receptorsIC506.008.22Rattus norvegicusCHEMBL681137
GABAAGABA receptorsIC506.008.22Rattus norvegicusCHEMBL681241
Gamma-aminobutyric acid receptor subunit gamma-1GABA receptorsIC506.008.22Rattus norvegicusCHEMBL681136
GABAAGABA receptorsIC5010.008.00Rattus norvegicusCHEMBL681240
GABAAGABA receptorsIC5016.007.80Homo sapiensCHEMBL881988
UncheckedUnclassifiedEC5053.707.27— organism not recordedCHEMBL3370496
UncheckedUnclassifiedEC5054.007.27— organism not recordedCHEMBL3370496
Beta2Adrenergic receptorsEC502106.68Homo sapiensCHEMBL3370259
Beta2Adrenergic receptorsEC502146.67Homo sapiensCHEMBL3370259
Alpha-2Adrenergic receptorsEC504076.39Homo sapiensCHEMBL3370257
Alpha-2Adrenergic receptorsEC504106.39Homo sapiensCHEMBL3370257
Alpha-1Adrenergic receptorsEC505376.27Homo sapiensCHEMBL3370251
Alpha-1Adrenergic receptorsEC505406.27Homo sapiensCHEMBL3370251
Gamma-aminobutyric acid receptor subunit rho-1GABA receptorsEC506926.16Homo sapiensCHEMBL3370253
Gamma-aminobutyric acid receptor subunit rho-1GABA receptorsEC507006.15Homo sapiensCHEMBL3370253
Gamma-aminobutyric acid receptor subunit rho-1GABA receptorsEC502,3005.64Homo sapiensCHEMBL2340049
GABA-A receptor; agonist GABA siteGABA receptorsEC5027,0004.57Homo sapiensCHEMBL2340052
P
PubChem
C
ChEMBL
R
Computed here with RDKit
D
Derived here from the stored measurement

IX · Trials

Registered clinical trials

Studies filed with ClinicalTrials.gov that name this compound as an intervention. A registered trial is a protocol, not a result — status and enrollment are printed beside every row, and withdrawn studies are counted rather than hidden.

2T

Registered studies

0T

Open or ongoing

2T

With a phase recorded

By phase

A study may carry two phase codes at once, so these count studies bearing each phase and do not sum to the total.

  • Phase 12

By status

The registry’s own status for each record. Withdrawn and terminated studies are counted here rather than hidden — a stopped trial is part of what is known.

  • Withdrawn1
  • Terminated1

Every matched study

Newest first by start date. Each identifier opens the registry record it came from; the title is the sponsor’s own, quoted.

  • NCT00921128Withdrawn · Phase 1

    Convection-Enhanced Delivery to Study the Pathophysiology Underlying the Clinical Features of Parkinson s Disease

    Enrollment
    0Tactual
    Started
    2009-06-02
    Sponsor
    National Institute of Neurological Disorders and Stroke (NINDS)

    Conditions Parkinson's Disease

    Matched “Muscimol” in the study’s intervention “Muscimol”

  • NCT00005925Terminated · Phase 1

    Brain Infusion of Muscimol to Treat Epilepsy

    Enrollment
    3Tactual
    Started
    2000-06-23
    Sponsor
    National Institute of Neurological Disorders and Stroke (NINDS)

    Conditions Epilepsy

    Matched “Muscimol” in the study’s intervention “Muscimol”

Records from ClinicalTrials.gov (U.S. National Library of Medicine, NIH), API v2. A study is listed against a compound only when a verified name for that compound appears as a whole word in one of the study's own intervention names. A short code must appear as written, and a name the registry uses for something else (Aleph, a vaccine maker) is not matched. Title matches are not accepted. The matched name and the intervention text it matched are shown with every row.

Searched as Muscimol · Pantherine · 5-Aminomethyl-3-hydroxyisoxazole. Run this search at the registry — it returns the unfiltered result, including studies this page rejected as belonging to a different molecule.

A registered trial is a protocol somebody filed with the registry. It is not a result, and nothing on this plate says whether Muscimol worked.

XI · Literature

Sources behind this dossier

The papers this compound's values were read from, ranked by what each contributed. Not a review of the field.

Every paper below is one some value on this page came from — a binding constant, a passage of pharmacology or toxicology, or a measured duration. Each entry says what this archive took from it. Nothing else is claimed about any of them: the title is the study’s own account of itself, and a summary written here would be an assertion with no source behind it.

  1. 01

    Differences in agonist/antagonist binding affinity and receptor transduction using recombinant human gamma-aminobutyric acid type A receptors

    Ebert B, Thompson SA, Saounatsou K et al. · Molecular pharmacology 1997

    • · 14 measurements at 1 target (Ki), strongest GABAA at 8.89 pX

    PMID 9396785

  2. 02

    Correlation of the apparent affinities and efficacies of gamma-aminobutyric acid(C) receptor agonists

    Chang Y, Covey DF, Weiss DS · Molecular pharmacology 2000

    • · 1 measurement at 1 target (Ki), strongest GABAB at 6.34 pX

    PMID 11093776

  3. 03

    Excitation of nigral dopamine neurons by the GABA(A) receptor agonist muscimol is mediated via release of glutamate

    Erhardt S, Engberg G · Life sciences 2000

    • · Mechanism of Action

    PMID 11043612

  4. 04

    Fos-like immunoreactivity in the mamillary body and thalamus following injections of muscimol into the ventral tegmental nucleus of Gudden in the rat

    Shim I, Wirtshafter D · Brain research 1996

    • · Mechanism of Action

    PMID 8814891

  5. 05

    Muscimol and some aza analogues: molecular orbital calculations relating to their potency as GABA mimetics

    Armstrong DR, Breckenridge RJ, Suckling CJ · Journal of theoretical biology 1982

    • · Mechanism of Action

    PMID 6290798