Muscimol: A neurotoxic isoxazole isolated from species of AMANITA. It is obtained by decarboxylation of IBOTENIC ACID. Muscimol is a potent agonist of GABA-A RECEPTORS and is used mainly as an experimental tool in animal and tissue studies.GABA Agonists: Endogenous compounds and drugs that bind to and activate GAMMA-AMINOBUTYRIC ACID receptors (RECEPTORS, GABA).GABA-A Receptor Agonists: Endogenous compounds and drugs that bind to and activate GABA-A RECEPTORS.Receptors, GABA-A: Cell surface proteins which bind GAMMA-AMINOBUTYRIC ACID and contain an integral membrane chloride channel. Each receptor is assembled as a pentamer from a pool of at least 19 different possible subunits. The receptors belong to a superfamily that share a common CYSTEINE loop.Bicuculline: An isoquinoline alkaloid obtained from Dicentra cucullaria and other plants. It is a competitive antagonist for GABA-A receptors.gamma-Aminobutyric Acid: The most common inhibitory neurotransmitter in the central nervous system.Allylamine: Possesses an unusual and selective cytotoxicity for VASCULAR SMOOTH MUSCLE cells in dogs and rats. Useful for experiments dealing with arterial injury, myocardial fibrosis or cardiac decompensation.Back Muscles: Musculature of the BACK.Microinjections: The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.Palmitoylcarnitine: A long-chain fatty acid ester of carnitine which facilitates the transfer of long-chain fatty acids from cytoplasm into mitochondria during the oxidation of fatty acids.Cerebellar Nuclei: Four clusters of neurons located deep within the WHITE MATTER of the CEREBELLUM, which are the nucleus dentatus, nucleus emboliformis, nucleus globosus, and nucleus fastigii.Flunitrazepam: A benzodiazepine with pharmacologic actions similar to those of DIAZEPAM that can cause ANTEROGRADE AMNESIA. Some reports indicate that it is used as a date rape drug and suggest that it may precipitate violent behavior. The United States Government has banned the importation of this drug.GlucosephosphatesGABA-A Receptor Antagonists: Drugs that bind to but do not activate GABA-A RECEPTORS thereby blocking the actions of endogenous or exogenous GABA-A RECEPTOR AGONISTS.Receptors, GABA-B: A subset of GABA RECEPTORS that signal through their interaction with HETEROTRIMERIC G-PROTEINS.Nipecotic AcidsGlossitis, Benign Migratory: An idiopathic disorder characterized by the loss of filiform papillae leaving reddened areas of circinate macules bound by a white band. The lesions heal, then others erupt.Medulla Oblongata: The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.GABA Agents: Substances used for their pharmacological actions on GABAergic systems. GABAergic agents include agonists, antagonists, degradation or uptake inhibitors, depleters, precursors, and modulators of receptor function.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Pons: The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM.GABA-B Receptor Agonists: Endogenous compounds and drugs that bind to and activate GABA-B RECEPTORS.Rats, Long-Evans: An outbred strain of rats developed in 1915 by crossing several Wistar Institute white females with a wild gray male. Inbred strains have been derived from this original outbred strain, including Long-Evans cinnamon rats (RATS, INBRED LEC) and Otsuka-Long-Evans-Tokushima Fatty rats (RATS, INBRED OLETF), which are models for Wilson's disease and non-insulin dependent diabetes mellitus, respectively.Secobarbital: A barbiturate that is used as a sedative. Secobarbital is reported to have no anti-anxiety activity.Pentobarbital: A short-acting barbiturate that is effective as a sedative and hypnotic (but not as an anti-anxiety) agent and is usually given orally. It is prescribed more frequently for sleep induction than for sedation but, like similar agents, may lose its effectiveness by the second week of continued administration. (From AMA Drug Evaluations Annual, 1994, p236)Hemorrhage: Bleeding or escape of blood from a vessel.Diazepam: A benzodiazepine with anticonvulsant, anxiolytic, sedative, muscle relaxant, and amnesic properties and a long duration of action. Its actions are mediated by enhancement of GAMMA-AMINOBUTYRIC ACID activity.Chlormethiazole: A sedative and anticonvulsant often used in the treatment of alcohol withdrawal. Chlormethiazole has also been proposed as a neuroprotective agent. The mechanism of its therapeutic activity is not entirely clear, but it does potentiate GAMMA-AMINOBUTYRIC ACID receptors response and it may also affect glycine receptors.

*  Temporary inactivation of the dorsal entorhinal cortex impairs acquisition and retrieval of spatial information.

Muscimol / pharmacology. Neuropsychological Tests. Rats. Rats, Long-Evans. Receptors, GABA-A / agonists, metabolism. Space ... 0/GABA Agonists; 0/Receptors, GABA-A; 2763-96-4/Muscimol From MEDLINE®/PubMed®, a database of the U.S. National Library of ... In contrast, rats that received bilateral, intra-entorhinal infusions of muscimol, a gamma-aminobutyric acid(a) (GABA(a)) ...
biomedsearch.com/nih/Temporary-inactivation-dorsal-entorhinal-cortex/19800978.html

*  The anterior thalamus is critical for overcoming interference in a context-dependent odor discrimination task.

Muscimol / pharmacology. Odors. Olfactory Perception / drug effects, physiology*. Rats. Rats, Long-Evans. Smell / drug effects ...
biomedsearch.com/nih/anterior-thalamus-critical-overcoming-interference/23025833.html

*  Plus it

First, cortical infusion of the GABA receptor (GABAA) agonist muscimol results in a paradoxical shift of OD toward the deprived ... The generalized reduction in NTFs that probably results from muscimol infusion might therefore shift the balance between these ... Elliott and Shadbolt, 1996). It is also possible that muscimol infusion interferes with inhibitory circuitry. ... eye (Reiter and Stryker, 1988; Hata and Stryker, 1994). Muscimol infusion is likely to cause a generalized decrease in the ...
jneurosci.org/content/18/15/5850

*  ARTICLES | Journal of Neurophysiology

I. Effect of muscimol and bicuculline in monkey superior colliculus. J Neurophysiol 53:266-291. ...
jn.physiology.org/content/84/5/2605.full

*  Datura safety - The Ethnobotanical Garden - Shroomery Message Board

Muscimol, one of two prominent chemicals in Fly Agarics, is a CNS Depressant. Ibotenic acid, the other chem, is a Cholinergic ... Monkshood and muscimol counter the effects of anticholinergenics. Monkshood is highly toxic and this isn't recomend as its like ...
https://shroomery.org/forums/showflat.php/Number/1800792

*  The Pharmacology of Mesocortical Dopamine Neurons: A Dual-Probe Microdialysis Study in the Ventral Tegmental Area and...

2), muscimol (20 μmol/l) infusions into the VTA decreased extracellular dopamine in the PFC to about 60% of controls. In ... The finding that muscimol interacts in opposite ways with the two dopamine systems is of theoretical interest, because it opens ... The GABAA agonist muscimol was infused via the microdialysis probe into the VTA in concentrations of 20 μmol/l. The infusions ... Infusion of the GABAA agonist muscimol and the GABAB agonist baclofen into the VTA clearly decreased extracellular dopamine in ...
jpet.aspetjournals.org/content/285/1/143.full

*  strabismus | Journal of Neurophysiology

Muscimol inactivation of caudal fastigial nucleus and posterior interposed nucleus in monkeys with strabismus Anand C. Joshi, ...
jn.physiology.org/keyword/strabismus-0

*  1999 Curt P. Richter award. Glucocorticoids and the regulation of memory consolidation.

19447274 - Muscimol state-dependent memory: involvement of dorsal hippocampal mu-opioid receptors.. 1937064 - Disturbance of ...
biomedsearch.com/nih/1999-Curt-P-Richter-award/10737694.html

*  K+ Channel TASK-1 Knockout Mice Show Enhanced Sensitivities to Ataxic and Hypnotic Effects of GABAA Receptor Ligands | Journal...

Sections were preincubated for 15 min for [3H]Ro 15-4513 and [3H]muscimol binding in ice-cold 50 mM Tris-HCl, pH 7.4, +120 mM ... GABAA Receptor Ligand Autoradiography. We used the ligands [3H]Ro 15-4513, [3H]muscimol, and t-butyl-bicyclophosphoro-[35S] ... muscimol indicated no change in α4βδ receptor levels in the brain samples between TASK-1 KO and control mice nor between males ... Muscimol binding to TASK-1 KO and control littermate brain sections was similar (Table 1), suggesting that there was no change ...
jpet.aspetjournals.org/content/327/1/277.full

*  Plus it

1996b) The phase shifting effects of NPY, but not Muscimol, require sodium dependent synaptic transmission in the SCN. Soc Res ...
jneurosci.org/content/17/21/8468

*  10 Intoxicating Ways Animals Use Drugs - Listverse

This has not stopped people eating them because they also contain a psychoactive drug called muscimol. ...
listverse.com/2017/03/23/10-intoxicating-ways-animals-use-drugs/?utm_source=more&utm_medium=link&utm_campaign=direct

*  Gene Therapy for Parkinson's Disease

R. Levy, A. E. Lang, J. O. Dostrovsky et al., "Lidocaine and muscimol microinjections in subthalamic nucleus reverse ...
https://hindawi.com/journals/pd/2012/757305/

*  Table of Contents - February 01, 1997, 28 (2) | Stroke

Medical Therapy for Intracerebral Hematoma With the γ-Aminobutyric Acid-A Agonist Muscimol Patrick D. Lyden, Catherine Jackson- ...
stroke.ahajournals.org/content/28/2

*  W Loscher

Lack of robust anticonvulsant effects of muscimol microinfusions in the anterior substantia nigra of kindled rats. M Gernert. ... in kindled rats the anterior pars reticulata of the substantia nigra is not a site at which muscimol causes robust ...
https://labome.org/expert/germany/university/loscher/w-loscher-676793.html

*  Ácido gama-aminobutírico - Wikipedia

Inalantes Muscimol (encontrado nos cogumelos Amanita Muscaria) Esteróides neuroativos Não-benzodiazepínicos Eszopiclona ( ... Ligantes do receptor GABAC Agonistas Muscimol (encontrado no cogumelo Amanita Muscaria) Antagonistas TPMPA Inibidores da ...
https://pt.wikipedia.org/wiki/Ácido_gama-aminobutírico

*  Inocybe, clitocybe, omphalotus and others (Group PIM G028)

... muscimol, muscazone or ibotenic acid. 4. USES/CIRCUMSTANCES OF POISONING 4.1 Uses 4.1.1 Uses 4.1.2 Description In most cases, ...
inchem.org/documents/pims/fungi/pimg028.htm

*  Role of the prefrontal cortex and nucleus accumbens in reinstating methamphetamine seeking.

... rats were bilaterally microinjected with either a combination of the GABA agonists baclofen/muscimol or vehicle (artificial ...
https://omicsonline.org/references/role-of-the-prefrontal-cortex-and-nucleus-accumbens-in-reinstating-methamphetamine-seeking-519341.html

*  JoVE | Peer Reviewed Scientific Video Journal - Methods and Protocols

Anesthetic (1ul Muscimol 20mM) and Microspheres (Chris Fang-Yen personal communication) (1ul 2.65% Polystyrene 0.1 um in water ...
https://jove.com/visualize/abstract/23144786/spherical-lenses-prisms-lead-to-postural-instability-both-dyslexic

*  gamma-Hydroxybutyric acid - Wikipedia

GHB has at least two distinct binding sites[85] in the central nervous system. GHB is an agonist at the newly characterized GHB receptor, which is excitatory,[86][87] and it is a weak agonist at the GABAB receptor, which is inhibitory.[87] GHB is a naturally occurring substance that acts in a similar fashion to some neurotransmitters in the mammalian brain.[88] GHB is probably synthesized from GABA in GABAergic neurons, and released when the neurons fire.[87]. GHB has been found to activate oxytocinergic neurons in the supraoptic nucleus.[89]. If taken orally, GABA itself does not effectively cross the blood-brain-barrier.[90]. GHB induces the accumulation of either a derivative of tryptophan or tryptophan itself in the extracellular space, possibly by increasing tryptophan transport across the blood-brain barrier. The blood content of certain neutral amino-acids, including tryptophan, is also increased by peripheral GHB administration. GHB-induced stimulation of tissue serotonin turnover may be ...
https://en.wikipedia.org/wiki/Gamma-hydroxybutyric_acid

*  Thujone - Wikipedia

Based on studies that looked only at molecular shape, for many years thujone was thought to act similarly to THC on the cannabinoid receptors;[8] however, this has since been proven false.[9] Thujone is a GABAA receptor antagonist.[10] By inhibiting GABA receptor activation, neurons may fire more easily, which can cause muscle spasms and convulsions.[11] Thujone is also a 5-HT3 antagonist.[12][13]. The median lethal dose, or LD50, of alpha-thujone, the more active of the two isomers, in mice, is around 45 mg/kg, with 0% mortality rate at 30 mg/kg and 100% at 60 mg/kg. Mice exposed to the higher dose have convulsions that lead to death within 1 minute. From 30 to 45 mg/kg, the mice experience muscle spasms in the legs, which progress to general convulsions until death or recovery. Pretreatment with diazepam, phenobarbital, or 1 g/kg of ethanol protects against a lethal dose of 100 mg/kg. These effects are in line with other GABA antagonists. Also, alpha-thujone is metabolized quickly in the liver ...
https://en.wikipedia.org/wiki/Thujone

*  trihexyphenidyl - meddic

Trihexyphenidyl is used for the symptomatic treatment of Parkinson's disease in mono and combination therapy. It is active in postencephalitic, arteriosclerotic, and idiopathic forms. The drug is also commonly used to treat extrapyramidal side effects occurring during antipsychotic treatment. It reduces the frequency and duration of oculogyric crises as well as of dyskinetic movements and spastic contractions. Trihexyphenidyl may improve psychotic depression and mental inertia frequently associated with Parkinson's disease and symptomatic problems caused by antipsychotic treatment.[medical citation needed]. The drug cannot cure Parkinson's disease, but may provide substantial alleviation of symptoms.An estimated 50 to 75% of people with Parkinson's disease will react positively and experience a 20 to 30% symptomatic improvement. To increase therapeutic activity trihexyphenidyl is often given concomitantly with levodopa, other antimuscarinic or antihistaminic (e.g. diphenhydramine) agents. ...
meddic.jp/trihexyphenidyl

*  legal psychedelics for sale | Simon's Legal Highs

The main active ingredient in fly agaric is muscimol. The mushroom has a sacred significance in Siberia; where it was ...
https://simonsblogpark.com/legalhigh/tag/legal-psychedelics-for-sale/

*  GABRA6 - Anti-GABRA6 Antibodies, shRNA, siRNA & Gene Information | Sigma-Aldrich

Muscimol hydrobromide ≥98% (HPLC), solid human pricing P9159 Piperidine-. 4-. sulfonic acid human pricing ...
sigmaaldrich.com/catalog/genes/GABRA6?lang=en®ion=

*  How sounds may cheat sight? Introduction to a article from Neuron Neuron 73, 814-828, February 23, ppt download

14 Acute activation of L5Ps by local perfusion of Muscimol counteracted the SHs in L2/3 Result 4: Sound-Driven Activation of an ...
slideplayer.com/slide/3829474/

*  Psychedelic drug - The Full Wiki

Eszopiclone • Gaboxadol • Ibotenic Acid • Muscimol • Zaleplon • Zolpidem • Zopiclone. Others. Efavirenz • Glaucine • Isoaminile ...
thefullwiki.org/Psychedelic_drug

*  Psilocybin : Wikis (The Full Wiki)

Eszopiclone • Gaboxadol • Ibotenic Acid • Muscimol • Zaleplon • Zolpidem • Zopiclone. Others. Efavirenz • Glaucine • Isoaminile ...
thefullwiki.org/Psilocybin

Org 20599BicucullinePivagabineAminoallyl nucleotide: Aminoallyl nucleotide is a nucleotide with a modified base containing an allylamine. They are used in post-labeling of nucleic acids by fluorescence detection in microarray.Hydrostatic shock: 400px|right|thumb|Average time until incapacitation decreases rapidly with pressure wave magnitude as magnitudes approach . See: Links between traumatic brain injury and ballistic pressure waves originating in the thoracic cavity and extremities.Interposed nucleus: The interposed nucleus is a deep nucleus of the cerebellum and is composed of the globose nuclei and the emboliform nuclei. It is located in the roof (dorsal aspect) of the fourth ventricle, lateral to the fastigial nucleus.FlunitrazepamNipecotic acid: Nipecotic acid is a GABA reuptake inhibitor used in scientific research.Rostral ventromedial medulla: The rostral ventromedial medulla (RVM), or ventromedial nucleus of the spinal cord, is a group of neurons located close to the midline on the floor of the medulla oblongata (myelencephalon). The rostral ventromedial medulla sends descending inhibitory and excitatory fibers to the dorsal horn spinal cord neurons.Medial lemniscus: The medial lemniscus, also known as Reil's band or Reil's ribbon, is a large ascending bundle of heavily myelinated axons that decussate in the brain stem, specifically in the medulla. The medial lemniscus is formed by the crossings of internal arcuate fibers.SecobarbitalPulmonary hemorrhageClomethiazole

(1/921) Neurite outgrowth-regulating properties of GABA and the effect of serum on mouse spinal cord neurons in culture.

Time-lapse photography was used to examine the effects of gamma-aminobutyric acid (GABA) on the outgrowth and motility of neurites in cultures from mouse spinal cord. GABA at concentrations of 100, 10 and 1 microM caused significant inhibition of neurite outgrowth and the motility of growth cones was significantly reduced by treatment with 100 and 10 microM GABA. This effect was mimicked by the GABA(B) receptor agonist baclofen, whereas the GABA(A) receptor agonist muscimol had no effect. The effect of GABA on outgrowth and motility seems to be dependent on the type of serum employed. The results reported here were obtained only when heat-inactivated serum was used and not when non heat-inactivated serum was added to the culture medium. They suggest that GABA has a role in the regulation of process outgrowth within the embryonic mouse spinal cord.  (+info)

(2/921) Corticofugal amplification of facilitative auditory responses of subcortical combination-sensitive neurons in the mustached bat.

Recent studies on the bat's auditory system indicate that the corticofugal system mediates a highly focused positive feedback to physiologically "matched" subcortical neurons, and widespread lateral inhibition to physiologically "unmatched" subcortical neurons, to adjust and improve information processing. These findings have solved the controversy in physiological data, accumulated since 1962, of corticofugal effects on subcortical auditory neurons: inhibitory, excitatory, or both (an inhibitory effect is much more frequent than an excitatory effect). In the mustached bat, Pteronotus parnellii parnellii, the inferior colliculus, medial geniculate body, and auditory cortex each have "FM-FM" neurons, which are "combination-sensitive" and are tuned to specific time delays (echo delays) of echo FM components from the FM components of an emitted biosonar pulse. FM-FM neurons are more complex in response properties than cortical neurons which primarily respond to single tones. In the present study, we found that inactivation of the entire FM-FM area in the cortex, including neurons both physiologically matched and unmatched with subcortical FM-FM neurons, on the average reduced the facilitative responses to paired FM sounds by 82% for thalamic FM-FM neurons and by 66% for collicular FM-FM neurons. The corticofugal influence on the facilitative responses of subcortical combination-sensitive neurons is much larger than that on the excitatory responses of subcortical neurons primarily responding to single tones. Therefore we propose the hypothesis that, in general, the processing of complex sounds by combination-sensitive neurons more heavily depends on the corticofugal system than that by single-tone sensitive neurons.  (+info)

(3/921) Selective pruning of more active afferents when cat visual cortex is pharmacologically inhibited.

Activity-dependent competition is thought to guide the normal development of specific patterns of neural connections. Such competition generally favors more active inputs, making them larger and stronger, while less active inputs become smaller and weaker. We pharmacologically inhibited the activity of visual cortical cells and measured the three-dimensional structure of inputs serving the two eyes when one eye was occluded. The more active inputs serving the open eye actually became smaller than the deprived inputs from the occluded eye, which were similar to those in normal animals. These findings demonstrate in vivo that it is not the amount of afferent activity but the correlation between cortical and afferent activity that regulates the growth or retraction of these inputs.  (+info)

(4/921) Cholinergic and GABAergic regulation of nitric oxide synthesis in the guinea pig ileum.

Nitric oxide (NO) synthesis was examined in intact longitudinal muscle-myenteric plexus preparations of the guinea pig ileum by determining the formation of [3H]citrulline during incubation with [3H]arginine. Spontaneous [3H]citrulline production after 30 min was 80-90 dpm/mg, which constituted approximately 1% of the tissue radioactivity. Electrical stimulation (10 Hz) led to a threefold increase in [3H]citrulline formation. Removal of calcium from the medium or addition of NG-nitro-L-arginine strongly inhibited both spontaneous and electrically induced production of [3H]citrulline. TTX reduced the electrically induced but not spontaneous [3H]citrulline formation. The electrically induced formation of [3H]citrulline was diminished by (+)-tubocurarine and mecamylamine and enhanced by scopolamine, which suggests that endogenous ACh inhibits, via muscarinic receptors, and stimulates, via nicotinic receptors, the NO synthesis in the myenteric plexus. The GABAA receptor agonist muscimol and GABA also reduced the electrically evoked formation of [3H]citrulline, whereas baclofen was without effect. Bicuculline antagonized the inhibitory effect of GABA. It is concluded that nitrergic myenteric neurons are equipped with GABAA receptors, which mediate inhibition of NO synthesis.  (+info)

(5/921) RVLM and raphe differentially regulate sympathetic outflows to splanchnic and brown adipose tissue.

To determine whether neurons in the rostral raphe pallidus (RPa) specifically control the sympathetic nerve activity to brown adipose tissue (BAT SNA), thereby regulating adipocyte metabolism and BAT thermogenesis, the responses in BAT SNA to disinhibition of RPa neurons and to disinhibition of neurons in the vasomotor region of the rostral ventrolateral medulla (RVLM) were compared with those in splanchnic (Spl) SNA, which primarily regulates visceral vasoconstriction. In urethan-chloralose-anesthetized ventilated rats, both acute hypothermia and microinjection of bicuculline into RPa produced significantly larger increases in BAT SNA (542 and 1,949% of control) than in Spl SNA (19 and 24% of control). The enhanced burst discharge in BAT SNA was not coherent with that in Spl SNA or with the arterial pressure (AP) at any frequency except the central respiratory frequency. Microinjections of bicuculline into RVLM evoked increases in Spl SNA (86% of control) and AP (32 mmHg), but reduced BAT SNA to low, normothermic levels. Microinjections of muscimol into RVLM reduced Spl SNA (-82% of control) and AP (-59 mmHg), but did not prevent the increase in BAT SNA after disinhibition of RPa neurons. These results indicate that the neural networks generating BAT SNA in response to disinhibition of RPa neurons are independent of those generating basal Spl SNA and support a model in which sympathetic outflow to tissues involved in thermoregulation and metabolism is regulated by central pathways, including neurons in RPa, that are distinct from those involved in the sympathetic control of the cardiovascular system.  (+info)

(6/921) Effect of reversible inactivation of macaque lateral intraparietal area on visual and memory saccades.

Previous studies from our laboratory identified a parietal eye field in the primate lateral intraparietal sulcus, the lateral intraparietal area (area LIP). Here we further explore the role of area LIP in processing saccadic eye movements by observing the effects of reversible inactivation of this area. One to 2 microl of muscimol (8 mg/ml) were injected at locations where saccade-related activities were recorded for each lesion experiment. After the muscimol injection we observed in two macaque monkeys consistent effects on both the metrics and dynamics of saccadic eye movements at many injection sites. These effects usually took place within 10-30 min and disappeared after 5-6 h in most cases and certainly when tested the next day. After muscimol injection memory saccades directed toward the contralesional and upper space became hypometric, and in one monkey those to the ipsilesional space were slightly but significantly hypermetric. In some cases, the scatter of the end points of memory saccades was also increased. On the other hand, the metrics of visual saccades remained relatively intact. Latency for both visual and memory saccades toward the contralesional space was increased and in many cases displayed a higher variance after muscimol lesion. At many injection sites we also observed an increase of latency for visual and memory saccades toward the upper space. The peak velocities for memory saccades toward the contralesional space were decreased after muscimol injection. The peak velocities of visual saccades were not significantly different from those of the controls. The duration of saccadic eye movements either to the ipsilesional or contralesional space remained relatively the same for both visual and memory saccades. Overall these results demonstrated that we were able to selectively inactivate area LIP and observe effects on saccadic eye movements. Together with our previous recording studies these results futher support the view that area LIP plays a direct role in processing incoming sensory information to program saccadic eye movements. The results are consistent with our unit recording data and microstimulation studies, which suggest that area LIP represents contralateral space and also has a bias for the upper visual field.  (+info)

(7/921) Reacquisition deficits in prism adaptation after muscimol microinjection into the ventral premotor cortex of monkeys.

A small amount of muscimol (1 microl; concentration, 5 microg/microl) was injected into the ventral and dorsal premotor cortex areas (PMv and PMd, respectively) of monkeys, which then were required to perform a visually guided reaching task. For the task, the monkeys were required to reach for a target soon after it was presented on a screen. While performing the task, the monkeys' eyes were covered with left 10 degrees, right 10 degrees, or no wedge prisms, for a block of 50-100 trials. Without the prisms, the monkeys reached the targets accurately. When the prisms were placed, the monkeys initially misreached the targets because the prisms displaced the visual field. Before the muscimol injection, the monkeys adapted to the prisms in 10-20 trials, judging from the horizontal distance between the target location and the point where the monkey touched the screen. After muscimol injection into the PMv, the monkeys lost the ability to readapt and touched the screen closer to the location of the targets as seen through the prisms. This deficit was observed at selective target locations, only when the targets were shifted contralaterally to the injected hemisphere. When muscimol was injected into the PMd, no such deficits were observed. There were no changes in the reaction and movement times induced by muscimol injections in either area. The results suggest that the PMv plays an important role in motor learning, specifically in recalibrating visual and motor coordinates.  (+info)

(8/921) Muscimol-induced inactivation of monkey frontal eye field: effects on visually and memory-guided saccades.

Muscimol-induced inactivation of the monkey frontal eye field: effects on visually and memory-guided saccades. Although neurophysiological, anatomic, and imaging evidence suggest that the frontal eye field (FEF) participates in the generation of eye movements, chronic lesions of the FEF in both humans and monkeys appear to cause only minor deficits in visually guided saccade generation. Stronger effects are observed when subjects are tested in tasks with more cognitive requirements. We tested oculomotor function after acutely inactivating regions of the FEF to minimize the effects of plasticity and reallocation of function after the loss of the FEF and gain more insight into the FEF contribution to the guidance of eye movements in the intact brain. Inactivation was induced by microinjecting muscimol directly into physiologically defined sites in the FEF of three monkeys. FEF inactivation severely impaired the monkeys' performance of both visually guided and memory-guided saccades. The monkeys initiated fewer saccades to the retinotopic representation of the inactivated FEF site than to any other location in the visual field. The saccades that were initiated had longer latencies, slower velocities, and larger targeting errors than controls. These effects were present both for visually guided and for memory-guided saccades, although the memory-guided saccades were more disrupted. Initially, the effects were restricted spatially, concentrating around the retinotopic representation at the center of the inactivated site, but, during the course of several hours, these effects spread to flanking representations. Predictability of target location and motivation of the monkey also affected saccadic performance. For memory-guided saccades, increases in the time during which the monkey had to remember the spatial location of a target resulted in further decreases in the accuracy of the saccades and in smaller peak velocities, suggesting a progressive loss of the capacity to maintain a representation of target location in relation to the fovea after FEF inactivation. In addition, the monkeys frequently made premature saccades to targets in the hemifield ipsilateral to the injection site when performing the memory task, indicating a deficit in the control of fixation that could be a consequence of an imbalance between ipsilateral and contralateral FEF activity after the injection. There was also a progressive loss of fixation accuracy, and the monkeys tended to restrict spontaneous visual scanning to the ipsilateral hemifield. These results emphasize the strong role of the FEF in the intact monkey in the generation of all voluntary saccadic eye movements, as well as in the control of fixation.  (+info)



baclofen


  • Intrategmental infusion of tetradotoxin (1 μM), muscimol (20 μM) or baclofen (50 μM) decreased extracellular dopamine in the PFC. (aspetjournals.org)
  • Accordingly, following extinction from long-access methamphetamine self-administration, rats were bilaterally microinjected with either a combination of the GABA agonists baclofen/muscimol or vehicle (artificial cerebrospinal fluid) into the infralimbic or prelimbic subcompartments of the medial prefrontal cortex or into the shell or core subcompartments of the nucleus accumbens. (omicsonline.org)

GABA


  • In contrast, rats that received bilateral, intra-entorhinal infusions of muscimol, a gamma-aminobutyric acid(a) (GABA(a)) agonist, before either training or testing spent equal amounts of time in the two arms, indicating that they failed to acquire and were unable to express this information. (biomedsearch.com)

effects


  • Monkshood and muscimol counter the effects of anticholinergenics. (shroomery.org)