Hazard
Neurotoxic; causes motor depression, ataxia, changes in mood, perceptions and feelings.
Description
Ibotenic acid (60573-88-8) is a conformationally restricted analog of glutamate which occurs naturally in Amanita mascaria and related mushrooms.? It is a non-specific glutamate receptor (both NMDA and mGluR) agonist.1 May be used to induce hippocampal lesioning in rat neurodegeneration models.2,3 Induces lesions in the subiculum in a mouse model of Alzheimer’s disease.4
Chemical Properties
Crystalline solid; forms monohydrate; mp151°C (303.8°F) (anhydrous), 145°C (293°F)(monohydrate); soluble in water and alcohol.
Uses
Ibotenic acid is a neuroexcitatory amino acid originally isolated from Amanita species that functions as a NMDA and metabotropic glutamate receptor agonist. As a neurotoxin, ibotenic acid is often used to induce brain lesions in animals that model cognitive dysfunctions resulting from neurodegenerative diseases, traumatic brain injury, and stroke.
Uses
Neurobiological tool.
Preparation
Isolated from the Japanese fly mushroom. The acid can be produced synthetically.
Health Hazard
Ibotenic acid is a potent neurologic aminoacid. It exhibits neuroexcitatory activity andcauses sedative actions on spinal neurons.High doses can cause sleep, hallucinations,distorted perceptions, and nausea. In humansthe symptoms above may be manifested fromingestion of 6–8 mg of ibotenic acid.
LD50 value, oral (mice): 38 mg/kg
LD50 value, intraperitoneal (mice): 15 mg/kg.
Biological Activity
NMDA and metabotropic glutamate receptor agonist.
Biochem/physiol Actions
Non-selective agonist with preference for NMDA glutamate receptors; neurotoxin; neuroexcitatory amino acid originally isolated from Amanita species.
storage
Desiccate at -20°C
Purification Methods
It has been converted to the ammonium salt (m 121-123o dec) dissolved in H2O, passed through an Amberlite IR 120 resin (H+ form) and eluted with H2O. The acidic fractions are collected, evaporated to dryness and the residue recrystallises from H2O as the monohydrate (m 144-146o). The anhydrous acid is obtained by making a slurry with MeOH, decanting and evaporating to dryness, and repeating the process twice more to give the anhydrous acid (m 151-152o). Recrystallisation from H2O gives the monohydrate. [Nakamura Chem Pharm Bull Jpn 19 46 1971.] The ethyl ester forms needles when crystallised from a small volume of Et2O and has m 78-79o and IR (CHCl3) with
max 35002300 (OH), 1742 (ester C=O), 1628, 1528cm-1, and UV with λmax (EtOH) at 206nm (ε 7,080).
The hydrazide has m 174-175o (from MeOH) with IR (KBr) 1656 (C=O)cm-1.
References
1) Nakanishi (1992), Molecular diversity of glutamate receptors and implications for brain function; Science 258 597
2) Jarrard (1989), On the use of ibotenic acid to lesion selectively different components of the hippocampal formation; J. Neurosci. Methods 29 251
3) Isacson and Peschanski (1992), Is there capacity for anatomical and functional repair in the adult somatosensory thalamus?; Exp. Neurol. 115 173
4) George et al. (2014), Lesion of the subiculum reduces the spread of amyloid beta pathology to interconnected brain regions in a mouse model of Alzheimer’s disease; Acta Neuropathol. Commun. 2 17
