Beside drugs, toxic agents act while modifying directly or indirectly activity of GABA or glutamate. We will give some examples of them:
GABAmimetic agents
Muscimol
isolated from mushrooms of type fly agaric, Amanita muscaria and Amanita pantherina (which contain other biologically active compounds than muscinol)
muscinol is chemically close to ibotenic acid
agonist of GABA-A receptors
is used as pharmacological reagent
GABA antagonists
Picrotoxine
found in certain plants
is an antagonist of GABA-A receptors
convulsive agent
Bicuculline
found in certain plants
antagonist of GABA-A receptors
convulsive agent
Alpha-thujone
present in essential oil of wormwood, Artemisia absinthium, which was used as drink, in particular in Paris about 1900, before being prohibited
antagonist of GABA-A receptors
has stimulant and convulsive effects
Fipronil
Noncompetitive inhibitor of GABA, fipronil inhibits chloride entry into cells of insects but has little or no effect in vertebrates. This inhibition of chloride entry creates a cellular depolarization in insects. It is used in external applications against fleas in dog and cat and ticks in dog.
Glycine antagonists
Strychnine
alkaloid present in vomic nut, Strychnos nux-vomica
is an antagonist of glycine receptors ,
was formerly used in medicine as stimulant
was used as mole killer
in human poisoning causes: muscular hyperreflexia, anxiety, seizures, tensions, poisoning which can be treated by a benzodiazepine.
Glutaminomimetic
Called sometimes EAA for Excitory Amino Acids.
Domoic a cid
is an agonist of ionotropic receptors of glutamate
can contaminate certain edible shells where it could be produced by microorganisms. Consumption of these shells can cause poisoning with various disorders such as loss of memory
Oxalyl diaminopropionic acid
Present in various plants, of which Lathyrus sativus; poisoning by these plants causes lathyrism.