Y-Aminobutyric acid, 254

Valerian is used in the short-term treatment of insomnia characterized by difficulty in falling asleep and poor sleep quality. Valeriana officinalis L. inhibits reuptake of and stimulates the release of y-aminobutyric acid (GABA), contributing to its sedative properties. 

FIG U RE 65.2 Schematic model of the GABAa receptor. The receptor spans the cell membrane. GABA binds to the outside of the receptor, causing an influx of Cl ions through the channel. Benzodiazepines and barbiturates interact with different recognition sites on the receptor and increase the effectiveness of GABA. 

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Lindane is used predominately as a seed dressing and soil insecticide, for the control of ectoparasites of humans and domestic animals, for the control of locusts and grasshoppers, and as a residual spray to control the Anopheles vectors of malaria. Because of its relatively high volatility it is useful to control wood-boring insects of timber, fmit trees, and ornamental plants. The mode of action is not well understood but is thought to be competitive blocking of the y-aminobutyric acid (GABA) transmitter of synaptic nerve transmission. 

Mode of Motion. The cyclodienes, like lindane and toxaphene, affect the nerve axon produciag hyperactivity, convulsions, prostration, and death. The biochemical lesion is the competitive inhibition of the y-aminobutyric acid (GABA) neurotransmitter binding site of the nerve axon. Spray workers with lengthy exposure to dieldrin have suffered from prolonged and repeated central nervous system disturbances produciag epileptiform coavulsioas. Similar disturbances occurred ia workers heavily exposed to chlordecoae. 

Avermectins and Ivermectin. The avermectias are pentacycHc lactones isolated from fermentation products of Streptomjces avermitilis and ivermectin is a semisynthetic chemical, 22,23-dihydroavermectia (46). Ivermectin is effective in very low doses for the control of red spider mites on deciduous fmits, in baits for the control of imported fire ants, and as a parasiticide for Onchocerca volvulus in humans and for catde gmbs. These insecticides appear to function as agonists for the neuroinhibitory transmitter y-aminobutyric acid (GABA) (see Antiparasitic agents, avermectins). 

Strong acids or bases catalyze the hydrolysis of 2-pyrrohdinone to 4-aminobutanoic acid [y-aminobutyric acid [56-12-2] (GABA)]. GABA is involved in the functioning of the brain and nervous system and is of considerable interest as a potential dietary supplement (60). 

Another class of therapeutic agents is used for the treatment of certain genetic diseases or other enzymatic disorders caused by the dysfunction or absence of one particular enzyme. This often leads to an unwanted accumulation or imbalance of metaboUtes in the organism. Eor example, some anticonvulsive agents are inhibitors for y-aminobutyric acid aminotransferase [9037-67-6]. An imbalance of two neurotransmitters, glutamate and y-aminobutyric acid, is responsible for the symptoms. Inhibition of the enzyme leads to an increase of its substrate y-aminobutyric acid, decreasing the imbalance and subsequently relieving the symptoms of the disease. 

Aminobutanoic acid known as y-aminobutyric acid (GABA), it is a y-amino acid and is involved in the transmission of nerve impulses... 

One of the amino acids in Table 27.1 is the biological precursor to y-aminobutyric acid (4-aminobutanoic acid), which it forms by a decarboxylation reaction. Which amino acid is this ... 

Certain amino acids and their derivatives, although not found in proteins, nonetheless are biochemically important. A few of the more notable examples are shown in Figure 4.5. y-Aminobutyric acid, or GABA, is produced by the decarboxylation of glutamic acid and is a potent neurotransmitter. Histamine, which is synthesized by decarboxylation of histidine, and serotonin, which is derived from tryptophan, similarly function as neurotransmitters and regulators. /3-Alanine is found in nature in the peptides carnosine and anserine and is a component of pantothenic acid (a vitamin), which is a part of coenzyme A. Epinephrine (also known as adrenaline), derived from tyrosine, is an important hormone. Penicillamine is a constituent of the penicillin antibiotics. Ornithine, betaine, homocysteine, and homoserine are important metabolic intermediates. Citrulline is the immediate precursor of arginine. 

Sleep and its modulation by N- and N,0-heterocyclic drugs that affect y-aminobutyric acid (GABA) receptor function 99AG(E)2852. 

GABA (y-aminobutyric acid) is an amino acid with mostly inhibitory functions in the mammalian central nervous system. Structures involved in releasing or binding GABA as a neurotransmitter constitute the GABAergic system. The GABAergic system is involved... 

There is also evidence for ATP as a cotransmitter with y-aminobutyric acid or with glutamate, serotonin, NA or dopamine in nerves in the central nervous system. 

Tetanus is a disease caused by the release of neurotoxins from the anaerobic, spore-forming rod Clostridium tetani. The clostridial protein, tetanus toxin, possesses a protease activity which selectively degrades the pre-synaptic vesicle protein synaptobrevin, resulting in a block of glycine and y-aminobutyric acid (GABA) release from presynaptic terminals. Consistent with the loss of neurogenic motor inhibition, symptoms of tetanus include muscular rigidity and hyperreflexia. The clinical course is characterized by increased muscle tone and spasms, which first affect the masseter muscle and the muscles of the throat, neck and shoulders. Death occurs by respiratory failure or heart failure. 

Amiloride-sensitive Na+ Channel y-Aminobutyric Acid (GABA) Aminoglycosides Aminopeptidase AMP, Cyclic... 

Nofe. AMPA = amino-3-hydroxy-5--methyl-4-isoxazole propionate GABA=y-aminobutyric acid. 

Succinic semialdehyde (SSA) is synthesized in the mitochondria through transamination of y-aminobutyric acid (GABA) by GABA transaminase (GABA-T). Most of the SSA is oxidized by SSA dehydrogenase (SSA-DH) to form succinate, which is used for energy metabolism and results in the end products CO2 + H2O, which are expired. A small portion of SSA (<2%) is converted by SSA reductase (SSA-R) in the cytosol to GHB. GHB may also be oxidized back to SSA by GHB dehydrogenase (GHB-DH). 

Severe withdrawal symptoms, including insomnia, irritability, agitation, withdrawal seizures, and delirium, have been described in both mice and humans chronically exposed to the anesthetics nitrous oxide, ether, and isoflurane (Arnold et al. 1993 Delteil et al. 1974 Deniker et al. 1972 Harper et al. 1980 Smith et al. 1979 Tobias 2000). These symptoms were controlled with the administration of y-aminobutyric acid (GABA)-ergic agents such as pentobarbital, midazolam, and diazepam (Arnold et al. 1993 Hughes et al. 1993). 

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