| gamma aminobutyric acid | <biochemistry> An important amino acid which functions as the most prevalent inhibitory neurotransmitter in the central nervous system. Gamma aminobutyric acid works in partnership with a derivative of Vitamin B-6, pyridoxine, to cross from the axons to the dendrites through the synaptic cleft, in response to an electrical signal in the neuron and inhibits message transmission. This helps control the nerve cells from firing too fast, which would overload the system. The action of gamma aminobutyric acid decreases epileptic seizures and muscle spasms by inhibiting electrical signals in this manner. Studies have shown that the site of action in the brain of benzodiazepams, including Valium, is directly coupled to the brain receptor for gamma aminobutyric acid. Acronym: GABA (05 Jan 1998) |
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| gamma aminobutyric acid receptor | <physiology> Ligand gated chloride ion channel forming receptor opened by gamma aminobutyric acid. Two distinct types: A and B. A receptor: One of a family of neurotransmitter receptors with fast intrinsic ion channels that includes the glycine receptor and the nicotinic acetylcholine receptor. Distinct from another major receptor family, the muscarininc acetylcholine receptor and rhodopsin, with no intrinsic ion channel. The A receptor is specifically blocked by bicuculline. It consists of two pairs of protein chains forming an A2B2 complex, the A chains bind benzodiazepine and the B chains bind GABA. The 4 subunits are thought to form a tight group with the chloride channel in the middle. There is considerable similarity between the amino acid sequences of the receptor subunits and those of the nicotinic acetylcholine receptor suggesting that both receptors are derived from some evolutionary ancestor. See: amino acid receptor superfamily. B receptor: Brain receptor (80 kD) for the inhibitory neurotransmitter gamma amino butyric acid. Differs from the A receptor both in agonist specificity (baclofen is a specific agonist) and its effects on cells. It modulates intracellular calcium levels through a Go mediated effect on N type calcium channels and also lowers intracellular cAMP levels by an effect on adenylyl cyclase, thereby reducing the secretion of catecholamines. (05 Jan 1998) |
| d-aminobutyric acid | <enzyme> An enzyme catalyzing the reversible transfer of an amino group from d-aminobutyric acid to 2-oxoglutarate, thus forming a L-glutamic acid and succinate saemialdehyde. An important step in the catabolism of d-aminobutyric acid. (05 Mar 2000) |
| aminobutyric acids | <chemistry> Aliphatic four carbon acids substituted in any position(s) with amino group(s). They are found in most living things. The best known is gaba. (12 Dec 1998) |
| administration, oral | The giving of drugs, chemicals, or other substances by mouth. (12 Dec 1998) |
| cancer, oral | Cancer of the mouth area. A sore in the mouth that does not heal can be a warning sign of oral cancer. A biopsy is the only to know whether as abnormal area in the oral cavity is cancer. Oral cancer is caused by tobacco (smoking and chewing) and alcohol use. Surgery to remove the tumour in the mouth is the usual treatment for patients with oral cancer. (12 Dec 1998) |
| candidiasis, oral | Infection of the mucous membranes of the mouth by a fungus of the genus candida. (12 Dec 1998) |
| canine oral papilloma | Warts affecting mucous membranes of young dogs; caused by a papillomavirus. (05 Mar 2000) |
| magnesia and alumina oral suspension | A mixture of magnesium hydroxide and variable amounts of aluminum oxide; used as an antacid. (05 Mar 2000) |
| pathology, oral | A dental specialty concerned with pathology of the oral cavity. (12 Dec 1998) |
| pharyngo-oral | Relating to the pharynx and the mouth; oropharyngeal. Origin: pharyngo-+ L. Os (or-), mouth (05 Mar 2000) |
| combination oral contraceptive | A mixture of a steroid having progestational activity and an oestrogen. (05 Mar 2000) |
| contraceptives, oral | Compounds, usually hormonal, taken orally in order to block ovulation and prevent the occurrence of pregnancy. The hormones are generally oestrogen or progesterone or both. (12 Dec 1998) |
| contraceptives, oral, combined | Fixed drug combinations administered orally for contraceptive purposes. (12 Dec 1998) |
| contraceptives, oral, hormonal | Oral contraceptives which owe their effectiveness to hormonal preparations. (12 Dec 1998) |