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.GABA-A Receptor Agonists: Endogenous compounds and drugs that bind to and activate GABA-A RECEPTORS.GABA-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.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.Flumazenil: A potent benzodiazepine receptor antagonist. Since it reverses the sedative and other actions of benzodiazepines, it has been suggested as an antidote to benzodiazepine overdoses.Pregnanolone: A pregnane found in the urine of pregnant women and sows. It has anesthetic, hypnotic, and sedative properties.GABA Agonists: Endogenous compounds and drugs that bind to and activate GAMMA-AMINOBUTYRIC ACID receptors (RECEPTORS, GABA).GABA Antagonists: Drugs that bind to but do not activate GABA RECEPTORS, thereby blocking the actions of endogenous GAMMA-AMINOBUTYRIC ACID and GABA RECEPTOR AGONISTS.gamma-Aminobutyric Acid: The most common inhibitory neurotransmitter in the central nervous system.Receptors, GABA: Cell-surface proteins that bind GAMMA-AMINOBUTYRIC ACID with high affinity and trigger changes that influence the behavior of cells. GABA-A receptors control chloride channels formed by the receptor complex itself. They are blocked by bicuculline and usually have modulatory sites sensitive to benzodiazepines and barbiturates. GABA-B receptors act through G-proteins on several effector systems, are insensitive to bicuculline, and have a high affinity for L-baclofen.PyridazinesGABA Modulators: Substances that do not act as agonists or antagonists but do affect the GAMMA-AMINOBUTYRIC ACID receptor-ionophore complex. GABA-A receptors (RECEPTORS, GABA-A) appear to have at least three allosteric sites at which modulators act: a site at which BENZODIAZEPINES act by increasing the opening frequency of GAMMA-AMINOBUTYRIC ACID-activated chloride channels; a site at which BARBITURATES act to prolong the duration of channel opening; and a site at which some steroids may act. GENERAL ANESTHETICS probably act at least partly by potentiating GABAergic responses, but they are not included here.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.Bicuculline: An isoquinoline alkaloid obtained from Dicentra cucullaria and other plants. It is a competitive antagonist for GABA-A receptors.Tissue Inhibitor of Metalloproteinases: A family of secreted protease inhibitory proteins that regulates the activity of SECRETED MATRIX METALLOENDOPEPTIDASES. They play an important role in modulating the proteolysis of EXTRACELLULAR MATRIX, most notably during tissue remodeling and inflammatory processes.Protein Subunits: Single chains of amino acids that are the units of multimeric PROTEINS. Multimeric proteins can be composed of identical or non-identical subunits. One or more monomeric subunits may compose a protomer which itself is a subunit structure of a larger assembly.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.Hemiplegia: Severe or complete loss of motor function on one side of the body. This condition is usually caused by BRAIN DISEASES that are localized to the cerebral hemisphere opposite to the side of weakness. Less frequently, BRAIN STEM lesions; cervical SPINAL CORD DISEASES; PERIPHERAL NERVOUS SYSTEM DISEASES; and other conditions may manifest as hemiplegia. The term hemiparesis (see PARESIS) refers to mild to moderate weakness involving one side of the body.Neural Inhibition: The function of opposing or restraining the excitation of neurons or their target excitable cells.Hippocampus: A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Receptors, N-Methyl-D-Aspartate: A class of ionotropic glutamate receptors characterized by affinity for N-methyl-D-aspartate. NMDA receptors have an allosteric binding site for glycine which must be occupied for the channel to open efficiently and a site within the channel itself to which magnesium ions bind in a voltage-dependent manner. The positive voltage dependence of channel conductance and the high permeability of the conducting channel to calcium ions (as well as to monovalent cations) are important in excitotoxicity and neuronal plasticity.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Mice, Inbred C57BLRNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.