GABAA receptorDISPLAYTITLE:GABAA receptor The GABAA receptor (GABAAR) is an ionotropic receptor and ligand-gated ion channel. Its endogenous ligand is γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system. Upon opening, the GABAA receptor on the postsynaptic cell is selectively permeable to chloride ions (Cl−) and, to a lesser extent, bicarbonate ions (HCO3−). Depending on the membrane potential and the ionic concentration difference, this can result in ionic fluxes across the pore.
GABA receptorThe GABA receptors are a class of receptors that respond to the neurotransmitter gamma-aminobutyric acid (GABA), the chief inhibitory compound in the mature vertebrate central nervous system. There are two classes of GABA receptors: GABAA and GABAB. GABAA receptors are ligand-gated ion channels (also known as ionotropic receptors); whereas GABAB receptors are G protein-coupled receptors, also called metabotropic receptors.
AnxietyAnxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different from fear in that fear is defined as the emotional response to a real threat, whereas anxiety is the anticipation of a future threat. It is often accompanied by nervous behavior such as pacing back and forth, somatic complaints, and rumination. Anxiety is a feeling of uneasiness and worry, usually generalized and unfocused as an overreaction to a situation that is only subjectively seen as menacing.
Glycine receptorThe glycine receptor (abbreviated as GlyR or GLR) is the receptor of the amino acid neurotransmitter glycine. GlyR is an ionotropic receptor that produces its effects through chloride current. It is one of the most widely distributed inhibitory receptors in the central nervous system and has important roles in a variety of physiological processes, especially in mediating inhibitory neurotransmission in the spinal cord and brainstem.
Receptor (biochemistry)In biochemistry and pharmacology, receptors are chemical structures, composed of protein, that receive and transduce signals that may be integrated into biological systems. These signals are typically chemical messengers which bind to a receptor and produce physiological responses such as change in the electrical activity of a cell. For example, GABA, an inhibitory neurotransmitter inhibits electrical activity of neurons by binding to GABA_A receptors.
Nicotinic acetylcholine receptorNicotinic acetylcholine receptors, or nAChRs, are receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral nervous system, muscle, and many other tissues of many organisms. At the neuromuscular junction they are the primary receptor in muscle for motor nerve-muscle communication that controls muscle contraction.
Anxiety disorderAnxiety disorders are a cluster of mental disorders characterized by significant and uncontrollable feelings of anxiety and fear such that a person's social, occupational, and personal function are significantly impaired. Anxiety may cause physical and cognitive symptoms, such as restlessness, irritability, easy fatiguability, difficulty concentrating, increased heart rate, chest pain, abdominal pain, and a variety of other symptoms that may vary based on the individual.
Ventral tegmental areaThe ventral tegmental area (VTA) (tegmentum is Latin for covering), also known as the ventral tegmental area of Tsai, or simply ventral tegmentum, is a group of neurons located close to the midline on the floor of the midbrain. The VTA is the origin of the dopaminergic cell bodies of the mesocorticolimbic dopamine system and other dopamine pathways; it is widely implicated in the drug and natural reward circuitry of the brain.
Social anxietySocial anxiety is the anxiety and fear specifically linked to being in social settings (i.e., interacting with others). Some categories of disorders associated with social anxiety include anxiety disorders, mood disorders, autism spectrum disorders, eating disorders, and substance use disorders. Individuals with higher levels of social anxiety often avert their gazes, show fewer facial expressions, and show difficulty with initiating and maintaining a conversation.
BenzodiazepineBenzodiazepines (BZD, BDZ, BZs), colloquially called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, insomnia, and seizures. The first benzodiazepine, chlordiazepoxide (Librium), was discovered accidentally by Leo Sternbach in 1955 and was made available in 1960 by Hoffmann–La Roche, who soon followed with diazepam (Valium) in 1963.
Nicotinic agonistA nicotinic agonist is a drug that mimics the action of acetylcholine (ACh) at nicotinic acetylcholine receptors (nAChRs). The nAChR is named for its affinity for nicotine. Examples include nicotine (by definition), acetylcholine (the endogenous agonist of nAChRs), choline, epibatidine, lobeline, varenicline and cytisine. Nicotine has been known for centuries for its intoxicating effect. It was first isolated in 1828 from the tobacco plant by German chemists Posselt and Reimann.
AddictionAddiction is generally a neuropsychological disorder defining pervasive and intense urge to engage in maladaptive behaviors providing immediate sensory rewards (e.g. consuming drugs, excessively gambling), despite their harmful consequences. Dependence is generally an addiction that can involve withdrawal issues. Addictive disorder is a category of mental disorders defining important intensities of addictions or dependences, which induce functional disabilities. There are no agreed definitions on these terms – see section on 'definitions'.
AnxiolyticAn anxiolytic (ˌæŋksiəˈlɪtɪk,_ˌæŋksioʊ-; also antipanic or anti-anxiety agent) is a medication or other intervention that reduces anxiety. This effect is in contrast to anxiogenic agents which increase anxiety. Anxiolytic medications are used for the treatment of anxiety disorders and their related psychological and physical symptoms. Anxiety is a naturally-occurring emotion and response. When anxiety levels exceed the tolerability of a person, anxiety disorders may occur.
Social anxiety disorderSocial anxiety disorder (SAD), also known as social phobia, is an anxiety disorder characterized by sentiments of fear and anxiety in social situations, causing considerable distress and impairing ability to function in at least some aspects of daily life. These fears can be triggered by perceived or actual scrutiny from others. Individuals with social anxiety disorder fear negative evaluations from other people. Physical symptoms often include excessive blushing, excessive sweating, trembling, palpitations, and nausea.
Generalized anxiety disorderGeneralized anxiety disorder (GAD) is a mental and behavioral disorder, specifically an anxiety disorder characterized by excessive, uncontrollable and often irrational worry about events or activities. Worry often interferes with daily functioning, and individuals with GAD are often overly concerned about everyday matters such as health, finances, death, family, relationship concerns, or work difficulties. Symptoms may include excessive worry, restlessness, trouble sleeping, exhaustion, irritability, sweating, and trembling.
Benzodiazepine withdrawal syndromeBenzodiazepine withdrawal syndrome, often abbreviated to benzo withdrawal or BZD withdrawal, is the cluster of signs and symptoms that may emerge when a person who has been taking benzodiazepines as prescribed develops a physical dependence on them and then reduces the dose or stops taking them without a safe taper schedule.
Separation anxiety disorderSeparation anxiety disorder (SAD) is an anxiety disorder in which an individual experiences excessive anxiety regarding separation from home and/or from people to whom the individual has a strong emotional attachment (e.g., a parent, caregiver, significant other, or siblings). Separation anxiety is a natural part of the developmental process. It is most common in infants and little children, typically between the ages of six to seven months to three years, although it may pathologically manifest itself in older children, adolescents and adults.
Cys-loop receptorThe Cys-loop ligand-gated ion channel superfamily is composed of nicotinic acetylcholine, GABAA, GABAA-ρ, glycine, 5-HT3, and zinc-activated (ZAC) receptors. These receptors are composed of five protein subunits which form a pentameric arrangement around a central pore. There are usually 2 alpha subunits and 3 other beta, gamma, or delta subunits (some consist of 5 alpha subunits). The name of the family refers to a characteristic loop formed by 13 highly conserved amino acids between two cysteine (Cys) residues, which form a disulfide bond near the N-terminal extracellular domain.
AlcoholismAlcoholism is, broadly, any drinking of alcohol that results in significant mental or physical health problems. Because there is disagreement on the definition of the word alcoholism, it is not a recognized diagnostic entity, and the use of alcoholism terminology is discouraged due to its heavily stigmatized connotations. Predominant diagnostic classifications are alcohol use disorder (DSM-5) or alcohol dependence (ICD-11); these are defined in their respective sources.
Allosteric modulatorIn pharmacology and biochemistry, allosteric modulators are a group of substances that bind to a receptor to change that receptor's response to stimuli. Some of them, like benzodiazepines or alcoholic beverages, function as psychoactive drugs. The site that an allosteric modulator binds to (i.e., an allosteric site) is not the same one to which an endogenous agonist of the receptor would bind (i.e., an orthosteric site). Modulators and agonists can both be called receptor ligands.
