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5-HT1A
The serotonin 1A receptor (or 5-HT1A receptor) is a subtype of serotonin receptor, or 5-HT receptor, that binds serotonin, also known as 5-HT, a neurotransmitter. 5-HT1A is expressed in the brain, spleen, and neonatal kidney. It is a G protein-coupled receptor (GPCR), coupled to the Gi protein, and its activation in the brain mediates hyperpolarisation and reduction of firing rate of the postsynaptic neuron. In humans, the serotonin 1A receptor is encoded by the HTR1A gene. Distribution The 5-HT1A receptor is the most widespread of all the 5-HT receptors. In the central nervous system, 5-HT1A receptors exist in the cerebral cortex, hippocampus, septum, amygdala, and raphe nucleus in high densities, while low amounts also exist in the basal ganglia and thalamus. The 5-HT1A receptors in the raphe nucleus are largely somatodendritic autoreceptors, whereas those in other areas such as the hippocampus are postsynaptic receptors. Function Neuromodulation 5-HT1A receptor ag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serotonin Receptor
5-HT receptors, 5-hydroxytryptamine receptors, or serotonin receptors, are a group of G protein-coupled receptor and ligand-gated ion channels found in the central and peripheral nervous systems. They mediate both excitatory and inhibitory neurotransmission. The serotonin receptors are activated by the neurotransmitter serotonin, which acts as their natural ligand. The serotonin receptors modulate the release of many neurotransmitters, including glutamate, GABA, dopamine, epinephrine / norepinephrine, and acetylcholine, as well as many hormones, including oxytocin, prolactin, vasopressin, cortisol, corticotropin, and substance P, among others. Serotonin receptors influence various biological and neurological processes such as aggression, anxiety, appetite, cognition, learning, memory, mood, nausea, sleep, and thermoregulation. They are the target of a variety of pharmaceutical and recreational drugs, including many antidepressants, antipsychotics, anorectics, antiemetics, gast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urapidil
Urapidil is a sympatholytic antihypertensive drug. It acts as an α1-adrenoceptor antagonist and as an 5-HT1A receptor agonist. Although an initial report suggested that urapidil was also an α2-adrenoceptor agonist, this was not substantiated in later studies that demonstrated it was devoid of agonist actions in the dog saphenous vein and the guinea-pig ileum. Unlike some other α1-adrenoceptor antagonists, urapidil does not elicit reflex tachycardia, and this may be related to its weak β1-adrenoceptor antagonist activity, as well as its effect on cardiac vagal drive. Urapidil is currently not approved by the U.S. Food and Drug Administration, but it is available in Europe. See also * Naftopidil Naftopidil (INN, marketed under the brand name Flivas) is a drug used in benign prostatic hypertrophy which acts as a selective α1-adrenergic receptor antagonist or alpha-1 blocker. See also * Urapidil Urapidil is a sympatholytic antihyp ... References {{Pipe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotransmitter
A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, any main body part or target cell, may be another neuron, but could also be a gland or muscle cell. Neurotransmitters are released from synaptic vesicles into the synaptic cleft where they are able to interact with neurotransmitter receptors on the target cell. The neurotransmitter's effect on the target cell is determined by the receptor it binds. Many neurotransmitters are synthesized from simple and plentiful precursors such as amino acids, which are readily available and often require a small number of biosynthetic steps for conversion. Neurotransmitters are essential to the function of complex neural systems. The exact number of unique neurotransmitters in humans is unknown, but more than 100 have been identified. Common neurotransmitters include glutamate, GABA, acetylcholine, glycine and norepinephrine. Mechanism and cycle Synthes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agonist
An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the agonist, while an inverse agonist causes an action opposite to that of the agonist. Etymology From the Greek αγωνιστής (agōnistēs), contestant; champion; rival < αγων (agōn), contest, combat; exertion, struggle < αγω (agō), I lead, lead towards, conduct; drive Types of agonists can be activated by either endogenous agonists (such as |
Serotonin
Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and vasoconstriction. Approximately 90% of the serotonin that the body produces is in the intestinal tract. Biochemically, the indoleamine molecule derives from the amino acid tryptophan, via the (rate-limiting) hydroxylation of the 5 position on the ring (forming the intermediate 5-hydroxytryptophan), and then decarboxylation to produce serotonin. Serotonin is primarily found in the enteric nervous system located in the gastrointestinal tract (GI tract). However, it is also produced in the central nervous system (CNS), specifically in the raphe nuclei located in the brainstem, Merkel cells located in the skin, pulmonary neuroendocrine cells and taste receptor cells in the tongue. Additionally, serotonin is stored in blood platelets and is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autoreceptor
An autoreceptor is a type of receptor located in the membranes of nerve cells. It serves as part of a negative feedback loop in signal transduction. It is only sensitive to the neurotransmitters or hormones released by the neuron on which the autoreceptor sits. Similarly, a heteroreceptor is sensitive to neurotransmitters and hormones that are not released by the cell on which it sits. A given receptor can act as either an autoreceptor or a heteroreceptor, depending upon the type of transmitter released by the cell on which it is embedded. Autoreceptors may be located in any part of the cell membrane: in the dendrites, the cell body, the axon, or the axon terminals. Canonically, a presynaptic neuron releases a neurotransmitter across a synaptic cleft to be detected by the receptors on a postsynaptic neuron. Autoreceptors on the presynaptic neuron will also detect this neurotransmitter and often function to control internal cell processes, typically inhibiting further release or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drug
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via insufflation (medicine), inhalation, drug injection, injection, smoking, ingestion, absorption (skin), absorption via a dermal patch, patch on the skin, suppository, or sublingual administration, dissolution under the tongue. In pharmacology, a drug is a chemical substance, typically of known structure, which, when administered to a living organism, produces a biological effect. A pharmaceutical drug, also called a medication or medicine, is a chemical substance used to pharmacotherapy, treat, cure, preventive healthcare, prevent, or medical diagnosis, diagnose a disease or to promote well-being. Traditionally drugs were obtained through extraction from medicinal plants, but more recently also by organic synthesis. Pharmaceutical drugs may be used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antihypertensive
Antihypertensives are a class of drugs that are used to treat hypertension (high blood pressure). Antihypertensive therapy seeks to prevent the complications of high blood pressure, such as stroke and myocardial infarction. Evidence suggests that reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34% and of ischaemic heart disease by 21%, and can reduce the likelihood of dementia, heart failure, and mortality from cardiovascular disease. There are many classes of antihypertensives, which lower blood pressure by different means. Among the most important and most widely used medications are thiazide diuretics, calcium channel blockers, ACE inhibitors, angiotensin II receptor antagonists (ARBs), and beta blockers. Which type of medication to use initially for hypertension has been the subject of several large studies and resulting national guidelines. The fundamental goal of treatment should be the prevention of the important endpoints of hypert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatholytic
A sympatholytic (or sympathoplegic) drug is a medication that opposes the downstream effects of postganglionic nerve firing in effector organs innervated by the sympathetic nervous system (SNS). They are indicated for various functions; for example, they may be used as antihypertensives. They are also used to treat anxiety, such as generalized anxiety disorder, panic disorder and PTSD. In some cases, such as with Guanfacine, they have also shown to be beneficial in the treatment of ADHD. Mechanisms of action Antiadrenergic agents inhibit the signals of epinephrine and norepinephrine. They are primarily postsynaptic adrenergic receptor antagonists (alpha and beta adrenergic receptor antagonists, or "blockers"), inhibiting the downstream cellular signaling pathways of adrenergic receptors. However, there are exceptions: clonidine is an adrenergic agonist at the α2 receptor; since this receptor is located presynaptically, agonism at this receptor inhibits the presynaptic release of ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rostral Ventrolateral Medulla
The rostral ventrolateral medulla (RVLM), also known as the pressor area of the medulla, is a brain region that is responsible for basal and reflex control of sympathetic activity associated with cardiovascular function. Abnormally elevated sympathetic activity in the RVLM is associated with various cardiovascular diseases, such as heart failure and hypertension. The RVLM is notably involved in the baroreflex. It receives inhibitory GABAergic input from the caudal ventrolateral medulla (CVLM). The RVLM is a primary regulator of the sympathetic nervous system; it sends catecholaminergic projections to the sympathetic preganglionic neurons in the intermediolateral nucleus of the spinal cord via reticulospinal tract. Physostigmine, a choline-esterase inhibitor, elevates endogenous levels of acetylcholine and causes a rise in blood pressure by stimulation of the RVLM. Orexinergic neurons from the lateral hypothalamus output in the RVLM. See also * Vasomotor center The vasomot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vagus Nerve
The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and right vagus nerves—but they are typically referred to collectively as a single subsystem. The vagus is the longest nerve of the autonomic nervous system in the human body and comprises both sensory and motor fibers. The sensory fibers originate from neurons of the nodose ganglion, whereas the motor fibers come from neurons of the dorsal motor nucleus of the vagus and the nucleus ambiguus. The vagus was also historically called the pneumogastric nerve. Structure Upon leaving the medulla oblongata between the olive and the inferior cerebellar peduncle, the vagus nerve extends through the jugular foramen, then passes into the carotid sheath between the internal carotid artery and the internal jugular vein down to the neck, chest, and abdom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vasodilation
Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, which is the narrowing of blood vessels. When blood vessels dilate, the flow of blood is increased due to a decrease in vascular resistance and increase in cardiac output. Therefore, dilation of arterial blood vessels (mainly the arterioles) decreases blood pressure. The response may be intrinsic (due to local processes in the surrounding tissue) or extrinsic (due to hormones or the nervous system). In addition, the response may be localized to a specific organ (depending on the metabolic needs of a particular tissue, as during strenuous exercise), or it may be systemic (seen throughout the entire systemic circulation). Endogenous substances and drugs that cause vasodilation are termed vasodilators. Such vasoactivity is necessary for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
