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α2 Receptor
The alpha-2 (α2) adrenergic receptor (or adrenoceptor) is a G protein-coupled receptor (GPCR) associated with the Gi heterotrimeric G-protein. It consists of three highly homologous subtypes, including α2A-, α2B-, and α2C-adrenergic. Some species other than humans express a fourth α2D-adrenergic receptor as well. Catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) signal through the α2-adrenergic receptor in the central and peripheral nervous systems. Cellular localization The α2A adrenergic receptor is localised in the following central nervous system (CNS) structures: * Brainstem (especially the locus coeruleus as presynaptic & somatodendritic autoreceptor ) * Midbrain * Hypothalamus * Olfactory system * Hippocampus * Spinal cord * Cerebral cortex * Cerebellum * Septum Whereas the α2B adrenergic receptor is localised in the following CNS structures: * Thalamus * Pyramidal layer of the hippocampus * Cerebellar Purkinje layer and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hippocampus
The hippocampus (: hippocampi; via Latin from Ancient Greek, Greek , 'seahorse'), also hippocampus proper, is a major component of the brain of humans and many other vertebrates. In the human brain the hippocampus, the dentate gyrus, and the subiculum are components of the hippocampal formation located in the limbic system. The hippocampus plays important roles in the Memory consolidation, consolidation of information from short-term memory to long-term memory, and in spatial memory that enables Navigation#Navigation in spatial cognition, navigation. In humans, and other primates the hippocampus is located in the archicortex, one of the three regions of allocortex, in each cerebral hemisphere, hemisphere with direct neural projections to, and reciprocal indirect projections from the neocortex. The hippocampus, as the medial pallium, is a structure found in all vertebrates. In Alzheimer's disease (and other forms of dementia), the hippocampus is one of the first regions of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympathetic Nervous System
The sympathetic nervous system (SNS or SANS, sympathetic autonomic nervous system, to differentiate it from the somatic nervous system) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of the autonomic nervous system, and sometimes considered an independent system. The autonomic nervous system functions to regulate the body's unconscious actions. The sympathetic nervous system's primary process is to stimulate the body's fight or flight response. It is, however, constantly active at a basic level to maintain homeostasis. The sympathetic nervous system is described as being antagonistic to the parasympathetic nervous system. The latter stimulates the body to "feed and breed" and to (then) "rest-and-digest". The SNS has a major role in various physiological processes such as blood glucose levels, body temperature, cardiac output, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vascular Smooth Muscle
Vascular smooth muscle is the type of smooth muscle that makes up most of the walls of blood vessels. Structure Vascular smooth muscle refers to the particular type of smooth muscle found within, and composing the majority of the wall of blood vessels. Nerve supply Vascular smooth muscle is innervated primarily by the sympathetic nervous system through adrenergic receptors (adrenoceptors). The three types present are: alpha-1, alpha-2 and beta-2 adrenergic receptors, . The main endogenous agonist of these cell receptors is norepinephrine (NE). The adrenergic receptors exert opposite physiologic effects in the vascular smooth muscle under activation: * alpha-1 receptors. Under NE binding alpha-1 receptors cause vasoconstriction (contraction of the vascular smooth muscle cells decreasing the diameter of the vessels). These receptors are activated in response to shock or low blood pressure as a defensive reaction trying to restore the normal blood pressure. Antagonists o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventral Tegmentum
The 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. The VTA plays an important role in a number of processes, including reward cognition (motivational salience, associative learning, and positively-valenced emotions) and orgasm, among others, as well as several psychiatric disorders. Neurons in the VTA project to numerous areas of the brain, ranging from the prefrontal cortex to the caudal brainstem and several regions in between. Structure Neurobiologists have often had great difficulty distinguishing the VTA in humans and other primate brains from the substantia nigra (SN) and surrounding nuclei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substantia Nigra
The substantia nigra (SN) is a basal ganglia structure located in the midbrain that plays an important role in reward and movement. ''Substantia nigra'' is Latin for "black substance", reflecting the fact that parts of the substantia nigra appear darker than neighboring areas due to high levels of neuromelanin in dopaminergic neurons. Parkinson's disease is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta. Although the substantia nigra appears as a continuous band in brain sections, anatomical studies have found that it actually consists of two parts with very different connections and functions: the pars compacta (SNpc) and the pars reticulata (SNpr). The pars compacta serves mainly as a projection to the basal ganglia circuit, supplying the striatum with dopamine. The pars reticulata conveys signals from the basal ganglia to numerous other brain structures. Structure The substantia nigra, along with four other nuclei, is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal Ganglia
The basal ganglia (BG) or basal nuclei are a group of subcortical Nucleus (neuroanatomy), nuclei found in the brains of vertebrates. In humans and other primates, differences exist, primarily in the division of the globus pallidus into external and internal regions, and in the division of the striatum. Positioned at the base of the forebrain and the top of the midbrain, they have strong connections with the cerebral cortex, thalamus, brainstem and other brain areas. The basal ganglia are associated with a variety of functions, including regulating voluntary motor control, motor movements, procedural memory, procedural learning, habituation, habit formation, conditional learning, eye movements, cognition, and emotion. The main functional components of the basal ganglia include the striatum, consisting of both the dorsal striatum (caudate nucleus and putamen) and the ventral striatum (nucleus accumbens and olfactory tubercle), the globus pallidus, the ventral pallidum, the substa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Root Ganglia
A dorsal root ganglion (or spinal ganglion; also known as a posterior root ganglion) is a cluster of neurons (a ganglion) in a dorsal root of a spinal nerve. The cell bodies of sensory neurons known as first-order neurons are located in the dorsal root ganglia. The axons of dorsal root ganglion neurons are known as afferents. In the peripheral nervous system, afferents refer to the axons that relay sensory information into the central nervous system (i.e. the brain and the spinal cord). Structure The neurons comprising the dorsal root ganglion are of the pseudo-unipolar type, meaning they have a cell body (soma) with two branches that act as a single axon, often referred to as a ''distal process'' and a ''proximal process''. Unlike the majority of neurons found in the central nervous system, an action potential in posterior root ganglion neuron may initiate in the ''distal process'' in the periphery, bypass the cell body, and continue to propagate along the ''proximal proces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amygdala
The amygdala (; : amygdalae or amygdalas; also '; Latin from Greek language, Greek, , ', 'almond', 'tonsil') is a paired nucleus (neuroanatomy), nuclear complex present in the Cerebral hemisphere, cerebral hemispheres of vertebrates. It is considered part of the limbic system. In Primate, primates, it is located lateral and medial, medially within the temporal lobes. It consists of many nuclei, each made up of further subnuclei. The subdivision most commonly made is into the Basolateral amygdala, basolateral, Central nucleus of the amygdala, central, cortical, and medial nuclei together with the intercalated cells of the amygdala, intercalated cell clusters. The amygdala has a primary role in the processing of memory, decision making, decision-making, and emotions, emotional responses (including fear, anxiety, and aggression). The amygdala was first identified and named by Karl Friedrich Burdach in 1822. Structure Thirteen Nucleus (neuroanatomy), nuclei have been identif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha-2C Adrenergic Receptor
The alpha-2C adrenergic receptor (α2C adrenoceptor), also known as ADRA2C, is an alpha-2 adrenergic receptor, and also denotes the human gene encoding it. Receptor Alpha-2-adrenergic receptors include 3 highly homologous subtypes: alpha2A, alpha2B, and alpha2C. These receptors have a critical role in regulating neurotransmitter release from sympathetic nerves and from adrenergic neurons in the central nervous system. Studies in mice revealed that both the alpha2A and alpha2C subtypes were required for normal presynaptic control of transmitter release from sympathetic nerves in the heart and from central noradrenergic neurons; the alpha2A subtype inhibited transmitter release at high stimulation frequencies, whereas the alpha2C subtype modulated neurotransmission at lower levels of nerve activity. Gene This gene encodes the alpha2C subtype, which contains no introns in either its coding or untranslated sequences. Ligands Agonists * (R)-3-Nitrobiphenyline (also we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha-2B Adrenergic Receptor
The alpha-2B adrenergic receptor (α2B adrenoceptor), is a G-protein coupled receptor. It is a subtype of the adrenergic receptor family. The human gene encoding this receptor has the symbol ADRA2B. ADRA2B orthologs have been identified in several mammals. Receptor α2-adrenergic receptors include 3 highly homologous subtypes: α2A, α2B, and α2C. These receptors have a critical role in regulating neurotransmitter release from sympathetic nerves and from adrenergic neurons in the central nervous system. Clinical significance This gene encodes the α2B subtype, which was observed to associate with eIF-2B, a guanine nucleotide exchange protein that functions in regulation of translation. A polymorphic variant of the α2B subtype, which lacks 3 glutamic acids from a glutamic acid repeat element, was identified to have decreased G protein-coupled receptor kinase-mediated phosphorylation and desensitization; this polymorphic form is also associated with reduced basal metabo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Septum
In biology, a septum (Latin language, Latin for ''something that encloses''; septa) is a wall, dividing a Body cavity, cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatrial septum, the wall of tissue that is a sectional part of the left and right atria of the heart * Interventricular septum, the wall separating the left and right ventricles of the heart * Lingual septum, a vertical layer of fibrous tissue that separates the halves of the tongue *Nasal septum: the cartilage wall separating the nostrils of the nose * Alveolar septum: the thin wall which separates the Pulmonary alveolus, alveoli from each other in the lungs * Orbital septum, a palpebral ligament in the upper and lower eyelids * Septum pellucidum or septum lucidum, a thin structure separating two fluid pockets in the brain * Uterine septum, a malformation of the uterus * Septum of the penis, Penile septum, a fibrous w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
