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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] |
