Arcuate nucleus – Wikipedia

The arcuate nucleus of the hypothalamus (also known as ARH,[1] ARC,[2] or infundibular nucleus[2][3]) is an aggregation of neurons in the mediobasal hypothalamus, adjacent to the third ventricle and the median eminence. The arcuate nucleus includes several important and diverse populations of neurons that help mediate different neuroendocrine and physiological functions, including: neuroendocrine neurons, centrally projecting neurons, and astrocytes. The populations of neurons found in the arcuate nucleus are based on the hormones they secrete or interact with and are responsible for hypothalamic function, such as regulating hormones released from the pituitary gland or secreting their own hormones. Neurons in this region are also responsible for integrating information and providing inputs to other nuclei in the hypothalamus or inputs to areas outside this region of the brain. These neurons, generated from the ventral part of the periventricular epithelium during embryonic development, locate dorsally in the hypothalamus, becoming part of the ventromedial hypothalamic region.[1][2][4] The function of the arcuate nucleus relies on its diversity of neurons, but its central role is involved in homeostasis. The arcuate nucleus provides many physiological roles involved in feeding, metabolism, fertility, and cardiovascular regulation.[1][2][4][5]

Different groups of arcuate nucleus neuroendocrine neurons secrete various types or combinations of neurotransmitters and neuropeptides, such as neuropeptide Y (NPY), gonadotropin-releasing hormone (GnRH), agouti-related peptide (AgRP), cocaine- and amphetamine-regulated transcript (CART), kisspeptin, dopamine, substance P, growth hormonereleasing hormone (GHRH), neurokinin B (NKB), -endorphin, melanocyte-stimulating hormone (MSH), and somatostatin. Proopiomelanocortin (POMC) is a precursor polypeptide that is cleaved into MSH and -endorphin and expressed in the arcuate nucleus.[1]

Groups of neuroendocrine neurons include:

Other types of neurons have projection pathways from the arcuate nucleus to mediate different regions of the hypothalamus or to other regions outside of the hypothalamus.[2][4] Projections of these neurons extend a long distance from the arcuate nucleus to the median eminence to influence the release of hormones from the pituitary gland.[1][2] Neurons of the arcuate nucleus have intrahypothalamic projections for neuroendrocrine circuitry.[1] such as neural projections that influence feeding behavior project to the paraventricular nucleus of the hypothalamus (PVH), the dorsomedial hypothalamic nucleus (DMH, and the lateral hypothalamic area (LHA).[1] Populations of neurons connect to the intermediate lobes of the pituitary gland, from the lateral division of the ARH to the neural and intermediate parts of the pituitary gland, and the caudal division of ARH to the median eminence.[2]

Groups of neurons that project elsewhere within the central nervous system include:

Other cell populations include:

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Arcuate nucleus - Wikipedia