Nucleus, water retention

Q3 Vasopressin is a small peptide hormone consisting of nine amino acids, most of which is synthesized in neurosecretory cells of the supraoptic nucleus of the hypothalamus. Small quantities are also produced in the neighbouring paraventricular nucleus. The hormone is transported down the axons of the neurosecretory cells via the infundibulum to the posterior pituitary, where it is stored until release into the blood is triggered by nerve impulses from the hypothalamus. Vasopressin is better known as antidiuretic hormone (ADH). The name vasopressin relates to its vasoconstrictor action, which increases pressure in the vascular system. This action was discovered before its effects on water retention were known. 

Nucleus is a zone of water retention and reciystallized product (seed crystals)... 

Two AT-II receptors, AT and AT2 are known and show wide distribution (27). The AT receptor has been cloned and predominates ia regions iavolved ia the regulation of blood pressure and water and sodium retention, eg, the aorta, Hver, adrenal cortex, and ia the CNS ia the paraventricular nucleus, area postrema, and nucleus of the soHtary tract. AT2 receptors are found primarily ia the adrenal medulla, utems, and ia the brain ia the locus coeruleus and the medial geniculate nucleus. AT receptors are GCPRs inhibiting adenylate cyclase activity and stimulating phosphoHpases C, A2, and D. AT2 receptors use phosphotyrosiae phosphatase as a transduction system. 

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