Vasopressin: Structure, Biosynthesis, Mechanism of Action, and Uses, Slides of Medicine

Download Vasopressin: Structure, Biosynthesis, Mechanism of Action, and Uses and more Slides Medicine in PDF only on Docsity! VASOPRESSIN STRUCTURE •Vasopressin is a cyclic nonapeptide with a disulfide bridge between residues cysteine(Cys1) and (Cys6), and a tail comprising residues seven to nine. BIOSYNTHESIS •synthesized in overlapping regions of the hypothalamus, primarily in large magnocellular neurons situated in the supraoptic and paraventricular nuclei. •These neurons project their axons to the posterior pituitary, where the peptides are stored in vesicles until action potentials trigger their release into the peripheral circulation (for example during imbalance of water homeostasis) . CONTINUE........ Secretion to Brain Sites from Parwocellular NMeurons C(rwellow) Parawemtricular Mucthei Dendritic Secretia, Meurons (G heel Optic Chiasm ANxXxoOnic Secretion — from Magnocellular Meurons to Peripherial Circulation Supracptic Muclei Anterior Pituitary Posterior Pituitary FACTORS THAT TRIGGER VASOPRESSIN FROM PITUATARY •Hypovolumia •Hypotension •Hypothalamic osmoreceptor •Angiotensin ll • Hypovolemia, as occurs during hemorrhage and dehydration, results in a decrease in atrial pressure. Atrial receptor firing normally inhibits the release of AVP by the posterior pituitary. With hypovolemia or decreased central venous pressure, the decreased firing of atrial stretch receptors leads to an increase in AVP release. • Hypotension, which decreases arterial baroreceptor firing, leads to enhanced sympathetic activity that increases AVP release. • Hypothalamic osmoreceptors sense extracellular osmolarity and stimulate AVP release when osmolarity rises, as occurs with dehydration. • Angiotensin II receptors located in a region of the hypothalamus regulate AVP release – an increase in angiotensin II simulates AVP release. MECHANISM OF A Hyperosmotarny AMmGQtoternsin i atria receptor firing Wasopressim ww: W2> Increased Systemic increased WMVascular Resistance Biocod Volume | increased Aarterial Pressure Syrnpametic Stirnulatiom  Osmoreceptors Central nervous system Kidney: Increases tubular water resorption Vasorelaxation: Cerebral arteries Coronary arteries Vasopressin (ADH) Vasoconstriction: Cutaneous peripheral USES •Antidiuretic activity •Polyuria •In the treatment of gastrointestinal bleeding. •Ventricular tachycardia •Ventricular defibrillation. •Vasopressin is used to treat diabetes insipidus related to low levels of antidiuretic hormone REFERENCE * https:// www.frontiersin.org/articles/10.3389/fins.2015.00335/f ull#h5 ° https://academic.oup.com/bjaed/article/8/4/134/294005 * https://www.cvphysiology.com/Blood%20Pressure/BP016