Vasopressorina

Vasopressorina, also known as vasopressin or antidiuretic hormone (ADH), is a peptide hormone produced in the hypothalamus and released from the posterior pituitary. It also acts as a neurotransmitter and neuromodulator in the brain. In circulation, vasopressorina helps regulate body water balance and vascular tone.

In the kidney, it binds to V2 receptors on principal cells in the collecting ducts, promoting insertion of aquaporin-2 channels into the apical membrane. This increases water reabsorption and concentrates the urine. In the vascular system, vasopressorina binds to V1 receptors on vascular smooth muscle, causing vasoconstriction and raising systemic vascular resistance. The receptor subtypes V1a, V1b (also called V3), and V2 mediate distinct physiological effects: V1a for vasoconstriction, V1b for ACTH release from the pituitary, and V2 for water reabsorption.

Synthesis and processing begin in the hypothalamus with generation of a preprovasopressin precursor, which is packaged with its carrier proteins, neurophysin II and copeptin, for transport and storage in posterior pituitary vesicles. Upon release, vasopressorina and copeptin are secreted together.

Clinical relevance includes treatment of central diabetes insipidus with vasopressin or its analogs. Desmopressin is a synthetic analog used for bleeding disorders and nocturnal enuresis. In acute care, vasopressorina has been used as a vasopressor to raise blood pressure and control variceal bleeding, often as an adjunct to other therapies. Side effects may include hyponatremia, water intoxication, and ischemic events due to excessive vasoconstriction.