Best practice & research. Clinical anaesthesiology
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Best Pract Res Clin Anaesthesiol · Jun 2008
ReviewPhysiology and pathophysiology of the vasopressinergic system.
Arginine vasopressin, a hypothalamic peptide hormone, has multiple physiological functions, including body water regulation, control of blood pressure and effects on body temperature, insulin release, corticotropin release, memory and social behaviour. These functions are achieved via at least three specific G-protein-coupled vasopressin receptors. ⋯ The complex signalling and messenger processes which take place after receptor stimulation are now more clearly understood. Vasopressin dysregulation can occur in various disease processes, and a better understanding of the mechanisms underlying physiological synthesis, release and regulation of vasopressin will help in the development of therapies to treat these conditions.
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Best Pract Res Clin Anaesthesiol · Jun 2008
ReviewImpact of vasopressin analogues on the gut mucosal microcirculation.
Given the controversial experimental and clinical data reported in the literature, up to now it is rather difficult to draw a definitive conclusion on the effects of V1 agonists on splanchnic haemodynamics. Nevertheless, it must be underscored that most of the experimental studies assessing the effects of low dose V1 agonist infusion in hyperdynamic models did not demonstrate any detrimental effect on splanchnic haemodynamics both at macro- and microcirculatory levels. ⋯ In clinical studies in patients with septic shock, data are accumulating regarding the absence of clinically relevant side effects in the splanchnic region when vasopressin is used, but conversely little is known about the safety of terlipressin, mainly because of the small number of patients studied. Thus, the absence of clinically harmful effect does not exclude covert splanchnic ischaemia, which may counterbalance the beneficial systemic effects.
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Best Pract Res Clin Anaesthesiol · Jun 2008
ReviewEndocrine effects of vasopressin in critically ill patients.
Vasopressin, also called antidiuretic hormone, is a 9 amino-acid peptide, synthesized from a precursor containing neurophysin II, by neurones from the supra-optic and peri-ventricular nuclei, and then stored in the posterior hypophysis. Vasopressin regulates plasmatic osmolality and volaemia via V2 receptors at the levels of the kidney, and vascular smooth muscle tone via V1a arterial receptors. ⋯ Interestingly, during critical illness, exogenous administration of vasopressin showed little effects on the circulating levels of these various hormones, except an increase in prolactin. The absence of endocrine effects of vasopressin during critical illness is unclear and may relate to an already maximal hormonal stimulation or to down-regulation of vasopressin receptors.
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This review article summarizes the structure, signalling pathways, and tissue distribution of the vasopressin receptors, V1 vascular, V2 renal, V3 pituitary, and oxytocin receptors, as well as the P2 class of purinoceptors. The physiological effects of vasopressin on its receptors are described. The future direction with regard to the role of the V1a receptor in circulatory shock states is discussed; further studies with V1a receptor agonists are warranted to further develop treatment strategies to reduce mortality in life threatening diseases like septic shock.