Role of Central and Peripheral Chemoreceptors in Vasopressin Secretion Control
In this review, we analyzed the role played by central and peripheral chemoreceptors (CHRs) in vasopressin (AVP) secretion control. Central neural pathways subserving osmotic and non-osmotic control of AVP secretion are strictly correlated to brain areas participating in chemoreception mechanisms. Among the different brain areas involved in central chemoreception, the most important site has been localized in the retrotrapezoid nucleus of the rostral ventrolateral medulla. These central CHRs are able to detect very small pH/CO2 fluctuations, participating in brain blood flow regulation, acid-base balance and blood pressure control. Decreases in arterial pH and increases in arterial pCO2 stimulate AVP release by the Supraoptic and Paraventricular Nuclei. Carotid CHRs transduce low arterial O2 tension into increased action potential activity, leading to bradycardia and coronary vasodilatation via vagal stimulation, and systemic vasoconstriction via catecholaminergic stimulation. Stimulation of carotid CHRs by hypoxia increases neurohypophyseal blood flow and AVP release, an effect inhibited by CHRs denervation. Two renal CHRs have been identified: Type R1 CHRs do not have a resting discharge but are activated by renal ischemia and hypotension; Type R2 CHRs have a resting discharge and respond to backflow of urine into the renal pelvis. Signals arising from renal CHRs modulate the activity of hypothalamic AVPergic neurons: activation of R1 and R2 CHRs, following increased intrapelvic pressure with solutions of mannitol, NaCl and KCl, produces a significant increase of AVP secretion and the same effect has been obtained by the intrarenal infusion of bradykinin, which excites afferent renal nerves, as well as by the electrical stimulation of these nerves.
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Document Type: Research Article
Publication date: September 1, 2013
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- This journal is devoted to timely reviews of experimental and clinical studies in the field of endocrine, metabolic, and immune disorders. Specific emphasis is placed on humoral and cellular targets for natural, synthetic, and genetically engineered drugs that enhance or impair endocrine, metabolic, and immune parameters and functions. Topics related to the neuroendocrine-immune axis are given special emphasis in view of the growing interest in stress-related, inflammatory, autoimmune, and degenerative disorders.
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