[Na + ] Increases in Body Fluids Sensed by Central Na x Induce Sympathetically Mediated Blood Pressure Elevations via H + -Dependent Activation of ASIC1a.

Increases in sodium concentrations ([Na ⁺ ]) in body fluids elevate blood pressure (BP) by enhancing sympathetic nerve activity (SNA). However, the mechanisms by which information on increased [Na ⁺ ] is translated to SNA have not yet been elucidated. We herein reveal that sympathetic activation leading to BP increases is not induced by mandatory high salt intakes or the intraperitoneal/intracerebroventricular infusions of hypertonic NaCl solutions in Na _x -knockout mice in contrast to wild-type mice. We identify Na _x channels expressed in specific glial cells in the organum vasculosum lamina terminalis (OVLT) as the sensors detecting increases in [Na ⁺ ] in body fluids and show that OVLT neurons projecting to the paraventricular nucleus (PVN) are activated via acid-sensing ion channel 1a (ASIC1a) by H ⁺ ions exported from Na _x -positive glial cells. The present results provide an insight into the neurogenic mechanisms responsible for salt-induced BP elevations.
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