SLC9A4 in the organum vasculosum of the lamina terminalis is a [Na+] sensor for the control of water intake.

SLC9A4 in the organum vasculosum of the lamina terminalis is a [Na+] sensor for the control of water intake. Pflugers Arch. 2020 May 06;: Authors: Sakuta H, Lin CH, Hiyama TY, Matsuda T, Yamaguchi K, Shigenobu S, Kobayashi K, Noda M Abstract Nax is a brain [Na+] sensor expressed in the subfornical organ (SFO) and organum vasculosum of the lamina terminalis (OVLT) in the brain. We previously demonstrated that Nax signals are involved in the control of water intake behavior through the Nax/TRPV4 pathway. Nax gene knockout mice showed significantly attenuated water intake after an intracerebroventricular (ICV) injection of a hypertonic NaCl solution; however, the induction of a certain amount of water intake still remained, suggesting that another unknown [Na+]-dependent pathway besides the Nax/TRPV4 pathway contributes to water intake. In the present study, we screened for novel [Na+] sensors involved in water intake control and identified SLC9A4 (also called sodium (Na+)/hydrogen (H+) exchanger 4 (NHE4)). SLC9A4 is expressed in angiotensin II (Ang II) receptor type 1a (AT1a)-positive neurons in the OVLT. Sodium-imaging experiments using cultured cells transfected with slc9a4 revealed that SLC9A4 was activated by increases in extracellular [Na+] ([Na+]o), but not osmolality. Moreover, the firing activity of SLC9A4-positive neurons was enhanced by increases in [Na+]o and Ang II. slc9a4 knockdown in the OVLT reduced water intake induced ...
Source: Pflugers Archiv : European Journal of Physiology - Category: Physiology Authors: Tags: Pflugers Arch Source Type: research