Takeshi Y. Hiyama

Learn More
Sodium (Na) homeostasis is crucial for life, and Na levels in body fluids are constantly monitored in the brain. The subfornical organ (SFO) is the center of the sensing responsible for the control of salt-intake behavior, where Na(x) channels are expressed in specific glial cells as the Na-level sensor. Here, we show direct interaction between Na(x)(More)
Dehydration causes an increase in the sodium (Na) concentration and osmolarity of body fluid. For Na homeostasis of the body, controls of Na and water intake and excretion are of prime importance. However, the system for sensing the Na level within the brain that is responsible for the control of Na- and water-intake behavior remains to be elucidated. We(More)
Na(x) is an atypical sodium channel that is assumed to be a descendant of the voltage-gated sodium channel family. Our recent studies on the Na(x)-gene-targeting mouse revealed that Na(x) channel is localized to the circumventricular organs (CVOs), the central loci for the salt and water homeostasis in mammals, where the Na(x) channel serves as a(More)
Body fluid conditions are continuously monitored in the brain to regulate thirst and salt-appetite sensations. Angiotensin II drives both thirst and salt appetite; however, the neural mechanisms underlying selective water- and/or salt-intake behaviors remain unknown. Using optogenetics, we show that thirst and salt appetite are driven by distinct groups of(More)
In animals, body-fluid osmolality is continuously monitored to keep it within a narrow range around a set point (∼300 mOsm/kg). Transient receptor potential vanilloid 1 (TRPV1), a cation channel, has been implicated in body-fluid homeostasis in vivo based on studies with the TRPV1-knockout mouse. However, the response of TRPV1 to hypertonic stimuli has not(More)
Na(x) is an extracellular sodium-level-sensitive sodium channel expressed in the circumventricular organs in the brain, essential loci for the sodium-level homeostasis in body fluids. Here, we examined the localization of Na(x) throughout the visceral organs at the cellular level. In visceral organs including lung, heart, intestine, bladder, kidney and(More)
Na(x) is the sodium-level sensor of body fluids in the brain involved in sodium homeostasis. Na(x)-knockout mice do not stop ingesting salt even when dehydrated. Here we report a case with clinical features of essential hypernatremia without demonstrable hypothalamic structural lesions, who was diagnosed as a paraneoplastic neurologic disorder. The patient(More)
Eiji Watanabe, Takeshi Y. Hiyama, Hidetada Shimizu, Ryuji Kodama, Noriko Hayashi, Seiji Miyata, Yuchio Yanagawa, Kunihiko Obata, and Masaharu Noda Laboratory of Neurophysiology, Division of Molecular Neurobiology, and Laboratory of Morphodiversity, National Institute for Basic Biology, Okazaki, Aichi; School of Life Science, The Graduate University for(More)