Nav2/NaG channel is involved in control of salt-intake behavior in the CNS.
Na(v)2/NaG is a putative sodium channel, whose physiological role has long been an enigma. We generated Na(v)2 gene-deficient mice by inserting the lacZ gene. Analysis of the targeted mice allowed us to identify Na(v)2-producing cells by examining the lacZ expression. Besides in the lung, heart, dorsal root ganglia, and Schwann cells in the peripheral nervous system, Na(v)2 was expressed in neurons and ependymal cells in restricted areas of the CNS, particularly in the circumventricular organs, which are involved in body-fluid homeostasis. Under water-depleted conditions, c-fos expression was markedly elevated in neurons in the subfornical organ and organum vasculosum laminae terminalis compared with wild-type animals, suggesting a hyperactive state in the Na(v)2-null mice. Moreover, the null mutants showed abnormal intakes of hypertonic saline under both water- and salt-depleted conditions. These findings suggest that the Na(v)2 channel plays an important role in the central sensing of body-fluid sodium level and regulation of salt intake behavior.
Watanabe
E
E
Division of Molecular Neurobiology, and Center for Transgenic Animals and Plants, National Institute for Basic Biology, Myodaiji-cho, Okazaki 444-8585, Japan.
Fujikawa
A
A
Matsunaga
H
H
Yasoshima
Y
Y
Sako
N
N
Yamamoto
T
T
Saegusa
C
C
Noda
M
M
D000284:Administration, Oral; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D002490:Central Nervous System / Q000196:embryology / Q000378:metabolism*; D004232:Diuretics / Q000494:pharmacology; D004326:Drinking / Q000502:physiology; D018390:Gene Targeting; D017930:Genes, Reporter; D006579:Heterozygote; D006720:Homozygote; D007763:Lac Operon; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D009928:Organ Specificity; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015222:Sodium Channels / Q000235:genetics / Q000502:physiology*; D017673:Sodium Chloride, Dietary / Q000378:metabolism*; D013449:Sulfonamides; D013649:Taste / Q000235:genetics; D013894:Thirst / Q000502:physiology; D061566:Voltage-Gated Sodium Channels
D004232:Diuretics; D016760:Proto-Oncogene Proteins c-fos; D011993:Recombinant Fusion Proteins; D012462:Saline Solution, Hypertonic; C503483:Scn7a protein, mouse; D015222:Sodium Channels; D017673:Sodium Chloride, Dietary; D013449:Sulfonamides; D061566:Voltage-Gated Sodium Channels