Effect of hypertonic saline on rat hypothalamic paraventricular nucleus magnocellular neurons in vitro.
The effect of hypertonic saline on rat hypothalamic paraventricular nucleus (PVN) magnocellular neurons was examined using a whole-cell patch-clamp technique. Under a current-clamp, 58/68 of magnocellular neurons were depolarized by hypertonic stimulation. Under a voltage-clamp, hypertonic saline produced an inward current via increased non-selective cationic conductance and shifting of the reversal potential to more positive values. Furthermore, hypertonic saline even without a change in osmolality increased spontaneous excitatory postsynaptic currents (sEPSCs). A bath application of CNQX almost completely blocked EPSCs. Extracellular application of gadolinium blocked the hypertonic saline- and mannitol-induced response. These results suggest that PVN magnocellular neurons are responsive to osmolality and Na+ concentrations. Hypertonic saline excited PVN magnocellular neurons via osmo-reception, Na+ -detection, and excitatory glutamatergic synaptic input.
Qiu
De-Lai
DL
Department of Physiology, Miyazaki Medical College, 5200 Kihara, Kiyotake-cho, Miyazaki-gun, Miyazaki 889-1692, Japan.
Shirasaka
Tetsuro
T
Chu
Chun-Ping
CP
Watanabe
Shoichi
S
Yu
Nan-Shou
NS
Katoh
Takahiko
T
Kannan
Hiroshi
H
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000344:Afferent Pathways / Q000187:drug effects / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D045604:Extracellular Fluid / Q000187:drug effects / Q000378:metabolism; D005682:Gadolinium / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D066298:In Vitro Techniques; D008353:Mannitol / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009994:Osmolar Concentration; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology*
D018691:Excitatory Amino Acid Antagonists; D012462:Saline Solution, Hypertonic; D018698:Glutamic Acid; D008353:Mannitol; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D012964:Sodium; D005682:Gadolinium