Effect of hypertonic saline on rat hypothalamic paraventricular nucleus magnocellular neurons in vitro

De-Lai Qiu; Tetsuro Shirasaka; Chun-Ping Chu; Shoichi Watanabe; Nan-Shou Yu; Takahiko Katoh; Hiroshi Kannan

doi:10.1016/j.neulet.2003.11.002

Effect of hypertonic saline on rat hypothalamic paraventricular nucleus magnocellular neurons in vitro

Neurosci Lett. 2004 Jan 23;355(1-2):117-20. doi: 10.1016/j.neulet.2003.11.002.

Authors

De-Lai Qiu¹, Tetsuro Shirasaka, Chun-Ping Chu, Shoichi Watanabe, Nan-Shou Yu, Takahiko Katoh, Hiroshi Kannan

Affiliation

¹ Department of Physiology, Miyazaki Medical College, 5200 Kihara, Kiyotake-cho, Miyazaki-gun, Miyazaki 889-1692, Japan.

PMID: 14729249
DOI: 10.1016/j.neulet.2003.11.002

Abstract

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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
Action Potentials / drug effects
Action Potentials / physiology*
Afferent Pathways / drug effects
Afferent Pathways / physiology
Animals
Animals, Newborn
Excitatory Amino Acid Antagonists / pharmacology
Excitatory Postsynaptic Potentials / drug effects
Excitatory Postsynaptic Potentials / physiology
Extracellular Fluid / drug effects
Extracellular Fluid / metabolism
Gadolinium / pharmacology
Glutamic Acid / metabolism
In Vitro Techniques
Mannitol / pharmacology
Neurons / drug effects
Neurons / physiology*
Osmolar Concentration
Paraventricular Hypothalamic Nucleus / drug effects
Paraventricular Hypothalamic Nucleus / physiology*
Patch-Clamp Techniques
Rats
Rats, Wistar
Saline Solution, Hypertonic / pharmacology*
Sodium / metabolism
Synaptic Transmission / drug effects
Synaptic Transmission / physiology
Water-Electrolyte Balance / drug effects
Water-Electrolyte Balance / physiology*

Substances

Excitatory Amino Acid Antagonists
Saline Solution, Hypertonic
Glutamic Acid
Mannitol
6-Cyano-7-nitroquinoxaline-2,3-dione
Sodium
Gadolinium