Qiu De-Lai, Shirasaka Tetsuro, Chu Chun-Ping, Watanabe Shoichi, Yu Nan-Shou, Katoh Takahiko, Kannan Hiroshi
Department of Physiology, Miyazaki Medical College, 5200 Kihara, Kiyotake-cho, Miyazaki-gun, Miyazaki 889-1692, Japan.
Neurosci Lett. 2004 Jan 23;355(1-2):117-20. doi: 10.1016/j.neulet.2003.11.002.
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.
采用全细胞膜片钳技术研究了高渗盐水对大鼠下丘脑室旁核（PVN）大细胞神经元的影响。在电流钳模式下，68个大细胞神经元中有58个在高渗刺激下发生去极化。在电压钳模式下，高渗盐水通过增加非选择性阳离子电导和将反转电位向更正的值移动而产生内向电流。此外，即使渗透压没有变化，高渗盐水也会增加自发兴奋性突触后电流（sEPSCs）。浴槽应用CNQX几乎完全阻断了EPSCs。细胞外应用钆可阻断高渗盐水和甘露醇诱导的反应。这些结果表明，PVN大细胞神经元对渗透压和Na+浓度有反应。高渗盐水通过渗透压感受、Na+检测和兴奋性谷氨酸能突触输入来兴奋PVN大细胞神经元。
