Urotensin Ⅱ inhibits electrical activity of hippocampal CA1 neurons by potentiating the GABA_A receptor-mediated Cl^- current  

作　　者：Yu-Ming WU Ru WANG Rui-Rong HE 

机构地区：[1]Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017,China

出　　处：《Neuroscience Bulletin》2006年第2期110-114,共5页神经科学通报（英文版）

摘　　要：Objective To examine the effects of urotensin Ⅱ （UⅡ） on the discharges of neurons in CA1 area of hippocampal slices by using extracellular recording technique. Results ①In response to the application of UⅡ （0.3, 3.0, 30.0,300.0 nmol/L, n = 77） into the perfusate for 2 min, the spontaneous discharge rates （SDR） of 63/77 （81.8% ） neurons were significantly decreased in a dose-dependent manner. ②Pretreatment with bicuculline（BIC, 100 μmol/L）, a specific GABAs receptor antagonist, led to a marked increase in the SDR of 6/7 （85.71%） neurons in an epileptiform pattern. The increased discharges were not significantly changed after UⅡ （30.0 nmol/L） was applied into the perfusate for 2 min. ③Pretreatment with picrotoxin （ PIC, 50 μmol/L）, a selective blocker of Cl^- channel, led to an increase in the SDR of all 8/8（ 100% ） neurons. The increased discharges were not influenced by the UⅡ （30.0 nmol/L） applied. ④Application of nitric oxide synthase （NOS） inhibitor N^G nitro-L-arginine methyl ester （L-NAME, 50μmol/L） into the perfusate for 2 min also significantly augmented the SDR of 14/16 （87.5 % ） neurons , then UⅡ （30.0 nmol/L） applied into the perfusate reduced the increased the SDR of all 14/14 （ 100% ） neurons. Conclusion These results suggest that UⅡ may decrease neuronal activity by potentiating GABAA receptor-mediated CI current in hippocampal CA1 neurons, and involved with the mediation of nitric oxide.Objective To examine the effects of urotensin Ⅱ (UII) on the discharges of neurons in CA1 area of hipp-ocampal slices by using extracellular recording technique. Results (1)In response to the application of UII (0.3 , 3.0, 30.0, 300.0 nmol/L, n=77) into the perfusate for 2 min, the spontaneous discharge rates (SDR) of 63/77 (81.8%) neurons were significantly decreased in a dose-dependent manner. (2)Pretreatment with bicuculline(BIC,100μmol/L) , a specific GABAA receptor antagonist, led to a marked increase in the SDR of 6/7 (85.71% ) neurons in an epileptiform pattern. The increased discharges were not significantly changed after UII (30.0 nmol/L) was applied into the perfusate for 2 min. (3) Pretreatment with picrotoxin (PIC, 50μmol/L) , a selective blocker of Cl- channel, led to an increase in the SDR of all 8/8(100% ) neurons. The increased discharges were not influenced by the UII (30.0 nmol/L) applied. (4)Application of nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 50μmol/L) into the perfusate for 2 min also significantly augmented the SDR of 14/16 (87.5% ) neurons , then UII (30. 0 nmol/L) applied into the perfusate reduced the increased the SDR of all 14/14 ( 100% ) neurons. Conclusion These results suggest that UII may decrease neuronal activity by potentiating GABAA receptor-mediated Cl- current in hippocampal CA1 neurons, and involved with the mediation of nitric oxide.

关 键 词：hippocampal slice urotensin Ⅱ BICUCULLINE L-NAME PICROTOXIN 

分 类 号：Q426[生物学—神经生物学] R338.4[生物学—生理学]