NO前体和供体对大鼠海马脑片神经元活动的影响

应用细胞记录单位放电技术，在大鼠海马脑片上观察了左旋精氨酸，Ｎ－硝在左旋精氨酸，ＳＩＮ－１，及亚甲基蓝对ＣＡ１区神经元自发放电的影响，旨在了解左旋精氨酸；ＮＯ通路在海马放电中的作用及其可能的机制。实验结果如下：１．用Ｌ－ａｒｇ（１ｍｍｏｌ／Ｌ）灌流海马脑片２ｍｉｎ，在５４个放电单位中有４２个单位放电频率降低，１２个单位无明显反应。

EFFECTS OF NO PRECURSOR AND DONOR ON NEURONAL ACTIVITY OF RAT HIPPOCAMPAL SLICES

Using extracellular recording technique, the effects of L-arginine (L-arg), N-ni-tro-L-arginine (L-NNA), SIN-1 and methylene blue (MB) on spontaneous dischargesof neurons in CA1 area of hippocampal slices were examined to determine the role of Larg: NO pathway and the possible underlying mechanism. The results were as follows:(1) In response to the application of L-arg (1 mmol/L) into the superfusate for 2 min,spontaneous discharge rate (SDR ) of 42/54 (77. 8 % ) neurons was decreased significantly, while that of 12/54 (22. 2 % ) neurons showed no change. Following the application of L-NNA (0. 15 mmol/L) into the superfusate for 2 min, SDR of 25/ 29(86. 2 % ) neurons was increased markedly and that of 4/29 (13. 8 % ) neurons wasn0t affected. The effect of L-NNA might be reversed by pretreatment with L-arg.(2) With application of NO donor SIN-1 (5 mmol/L), SDR of 25 (100% ) neuronswas decreased in a dose-dependent manner. (3) After superfusing the brain slice withguanylate cyc1ase inhibitor, MB (3 Umol/L) for 30 min, SDR of 10 units showed significant increase as compared with control, However, MB failed to abolish the effect ofL-arg on hippocampal neurons. Taken together, it is likely that NO is released duringthe resting state of hippocampal neurons and may inhibit the activity of hippocampus,an effect not mediated by the action of guanylate cyclase.