Kendrick K M, Guevara-Guzman R, de la Riva C, Christensen J, Ostergaard K, Emson P C
Department of Neurobiology, Babraham Institute, Cambridge, UK.
Eur J Neurosci. 1996 Dec;8(12):2619-34. doi: 10.1111/j.1460-9568.1996.tb01557.x.
The effects of N-methyl-D-aspartate (NMDA), kainate, S-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and KCl on striatal nitric oxide (NO), acetylcholine (ACh), dopamine (DA), serotonin (5-HT), aspartate (ASP), glutamate (GLU) and gamma-aminobutyric acid (GABA) release were measured in anaesthetized rats in vivo by microdialysis and in vitro in organotypic slice cultures. Local NMDA (1-100 microM) infusion by retrodialysis dose-dependently increased levels of classical transmitters, NO2-, NO3-, citrulline and arginine at similar thresholds (10 microM). Similar patterns of NMDA-evoked (50 microM) release were seen in striatal cultures. NMDA-evoked changes were all calcium-dependent and blocked by NMDA (APV or MK-801) but not AMPA/kainate (DNQX) receptor antagonists, excepting DA which could be prevented by both. In vivo, kainate increased NO2-, NO3-, CIT and ARG levels at 50 and 100 microM but was less potent than NMDA. Kainate also evoked significant ACh, DA and GLU release dose-dependently starting at 1-10 microM whereas 5-HT, ASP and GABA required 50 or 100 microM doses. Kainate effects were inhibited by DNQX, but not by APV, and were calcium-dependent, AMPA failed to alter NO2-, NO3-, CIT or ARG levels at 50 or 100 microM doses but dose-dependently increased ACh and DA. Similar results were seen with kainate (50 microM) and AMPA (50 microM) in vitro. KCl evoked NO2-, NO3-, CIT and ARG release as well as that of the classical transmitters in vivo and in vitro. In vivo administration of the NO synthase inhibitor L-nitroarginine (L-NARG; 100 microM) significantly reduced NO2-, NO3- and CIT levels and prevented NMDA, kainate or KCl-evoked increases. It also potentiated ACh, ASP, GLU and GABA release and reduced that of DA in response to 50 microM NMDA whereas treatment with an NO-donor (SNAP; 10 microM) significantly reduced evoked ACh, ASP and GLU release. The NO synthase inhibitor L-NARG potentiated kainate-evoked ACh release and reduced that of DA, although less potently than NMDA, but it had no effect on KCl-evoked transmitter release. Overall, these results show that both NMDA and kainate increase striatal NO release at similar dose-thresholds as for classical transmitter release suggesting that NO is dynamically released under physiological and not just pathological conditions. Reductions of striatal NO levels also potentiates calcium-dependent transmitter release in response to NMDA and, to a lesser extent, kainate, whereas increasing them reduces it. This is consistent with a role for NO as a neuroprotective agent in this region acting to desensitize NMDA receptors.
通过微透析在体内对麻醉大鼠进行测量，并在体外对器官型脑片培养物进行测量，以研究N-甲基-D-天冬氨酸（NMDA）、海人酸、S-α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）和氯化钾对纹状体一氧化氮（NO）、乙酰胆碱（ACh）、多巴胺（DA）、5-羟色胺（5-HT）、天冬氨酸（ASP）、谷氨酸（GLU）和γ-氨基丁酸（GABA）释放的影响。通过逆向透析局部注入NMDA（1 - 100微摩尔），以相似的阈值（10微摩尔）剂量依赖性地增加经典递质、NO2-、NO3-、瓜氨酸和精氨酸的水平。在纹状体培养物中也观察到类似的NMDA诱发（50微摩尔）释放模式。NMDA诱发的变化均依赖于钙，并被NMDA（APV或MK - 801）受体拮抗剂阻断，但不被AMPA/海人酸（DNQX）受体拮抗剂阻断，不过DA的释放可被两者都阻断。在体内，海人酸在50和100微摩尔时增加NO2-、NO3-、CIT和ARG水平，但效力低于NMDA。海人酸还从1 - 10微摩尔开始剂量依赖性地诱发显著的ACh、DA和GLU释放，而5-HT、ASP和GABA则需要50或100微摩尔剂量。海人酸的作用被DNQX抑制，但不被APV抑制，且依赖于钙。AMPA在50或100微摩尔剂量时未能改变NO2-、NO3-、CIT或ARG水平，但剂量依赖性地增加ACh和DA。在体外，海人酸（50微摩尔）和AMPA（50微摩尔）也得到了类似结果。氯化钾在体内和体外均诱发NO2-、NO3-、CIT和ARG释放以及经典递质的释放。在体内给予一氧化氮合酶抑制剂L-硝基精氨酸（L-NARG；100微摩尔）可显著降低NO2-、NO3-和CIT水平，并阻止NMDA、海人酸或氯化钾诱发的增加。它还增强了对50微摩尔NMDA反应时ACh、ASP、GLU和GABA的释放，并减少了DA的释放，而用一氧化氮供体（SNAP；10微摩尔）处理则显著减少诱发的ACh、ASP和GLU释放。一氧化氮合酶抑制剂L-NARG增强了海人酸诱发的ACh释放并减少了DA的释放，尽管效力低于NMDA，但对氯化钾诱发的递质释放没有影响。总体而言，这些结果表明，NMDA和海人酸增加纹状体NO释放的剂量阈值与经典递质释放相似，这表明NO在生理而非仅病理条件下动态释放。纹状体NO水平的降低也增强了对NMDA以及在较小程度上对海人酸反应时依赖于钙的递质释放，而增加NO水平则减少这种释放。这与NO作为该区域神经保护剂的作用一致，其作用是使NMDA受体脱敏。
