Chinese J Physiol
-
Using an in vitro primary cell culture model in which cortical neurons undergo a gradual and delayed neuronal death after a brief (5 min) challenge with glutamate receptor agonist N-methyl-D-aspartate (NMDA, 300 microM), the neuroprotective effects of various nitric oxide synthases (NOS) inhibitors were compared with that of the NMDA receptor antagonist dizocilpine maleate (MK-801). Our rat cortical cultures consisted of approximately 80-96% neurons and 5-20% astroglia as determined by immunocytochemical staining with antibodies against glial fibrillary acidic protein (GFAP) or neuron specific enolase (NSE). The delayed type of NMDA-induced neurotoxicity was examined by the morphological estimate of cell injury and was further confirmed by the activity of lactate dehydrogenase (LDH) in the extracellular fluid measured 24 hrs after the 5-min NMDA exposure. ⋯ Thus the results indicate that a brief NMDA exposure leads to delayed neuronal damage with concomitant increase in NO production in cortical neuronal cultures. We suggest that the NO may originate primarily from nNOS. The neuroprotective effects of NOS inhibitors are weaker than that of MK-801.