Developmental Differences in NMDA Neurototoxicity and the Expression of NMDA Receptor 2B Subunit of Rat Hippocampus

J Korean Neurol Assoc > Volume 25(3); 2007 > Article

Journal of the Korean Neurological Association 2007;25(3): 364-371.

쥐 해마의 발달과정에서 N-methyl-D-aspartate 신경독성과 N-methyl-D-aspartate 수용체 2B 서브유닛의 발현양상

윤영철, 박태환 권오상 채수안a 이정수b

중앙대학교 의과대학 신경과학교실, 소아과학교실a, 약리학교실b

Developmental Differences in NMDA Neurototoxicity and the Expression of NMDA Receptor 2B Subunit of Rat Hippocampus

Young Chul Youn

Department of Neurology, Pediatricsa and Pharmacologyb, College of Medicine, Chung-Ang University, Seoul, Korea

Abstract

Background: The developing brain has a distinctive set of characteristics that make it have different susceptibility to excitotoxins. Using primary tissue cultures of rat hippocampus, we investigated the developmental susceptibility to N-methyl-D-aspartic acid (NMDA)-induced cell death at various days in vitro in relation to the appearance of Bcl-2 protein and NMDA receptor 2B subunit.
Methods: Six, 12, and 18 days-in-vitro (DIV) hippocampal tissue cultures derived from 7-day-old Sprague-Dawley rat pups were used. Each group was treated with 100 μM NMDA in 5% CO2 incubator at 36℃ for 30 min. A western blot was then performed for the NeuN, Bcl-2 and NMDA receptor 2B subunit and propidium Iodide (PI) staining.
Results: The NeuN and Bcl-2 were most highly expressed in 12 DIV tissues. The reductions of the NeuN and Bcl-2 protein expressions by NMDA were significant at the 12 and the 18 DIV tissues, but less at 6 DIV tissues (p<0.05). The PI staining showed that the area of fluorescence of the 7 DIV tissues after NMDA exposure was less than the DIV 13 and 19 tissues. Without NMDA treatment, the NMDA receptor 2B subunit protein expressions at the 6 DIV tissues were highest and decreased with maturation.
Conclusions: These results suggest that the immature tissues were more resistant to NMDA toxicity than the mature tissues, and further studies are needed to establish its relationship with the Bcl-2 protein and NMDA receptor 2B subunit. KeyWords:Hippocampus, Bcl2, NeuN protein, N-methyl-D-aspartate, NR2B protein