Total RNA was isolated by RNAeasy kit (Qiagen) from cells or SN samples microdissected from the brain. One microgram of total RNA was used for cDNA synthesis using Superscript III (Invitrogen), and quantitative PCR was performed with SYBR-GreenER (Invitrogen) detected by 7300 Real Time PCR System (ABI). The sequences of qPCR primers used for mRNA quantification in this study were obtained from PrimerBank (Wang and Seed, 2003).
