The serine racemase mRNA is predominantly expressed in rat brain neurons.
D-serine is an endogenous and obligatory coagonist for the glycine site of the N-methyl-D-aspartate receptor in the mammalian brain. D-serine is synthesized from L-serine by serine racemase; immunohistochemical studies have long been believed to indicate that serine racemase and D-serine occur predominantly in astrocytes. However, we have recently demonstrated in the primary cultures that both the mRNA and protein levels of serine racemase are higher in neurons than in astrocytes. Here we report the application of in situ hybridization based on tyramide signal amplification for the detection of serine racemase mRNA in sections of the adult rat brain. Serine racemase mRNA could be demonstrated in a large number of neurons throughout the brain, especially in the forebrain such as the cerebral cortex, striatum, and hippocampus. This is the first study to demonstrate the exact localization of serine racemase mRNA at the cellular or tissue level. These results suggest that neuron-derived D-serine could modulate neurotransmission via the glycine site of N-methyl-D-aspartate receptors.
Yoshikawa
Masanobu
M
Department of Clinical Pharmacology, Laboratory for Molecular Science Research, Tokai University School of Medicine, Isehara, Kanagawa, Japan.
Takayasu
Naoko
N
Hashimoto
Atsushi
A
Sato
Yuichi
Y
Tamaki
Raita
R
Tsukamoto
Hideo
H
Kobayashi
Hiroyuki
H
Noda
Setsuko
S
D000818:Animals; D015152:Blotting, Northern; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D009474:Neurons / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis*; D019998:Racemases and Epimerases / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D000099300:Serine Racemase