Sleep deprivation inhibits expression of NADPH-d and NOS while activating microglia and astroglia in the rat hippocampus.
This study investigated the expression of nitric oxide (NO)-synthesizing enzymes and the glial reaction in the rat hippocampal formation following sleep deprivation for 5 days. Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) reactivity was markedly reduced in the hippocampal CA1, CA2 and CA3 sectors as well as in the dentate gyrus, suggesting a suppression of NO production in these areas. Microglial cells were hypertrophic and showed an up-regulation of complement type 3 receptors as determined by antibody OX-42. However, expression of major histocompatibility complex class I and II antigens, and antigen of monocyte/macrophage lineage marked by OX-18, OX-6 and ED1, respectively, was undetected. Astrocytes also displayed hypertrophied processes with enhanced glial fibrillary acidic protein (GFAP) immunoreactivity. Western blots of hippocampal tissues corroborated the above-mentioned morphological findings in that expression of NO-synthase (NOS) was decreased while that of OX-42 and GFAP was increased in the sleep-deprived rats. Since NO is thought to be involved in memory consolidation processes in the hippocampus during sleep, the inhibition of NADPH-d and NOS reactivities may account for the memory decline after long-term sleep deprivation. The concomitant reactions in microglia and astrocytes suggest the involvement of these cells in the deleterious effect of prolonged sleep deprivation.
Hsu
Jee-Ching
JC
Department of Anesthesiology, Chang-Gung Memorial Hospital, Linkou, Taiwan, ROC.
Lee
Ying-Shiung
YS
Chang
Chen-Nen
CN
Chuang
Huo-Li
HL
Ling
Eng-Ang
EA
Lan
Chyn-Tair
CT
D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D015153:Blotting, Western; D018891:Dentate Gyrus / Q000378:metabolism; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D017628:Microglia / Q000378:metabolism*; D009252:NADPH Dehydrogenase / Q000096:biosynthesis*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase; D051381:Rats; D017207:Rats, Sprague-Dawley; D012890:Sleep; D013997:Time Factors; D015854:Up-Regulation
D005904:Glial Fibrillary Acidic Protein; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D009252:NADPH Dehydrogenase