The chronic inhibition of nitric oxide synthase enhances cell proliferation in the adult rat hippocampus.
We investigated the effect of chronic blocking nitric oxide synthase (NOS), an enzyme producing NO from L-arginine, on granule cell proliferation in the dentate gyrus of adult rats under normal conditions. We treated 7-nitroindazole (7-NI) for 5, 15, and 25 days or N-nitro-L-arginine-methyl ester (L-NAME) for 25 days to block NOS activity and subsequently injected 5-bromo-2-deoxyuridine (BrdU) to detect proliferating cells. The BrdU-immunoreactive (IR) cell number was significantly increased in the 7-NI 15 and 25 day treated group, but not in the control or in the 7-NI 5 day treated group. L-NAME treatment for 25 days significantly increased BrdU-IR cells versus the control and 7-NI 25 day treated group. In addition, nissl staining showed no cell death occurred in the dentate gyrus after 7-NI or L-NAME 25 day treatments. Our results demonstrate that chronic inhibition of NOS increases cell proliferation and has no effect on cell death in the dentate gyrus of the rat hippocampus, which suggests that NO may regulate cell proliferation in the dentate gyrus.
Park
Chan
C
Department of Anatomy and Neurobiology, Medical Science and Engineering Research Center for Reactive Oxygen Species, College of Medicine, Kyunghee University, Hoeki-Dong 1, Dongdaemun-Gu, 130-701, Seoul, South Korea.
Sohn
Youngjoo
Y
Shin
Ki Soon
KS
Kim
Junghye
J
Ahn
Heekyung
H
Huh
Youngbuhm
Y
D000818:Animals; D001973:Bromodeoxyuridine / Q000008:administration & dosage; D002455:Cell Division / Q000187:drug effects; D018891:Dentate Gyrus / Q000166:cytology / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry; D007191:Indazoles / Q000494:pharmacology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004791:Enzyme Inhibitors; D007191:Indazoles; D019001:Nitric Oxide Synthase; D001973:Bromodeoxyuridine; C080122:7-nitroindazole; D019331:NG-Nitroarginine Methyl Ester