Water-deprivation-induced expression of neuronal nitric oxide synthase in the hypothalamic paraventricular nucleus of rat.
This study was conducted to define the molecular mechanism by which dehydration induces expression of neuronal nitric oxide synthase (nNOS) in the hypothalamic paraventricular nucleus (PVN). Rats were deprived from water for 48 hr and then sacrificed immediately or 1 hr after ad libitum access to water. Another group of rats had free access to food and water and was included as euhydrate control group. The PVN sections fixed with 4% paraformaldehyde were processed for nNOS immunohistochemistry and NADPH-diaphorase (NADPH-d)/pCREB or NADPH-d/c-Fos double staining. nNOS-ir neurons significantly increased with water deprivation and decreased with rehydration, both in the posterior magnocellular (pM)- and the medial parvocellular (mP)-PVN. Most NADPH-d histostained neurons in the PVN appeared to exhibit pCREB-ir as well. Water deprivation markedly increased, and rehydration decreased, NADPH-d/pCREB neurons both in the pM- and in the mP-PVN. Gel shift assay demonstrated that dehydration may promote CREB binding to nNOS promoter in the PVN neurons. Significant amounts of NADPH-d-stained neurons in the PVN of water-deprived rats (67-68% in both the mP and the pM) exhibited c-Fos-ir. NADPH-d/c-Fos neurons in the pM-PVN were increased by water deprivation but not changed by rehydration. NADPH-d/c-Fos double-stained neurons in the mP-PVN did not significantly change depending on different water conditions. These results suggest that pCREB may play a role in dehydration-induced nNOS gene expression in the PVN neurons, and c-Fos might not be implicated in the regulatory pathway.
Ryu
Vitaly
V
Department of Oral and Maxillofacial Surgery, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea.
Lee
Jong-Ho
JH
Um
Ji Won
JW
Yoo
Sang Bae
SB
Lee
Jisun
J
Chung
Kwang Chul
KC
Jahng
Jeong Won
JW
D000818:Animals; D050882:CREB-Binding Protein / Q000096:biosynthesis*; D003345:Corticosterone / Q000097:blood; D024202:Electrophoretic Mobility Shift Assay; D015870:Gene Expression; D007150:Immunohistochemistry; D008297:Male; D009252:NADPH Dehydrogenase / Q000096:biosynthesis; D052248:Nitric Oxide Synthase Type I / Q000096:biosynthesis*; D010286:Paraventricular Hypothalamic Nucleus / Q000201:enzymology*; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D014868:Water Deprivation / Q000502:physiology*
D016760:Proto-Oncogene Proteins c-fos; D052248:Nitric Oxide Synthase Type I; D009252:NADPH Dehydrogenase; D050882:CREB-Binding Protein; D003345:Corticosterone