Acute heat stress induces edema and nitric oxide synthase upregulation and down-regulates mRNA levels of the NMDAR1, NMDAR2A and NMDAR2B subunits in the rat hippocampus.
The influence of heat stress on constitutive isoform of neuronal nitric oxide synthase (cNOS) and NMDA receptor gene expression in hippocampus was examined in a rat model. Subjection of animals to 4 h heat stress at 38 degrees C resulted in a marked upregulation of cNOS in the hippocampus accompanied with a marked general expansion and edematous cell changes. On the other hand NMDA receptor messenger RNA encoding NMDAR1, NMDAR2A and NMDAR2B subunits showed a marked downregulation in the hippocampus of heat stressed rats compared to the controls. Our results show that upregulation of cNOS is instrumental in heat stress associated edema and cell injury. Furthermore, an increased production of NO as evident with upregulation of cNOS appears to be a key factor in the downregulation of NMDA receptor gene expression in heat stress.
Le Grevès
P
P
Department of Pharmaceutical Biosciences, Uppsala University, Sweden.
Sharma
H S
HS
Westman
J
J
Alm
P
P
Nyberg
F
F
D000208:Acute Disease; D000818:Animals; D015152:Blotting, Northern; D001929:Brain Edema / Q000209:etiology / Q000503:physiopathology*; D015536:Down-Regulation; D015870:Gene Expression; D006624:Hippocampus / Q000378:metabolism*; D006358:Hot Temperature; D008297:Male; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics* / Q000378:metabolism; D013312:Stress, Physiological / Q000503:physiopathology*; D015854:Up-Regulation
D010446:Peptide Fragments; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496322:Nos1 protein, rat