Involvement of nitric oxide in the pathophysiology of acute heat stress in the rat. Influence of a new antioxidant compound H-290/51.
The possibility that nitric oxide (NO) is involved in the pathophysiology of brain injury caused by heat stress (HS) was examined using immunohistochemistry of a constitutive isoform of neuronal nitric oxide synthase (c-NOS) in a rat model. In addition, to discover the role of oxidative stress in inducing c-NOS activity in HS, the effect of a new antioxidant H-290/51 on HS-induced expression of c-NOS immunoreactivity was examined. Subjection of conscious young animals to a 4-h HS in a biological oxygen demand (BOD) incubator at 38 degrees C resulted in marked upregulation of c-NOS in the cerebral cortex and hippocampus of stressed rats compared to normal rats kept at room temperature (21 +/- 1 degrees C). The c-NOS immunoreactivity was found in distorted neurons located in the edematous regions not normally showing c-NOS activity. Pretreatment with H-290/51 significantly attenuated the upregulation of c-NOS in animals subjected to HS, and the signs of neuronal distortion and edema were less pronounced. These results suggest that HS has the capacity to induce upregulation of c-NOS, and these effects can be reduced by prior treatment with H-290/51, indicating a possible neuroprotective effect of antioxidants in thermal brain injury.
Sharma
H S
HS
Department of Anatomy, Uppsala University, Sweden. sharma@anatomi.uu.se
Westman
J
J
Alm
P
P
Sjöquist
P O
PO
Cervós-Navarro
J
J
Nyberg
F
F
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001930:Brain Injuries / Q000201:enzymology; D002540:Cerebral Cortex / Q000201:enzymology; D018882:Heat Stress Disorders / Q000201:enzymology / Q000503:physiopathology*; D006624:Hippocampus / Q000201:enzymology; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D000975:Antioxidants; C088233:H290-51; D007211:Indoles; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase