Inhibitory effects of ketamine and L--NAME on expression of c-fos and NOS in hypothalamic paraventricular nucleus after acute hypothermia and hypoxia in rats

摘要

Objective: To determine whether NMDA receptor activation mediates the expression of c--fos and NOS and study the relationship between the expression of c--fos and NOS in the hypothalamic paraventricularnucleus (PVN) following acute hypothermia and hypoxia. Methods: Fos immunohistochemistry, NADPH--d histochemistry and Fos/NADH--d double labeling were used. Results: Acute hypothermia and hypoxia induced the overexpression of on fos and NOS in PVN in rats. Pretreatment with ketamine, a NMDA receptor antagonist, resulted in partial inhibition of the expression of c--fos and NOS and that with blocker of NOS resulted in significant inhibition of the expression of c--fos. Conclusion: The activation of NMDA receptor is involved in the expression of c- fos and NOS in PVN in the rats subjected to acute hypothermia and hypoxia.Meanwhile, hypothalamic endogenous NO participates in adaptive reaction to hypothermia and hypoxia,which might be related to the modulation of c- fos expression.