title: The role of neuronal nitric oxide synthase on hypobaric hypoxia-induced antinociception in writhing test.
abstract: It has been reported that hypobaric hypoxia exposure by high altitude is responsible for neuropsychological impairment. In the present study, we examined an effect of hypobaric hypoxia on the writhing test. The ICR mice were exposed in hypobaric chamber with several altitudes (5000, 10,000 or 20,000 ft) for 1 or 2 h, and then immediately injected intraperitoneally (i.p.) with 1% acetic acid for writhing test. Our results show that both 10,000 ft and 20,000 ft exposure induce antinociceptive effect in writhing test, but 5,000 ft does not. In addition, this antinociceptive effect was abolished by L-NAME (nitric oxide synthase inhibitor) pre-treated intraperitoneally, but not naloxone (non-specific opioid receptor antagonist). Furthermore, we examined that neuronal NOS immunoreactivities in the hypothalamus (paraventricular nucleus and arcuate nucleus) were increased by hypobaric hypoxic exposure (10,000ft). These results suggest that hypobaric hypoxic-induced antinociception may be associated with neuronal NOS IR in the hypothalamus.
authors.affiliation: Department of Pharmacology, Institute of Natural Medicine, Hallym University, ChunCheon, Korea.
authors.forename: Seung-Min
authors.initials: SM
authors.lastname: Choi
authors.forename: Soo-Young
authors.initials: SY
authors.lastname: Chung
authors.forename: Chang-Ahn
authors.initials: CA
authors.lastname: Seol
authors.forename: Jin-Gon
authors.initials: JG
authors.lastname: Sul
authors.forename: Min-Soo
authors.initials: MS
authors.lastname: Kwon
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000201:enzymology*; D000860:Hypoxia / Q000201:enzymology* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D052248:Nitric Oxide Synthase Type I / Q000502:physiology*; D010147:Pain Measurement / Q000379:methods*; D010286:Paraventricular Hypothalamic Nucleus / Q000201:enzymology*; D011897:Random Allocation
chemical_list: D052248:Nitric Oxide Synthase Type I