title: Simultaneous measurement of nitrite and nitrate levels as indices of nitric oxide release in the cerebellum of conscious rats.
abstract: We examined the modulation of nitric oxide production in vivo by measuring levels of nitrite (NO2-) and nitrate (NO3-) in the dialysate of the cerebellum in conscious rats, by using an in vivo brain microdialysis technique. The levels of both NO2- and NO3- were decreased by the intraperitoneal injection of NG-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthase, whereas NG-nitro-D-arginine methyl ester had no effect. L-Arginine by itself increased NO2- and NO3- levels and diminished the reduction of their levels caused by NG-nitro-L-arginine methyl ester. Direct infusion of L-glutamate, N-methyl-D-aspartate, or KCl into the cerebellum through a dialysis probe resulted in an increase in NO2- and/or NO3- levels. The effects of N-methyl-D-aspartate and KCl were dependent on extracellular calcium. Furthermore, the stimulatory effects of L-glutamate and N-methyl-D-aspartate were inhibited by NG-nitro-L-arginine methyl ester and (+/-)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP), an N-methyl-D-aspartate receptor antagonist. These results suggest that NO2- and NO3- levels may be related to nitric oxide production in vivo.
authors.affiliation: Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University School of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamada
authors.forename: T
authors.initials: T
authors.lastname: Nabeshima
mesh_terms: D000818:Animals; D001120:Arginine / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D002531:Cerebellum / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005110:Extracellular Space / Q000378:metabolism; D018698:Glutamic Acid / Q000494:pharmacology; D008297:Male; D016202:N-Methylaspartate / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009566:Nitrates / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009573:Nitrites / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D004791:Enzyme Inhibitors; D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide; D018698:Glutamic Acid; D016202:N-Methylaspartate; D001120:Arginine; D019001:Nitric Oxide Synthase; D002118:Calcium; D019331:NG-Nitroarginine Methyl Ester