title: A radiometric analysis of nitric oxide synthase activity in Hymenolepis diminuta.
abstract: The free radical nitric oxide (NO) is a neuronal messenger which is synthesized from L-arginine and O2 by nitric oxide synthase (NOS). In the synthesis NO and L-citrulline are produced in a stoichiometric 1:1 relation. The activity of NOS was analysed in homogenates of the rat tapeworm Hymenolepis diminuta by measuring the formation of L-[3H]citrulline after incubation with L-[3H]arginine. The nature of NOS in H. diminuta was determined by studying the effect of 3 types of NOS inhibitors: (1) L-NAME, (2) EGTA, (3) 7-nitro-indazole. All inhibitors caused a significant but not complete reduction in the formation of L-[3H]citrulline. The results are discussed against the background of nerve cells and fibres positive for NADPH-diaphorase staining in H. diminuta.
authors.affiliation: Institute of Parasitology, Russian Academy of Sciences, Moscow, Russia.
authors.forename: N B
authors.initials: NB
authors.lastname: Terenina
authors.forename: M V
authors.initials: MV
authors.lastname: Onufriev
authors.forename: N V
authors.initials: NV
authors.lastname: Gulyaeva
authors.forename: A M
authors.initials: AM
authors.lastname: Lindholm
authors.forename: M K
authors.initials: MK
authors.lastname: Gustafsson
mesh_terms: D000818:Animals; D002614:Chelating Agents / Q000737:chemistry; D002956:Citrulline / Q000032:analysis / Q000096:biosynthesis; D004533:Egtazic Acid / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000737:chemistry; D006926:Hymenolepis / Q000201:enzymology*; D007191:Indazoles / Q000737:chemistry; D019331:NG-Nitroarginine Methyl Ester / Q000737:chemistry; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D012588:Scintillation Counting
chemical_list: D002614:Chelating Agents; D004791:Enzyme Inhibitors; D007191:Indazoles; D002956:Citrulline; D009569:Nitric Oxide; D004533:Egtazic Acid; D019001:Nitric Oxide Synthase; C080122:7-nitroindazole; D019331:NG-Nitroarginine Methyl Ester