A radiometric analysis of nitric oxide synthase activity in Hymenolepis diminuta.
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.
Terenina
N B
NB
Institute of Parasitology, Russian Academy of Sciences, Moscow, Russia.
Onufriev
M V
MV
Gulyaeva
N V
NV
Lindholm
A M
AM
Gustafsson
M K
MK
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
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