title: Role of nitric oxide in myotoxic activity induced by crotoxin in vivo.
abstract: This study was aimed to determine the role of nitric oxide on the skeletal myotoxic activity induced by crotoxin, the major component of the venom of Crotalus durissus terrificus. Rats were treated with N(G)-nitro-L-arginine methyl ester (L-NAME), a non-selective inhibitor of nitric oxide synthase or vehicle for 4 days, and on the 5th day received an intramuscular injection of crotoxin into the tibialis anterior muscle. Rats were also treated with aminoguanidine bicarbonate salt or 7-nitroindazole, inhibitors of the inducible and neuronal isoforms of nitric oxide synthase, respectively, for 4 days and on the 5th day injected with crotoxin. All treated groups were sacrificed 24 h after injection of crotoxin. Tibialis anterior and soleus muscles were removed, frozen and stored in liquid nitrogen. Histological sections were stained with toluidine blue and assayed for acid phosphatase. The results show that L-NAME significantly minimizes myonecrosis induced by crotoxin and both aminoguanidine and 7-nitroindazole partially prevented myonecrosis induced by crotoxin. Based on the present results we conclude that nitric oxide is a very important intracellular signaling molecule that mediates crotoxin myotoxic activity.
authors.affiliation: Department of Histology/Embriology, Institute of Biomedical Sciences, University of São Paulo, Av Lineu Prestes 1524, ICB I, 05508-900 São Paulo, Brazil.
authors.forename: E H
authors.initials: EH
authors.lastname: Miyabara
authors.forename: R C
authors.initials: RC
authors.lastname: Tostes
authors.forename: H S
authors.initials: HS
authors.lastname: Selistre-de-Araújo
authors.forename: M S
authors.initials: MS
authors.lastname: Aoki
authors.forename: A S
authors.initials: AS
authors.lastname: Moriscot
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001938:Brazil; D017839:Crotalus; D003439:Crotoxin / Q000378:metabolism / Q000633:toxicity*; D006146:Guanidines / Q000494:pharmacology; D006652:Histological Techniques; D007191:Indazoles / Q000494:pharmacology; D018482:Muscle, Skeletal / Q000473:pathology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009336:Necrosis; D009569:Nitric Oxide / Q000378:metabolism* / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000502:physiology
chemical_list: D006146:Guanidines; D007191:Indazoles; D009569:Nitric Oxide; D003439:Crotoxin; D019001:Nitric Oxide Synthase; C004479:pimagedine; C080122:7-nitroindazole; D019331:NG-Nitroarginine Methyl Ester