title: Beneficial effect of crotamine in the treatment of myasthenic rats.
abstract: BACKGROUND
  Crotamine is a basic, low-molecular-weight peptide that, at low concentrations, improves neurotransmission in isolated neuromuscular preparations by modulating sodium channels. In this study, we compared the effects of crotamine and neostigmine on neuromuscular transmission in myasthenic rats.
  
  
  METHODS
  We used a conventional electromyographic technique in in-situ neuromuscular preparations and a 4-week treadmill program.
  
  
  RESULTS
  During the in-situ electromyographic recording, neostigmine (17 μg/kg) caused short-term facilitation, whereas crotamine induced progressive and sustained twitch-tension enhancement during 140 min of recording (50 ± 5%, P < 0.05). On the treadmill evaluation, rats showed significant improvement in exercise tolerance, characterized by a decrease in the number of fatigue episodes after 2 weeks of a single-dose treatment with crotamine.
  
  
  CONCLUSIONS
  These results indicate that crotamine is more efficient than neostigmine for enhancing muscular performance in myasthenic rats, possibly by improving the safety factor of neuromuscular transmission.
authors: Departamento de Farmacologia, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, São Paolo, Brazil.
authors: Saraguaci
authors: S
authors: Hernandez-Oliveira e Silva
authors: Sandro
authors: S
authors: Rostelato-Ferreira
authors: Thomaz Augusto Alves
authors: TA
authors: Rocha-e-Silva
authors: Priscila
authors: P
authors: Randazzo-Moura
authors: Cháriston André
authors: CA
authors: Dal-Belo
authors: Eladio Flores
authors: EF
authors: Sanchez
authors: Caroline R
authors: CR
authors: Borja-Oliveira
authors: Léa
authors: L
authors: Rodrigues-Simioni
mesh_terms: D000818:Animals; D002800:Cholinesterase Inhibitors / Q000627:therapeutic use*; D003435:Crotalid Venoms / Q000627:therapeutic use*; D004353:Drug Evaluation, Preclinical; D004576:Electromyography; D017079:Exercise Tolerance / Q000187:drug effects; D006614:Hindlimb; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects; D020720:Myasthenia Gravis, Autoimmune, Experimental / Q000188:drug therapy*; D009388:Neostigmine / Q000627:therapeutic use*; D009469:Neuromuscular Junction / Q000187:drug effects; D051381:Rats; D011917:Rats, Inbred Lew; D009435:Synaptic Transmission / Q000187:drug effects; D016896:Treatment Outcome
chemical_list: D002800:Cholinesterase Inhibitors; D003435:Crotalid Venoms; D009388:Neostigmine; C010563:crotamine