title: TNFα increases resting potential in isolated fibres from rat peroneus longus by a PKC mediated mechanism: involvement in ICU acquired polyneuromyopathy.
abstract: OBJECTIVE
  Our aim was to investigate the effect of TNFα on muscle resting potential (RP) and then in muscle excitability and to demonstrate another mechanism implicated in intensive care units (ICU) acquired polyneuromyopathy.
  
  
  METHODS
  Experiments were carried out on adult female Wistar rats. After isolation of muscle fibres from peroneus longus, influence of TNFα was tested on RP by using intracellular microelectrodes. Digoxin and chelerythrin were used to determine the mechanism of TNFα action.
  
  
  RESULTS
  First, we found that TNFα induced a concentration dependent increase of muscle RP and that this mechanism, which was blocked by digoxin, was due to an effect on the Na/K ATPase. As it was also blocked by chelerythrin it was concluded that this effect was mediated by PKC activation of the Na/K ATPase.
  
  
  CONCLUSIONS
  We demonstrated that TNFα leads to a PKC mediated increase in muscle RP. Depolarization needed to reach the threshold voltage for muscle action potential should then be higher and this could be involved in the decrease in muscle excitability observed in acquired polyneuromyopathy.
authors: CHU Brest, Pôle Anesthésie Réanimation, Université de Brest, Faculté de Médecine et des Sciences de la Santé, EA 4326, Laboratoire de Physiologie, Brest, F-29200, France.
authors: Maité
authors: M
authors: Guillouet
authors: Gildas
authors: G
authors: Gueret
authors: Fabrice
authors: F
authors: Rannou
authors: Marie-Agnès
authors: MA
authors: Giroux-Metges
authors: Maxime
authors: M
authors: Gioux
authors: Charles C
authors: CC
authors: Arvieux
authors: Jean-Pierre
authors: JP
authors: Pennec
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D008564:Membrane Potentials / Q000187:drug effects*; D008839:Microelectrodes; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D014409:Tumor Necrosis Factor-alpha