Pharmacodynamic changes with vecuronium in sepsis are associated with expression of 7-and -nicotinic acetylcholine receptor in an experimental rat model of neuromyopathy

Resistance to non-depolarizing neuromuscular blocking agents induced by sepsis is associated with the qualitative change in the nicotinic acetylcholine receptor (nAChR). This study aims to investigate the effects of sepsis on the neuromuscular block properties of vecuronium in relation to the expression of fetal and neuronal 7 type nAChR. Male SpragueDawley rats were randomly divided into sham and sepsis groups. Sepsis was induced by caecal ligation and puncture (CLP). The rats were injected i.v. with ulinastatin or normal saline on Day 10. Neuromuscular block properties of vecuronium were evaluated and neuromuscular function was assessed by electromyography on Days 1, 3, 7, and 14 after CLP. Expression of fetal and neuronal type 7-nAChR on the tibialis anterior muscle was assessed using immunohistochemistry and western blot. The mRNA encoding for - and 7 subunits was evaluated by real-time polymerase chain reaction. The half maximal inhibitory response of vecuronium in the sepsis group significantly increased, peaked on Day 7, and then declined on Day 14 (P0.05). The neuromuscular function decreased with increasing postoperation time in the sepsis group (P0.05). Sepsis significantly increased the expression of - and 7-nAchR along with expression of - and 7 subunits mRNA, peaked on Day 7, and declined on Day 14 (P0.05). Ulinastatin suppressed the expression of receptor protein and mRNA encoding for - and 7 subunits (P0.05). Pharmacodynamic changes with vecuronium seem to be associated with the expression of - and 7-nAChR in the skeletal muscle. Ulinastatin can improve this effect by inhibiting the expression of these receptors.