Role of different nicotinic acetylcholine receptor subtypes in skeletal muscles in sepsis-related nerve-muscle dysfunction in septic rats: neuroelectrophysiology / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of different nicotinic acetylcholine receptor ( nAChR) subtypes in skeletal muscles in sepsis-related nerve-muscle dysfunction in septic rats by neuroelectrophysiol-ogy. Methods SPF adult male Sprague-Dawley rats, weighing 200-220 g, aged 2-3 months, were stud-ied. Sepsis was induced by cecal ligation and puncture in chloral hydrate-anesthetized rats. Twelve portions of sciatic nerve-tibialis anterior muscles taken at day 3 after successful establishment of the sepsis modelserved as group S. Another 12 portions of sciatic nerve-tibialis anterior muscles of normal rats served as group C. The endplate potential ( EPP ) was monitored by intracellular microelectrode recording. Six por-tions of nerve-muscle samples were incubated with the adult nAChR (ε-nAChR ) specific antagonist wa-glerin-1 at a concentration of 1 μmol∕L, the fetal nAChR (γ-nAChR) specific antagonist αA-OIVA at a concentration of 250 nmol∕L and neuronal nAChR (α7-nAChR) antagonist methyllycaconitine ( MLA) at a final concentration of 6 nmol∕L. The amplitude of EPP was recorded at 15 min of incubation, and the differ-ence in the amplitude of EPP (&Delta;EPP) and changing rate of EPP (&Delta;EPP％) were calculated. Another 6 portions of samples were incubated for 15 min with the Kreb mixture of waglerin-1 and 250 nmol∕LαA-OIVA at a final concentration of 1 μmol∕L, the Kreb mixture of waglerin-1 and 6 nmol∕L MLA at a final concen-tration of 1 μmol∕L, and the Kreb mixture of αA-OIVA and 6 nmol∕L MLA at a final concentration of 250 nmol∕L, and then the amplitude of EPP was recorded. Washout was performed with antagonist free Kreb so-lution for 15 min between treatments with different blockers. Results Compared with group C, &Delta;EPP and&Delta;EPP％ were significantly decreased after antagonizing ε-nAChR, &Delta;EPP％ was decreased after antagoni-zing γ-nAChR, &Delta;EPP and &Delta;EPP％ were increased after antagonizing α7-nAChR, the amplitude of EPP was increased after antagonizingε-nAChR+γ-nAChR andε-nAChR+α7-nAChR, and the amplitude of EPP was decreased after antagonizing γ-nAChR+α7-nAChR (P<0. 05). &Delta;EPP and &Delta;EPP％ were significantly higher after antagonizing α7-nAChR than after antagonizingγ-nAChR in group S ( P<0. 05) . The EPP was significantly lower after antagonizingε-nAChR+α7-nAChR than after antagonizingε-nAChR+γ-nAChR ( P<0. 05) . Conclusion Weakened function of ε-nAChR and enhanced function of α7-nAChR in the mem-brane of the end-plate in skeletal muscle are the main reasons for sepsis-related nerve-muscle dysfunction in septic rats, and the role is comparable between them.