Effects of skeletal muscle denervation on the potency of succinylcholine.

The aim of the present study was to investigate the time‑dependent effects of denervation on the sensitivity of skeletal muscles to the relaxant succinylcholine (SuCh) and to assess the possible association of the de novo expression of γ‑acetylcholine receptor (AChR). Innervated as well as denervated mouse muscle cells and human embryonic kidney (HEK293) cells expressing γ‑AChR and ε‑AChR were used in the present study. The effects of SuCh on the current of nicotinic (n)AChRs were examined using a whole‑cell patch clamp technique. Compared with innervated skeletal muscle cells, the SuCh concentration producing 50% of the maximal response (EC50) were decreased by 20, 56, 73, 66, 60 and 62% (P<0.05), and current responses induced by 30 µM SuCh were increased by 1.9‑, 4.6‑, 9.4‑, 7.1‑, 5.2‑ and 5.1‑fold (P<0.05) at days 1, 4, 7, 14, 21 and 28 after denervation, respectively. However, SuCh was equipotent regarding γ‑AChR and ε‑AChR (P>0.05). These results indicated that short‑term denervation led to a change in the sensitivity of muscle cells to SuCh, which, however, was unlikely to be associated with the de novo expression of γ‑AChR.