Internalization and recycling profiles ofμ-and dimerizedμ-δopioid receptors induced by remifentanil : implication of acute tolerance of remifentanil.

大剂量输注瑞芬太尼可产生急性耐受。我们研究了小剂量和大剂量瑞芬太尼对μ-阿片受体（μOR）和二聚化μ-δOR的内化和再循环的影响。不同浓度瑞芬太尼的μOR内化率差异无统计学意义，μ-δOR内化率呈浓度依赖性增加。在大剂量瑞芬太尼刺激下，μOR和二聚化μ-δOR的再循环率降低，在相同浓度下，瑞芬太尼内化的μ-δOR再循环率高于内化的μOR。这些发现可能解释了大剂量瑞芬太尼诱导的急性耐受。

Remifentanil might develop acute tolerance when infused at large dose. We investigated the effects of small-and large-doses of remifentanil on the internalization and recycling profiles of bothμ-opioid receptors(μOR) and dimerizedμ-δOR. There was no significant difference among the rate of internalizedμOR by remifentanil at any concentrations, whereas the percentages of internalizedμ-δOR by remifentanil increased in a concentration-dependent manner. The rate of recycling ofμOR and dimerizedμ-δOR was decreased when stimulated by remifentanil at large doses.μ-δOR internalized by remifentanil were recycled more thanμOR internalized at the same concentrations. These findings may account for the acute tolerance induced by large-doses of remifentanil.