马齿苋水提取物平喘作用与β受体和M受体的关系

摘要

目的：观察马齿苋水提取物（ water extract of Portulaca oleracea L， WEPO）平喘作用与β和M受体的关系，探讨其平喘作用机制。方法选用体质量2．0～2．5 kg家兔，制备离体气管环。以气管平滑肌收缩频率、幅度为指标，观察WEPO对气管平滑肌活力的影响。以氨茶碱（ Ami）为阳性对照药，以普萘洛尔（ Pro）为β受体阻断剂，观察WEPO平喘作用与β受体的关系，以氯乙酰胆碱（ AChCl）为M受体激动剂、阿托品（ Atr）为M受体阻断剂，观察WEPO平喘作用与M受体的关系。结果①WEPO各剂量组药后家兔离体气管平滑肌收缩频率、幅度均显著低于药前（ P＜0．05，＜0．01）。②Pro＋WEPO组药后气管平滑肌收缩频率、幅度显著高于WEPO组，二者比较差异有统计学意义（P＜0．01）。③AChCl组药后气管平滑肌收缩频率、幅度均显著高于药前（P＜0．01）。④WEPO＋AChCl组药后气管平滑肌收缩频率、幅度与AChCl组药后比较差异无统计学意义（P＞0．05）。⑤Atr＋WEPO组药后上述指标与WEPO组药后比较差异无统计学意义（P＞0．05）。结论 WEPO平喘作用与松弛气管平滑肌有关，兴奋β受体是其松弛气管平滑肌作用机制之一，与M受体无关。%Objective To study the anti-asthma mechanism of water extract of Portulaca oleracea L( WEPO) related toβand M receptors.Methods Rabbits of 2.0 -2.5 kg were selected,whose isolated tracheal rings were prepared.The effect of WEPO on tracheal smooth muscle tension was evaluated using tracheal smooth muscle contraction frequency and contraction amplitude as indexes.Aminophylline( Ami) was used as a positive control medicine and propranolol( Pro) as theβreceptor blocking agent to observe the relaxation effect on tracheal smooth muscle of WEPO related to βreceptors. Acetylcholine chloride( AChCl) was used as the agonist for M receptors and atronine( Atr) as the M receptor blocking agent to observe the relaxation effect on tracheal smooth muscle of WEPO related to M receptors.Results ①The contraction frequency and amplitude of isolated tracheal smooth muscle in each dose group of WEPO were significantly lower after treatment.The difference was statistically significant(P <0.05,P <0.01).②The baseline,contraction frequency and amplitude of isolated tracheal smooth in Pro +WEPO group were higher than in WEPO group and the difference was statistically significant (P<0.01).③The baseline, contraction frequency and amplitude of isolated tracheal smooth muscle in AChCl group were significantly higher after treatment(P<0.01)significantly.④The baseline, contraction frequency and amplitude in WEPO +AChCl group were not different from those in AChCl group ( P >0.05 ) .⑤These indexes in Atr+WEPO group were not different those in WEPO group ( P >0.05 ) .Conclusion WEPO has relaxation effect on isolated tracheal smooth muscle of rabbits,which is related toβreceptors rather than M receptors.