小檗碱对离体家兔阴茎海绵体cGMP和cAMP水平的影响

Effects of Berberine on Cyclic GMP and Cyclic AMP Levels in Rabbit Corpus Cavernosum in vitro

目的:观察小檗碱(berberine,Ber)对离体家兔阴茎海绵体平滑肌组织中环磷酸鸟苷(cGMP)和环磷酸腺苷(cAMP)水平的影响。方法:采用125I放射免疫测定法,以西地那非(sildenafil,Sil)为阳性对照,测定不同浓度的Ber对离体家兔阴茎海绵体平滑肌组织中cGMP和cAMP水平的影响。结果:Ber能直接升高cGMP的含量(P<0.05),EC50为1.75μmol/L,但对cAMP含量无显著影响。在cGMP激发剂硝普钠(SNP)存在下,Ber和Sil均能浓度依赖性地提高海绵体组织中cGMP浓度(P<0.01),促进cGMP生成的EC50分别为1.32、0.67μmol/L。同样的条件下,Ber和Sil对cAMP的浓度均无显著影响(P>0.05)。在cAMP激发剂前列腺素E1(PGE1)刺激下,Ber和Sil也能够提高海绵体组织中cAMP的浓度(P<0.01),表现出浓度依赖性,促进cAMP生成的EC50分别为4.90、6.53μmol/L。结论:Ber可提高阴茎海绵体平滑肌中cGMP、cAMP的浓度,此效应可能为其舒张阴茎海绵体的潜在机制。

Objective: To further investigate the action mechanisms of berberine (Ber), and assess the effects of Ber on the in vitro formation of cGMP and cAMP in the isolated rabbit corpus cavernosum. Methods: Isolated segments of the rabbit corpus cavernosum were exposed to different concentrations of Ber, and the dosage-dependent accumulations of cGMP and cAMP were determined in the tissue samples by means of ~ 125I radioimmunoassay. Responses of the isolated tissue preparations to Ber were compared with those obtained with the reference compound sildenafil (Sil). Results: Ber increased cGMP concentrations directly (P< 0.05). In the presence of sodium nitroprusside (SNP), a stimulatory agent of cGMP, both Ber and Sil increased cGMP with increasing dosage (P< 0.01), the EC 50 values being 1.32 and 0.67 μmol/L respectively. With the same concentration, neither Ber nor Sil influenced the cAMP level significantly (P> 0.05). In the presence of PGE 1, a stimulator of cAMP, Ber and Sil also raised the cAMP level concentration (P< 0.01), the EC 50 values being 4.90 (Ber) and 6.53 (Sil) μmol/L respectively. Conclusion: Ber can increase cGMP and cAMP concentrations in the corpus cavernosum smooth muscles, which may contribute to its action of relaxing corpus cavernosum smooth muscles.