小檗碱对离体家兔阴茎海绵体cGMP和cAMP水平的影响

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。

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

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, values being 1.32 and 0.67 micromol/L respectively. With the same concentration, neither Ber nor Sil influenced the cAMP level significantly (P > 0.05). In the presence of PGE1, a stimulator of cAMP, Ber and Sil also raised the cAMP level concentration (P < 0.01 ), the EC, values being 4.90 (Ber) and 6.53 (Sil) micromol/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.