[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.


CONCLUSIONS
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.
Tan
Yan
Y
Department of Pharmacology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.
Tang
Qiang
Q
Hu
Ben-Rong
BR
Xiang
Ji-Zhou
JZ
D000818:Animals; D001599:Berberine / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism; D010413:Penis / Q000187:drug effects / Q000378:metabolism*; D011817:Rabbits; D011863:Radioimmunoassay
D001599:Berberine; D000242:Cyclic AMP; D006152:Cyclic GMP