Activation of the iberiotoxin-sensitive BK sub(Ca) channels by salvianolic acid B of the porcine coronary artery smooth muscle cells

• Published in: European journal of pharmacology 2006-09, Vol.546 (1-3), p.28-35
• Main Authors: Lam, Francis Fu Yuen, Seto, Sai Wang, Kwan, Yiu Wa, Yeung, John Hok Keung, Chan, Paul
• Format: Article
• Language: English
• Subjects: Salvia miltiorrhiza
• ISSN: 0014-2999
• DOI: 10.1016/j.ejphar.2006.07.038

In this study, we examined the effects of Salvia miltiorrhiza (Danshen) crude extract, some of its lipid-soluble components (tanshinone I, tanshinon IIE sub(A), cryptotanshinone, dihydroisotanshinone I) and the water-soluble compounds (danshensu and salvianolic acid B) on the K super(+) channels such as the iberiotoxin-sensitive Ca super(2+)-activated K super(+) (BK sub(Ca)) channels and the glibenclamide-sensitive ATP-dependent K super(+) (IK sub(ATP)) channels of the porcine left anterior descending coronary artery smooth muscle cells. Cumulative application of salvianolic acid B (30-300 mu M) caused a l-NNA (100 mu M)- insensitive, potentiation of the outward BK sub(Ca) current amplitude with no apparent effect on the IK sub(ATP) channels opening. Salvianolic acid B (300 mu M) caused an ODQ (10 mu M, a guanylate cyclase inhibitor)-sensitive enhancement of the outward BK sub(Ca) current amplitude. In contrast, none of the other isolated chemical constituents of S. miltiorrhiza modified the openings of the two types of K super(+) channels studied. In conclusion, our results suggest that salvianolic acid B, a major hydrophilic constituent found in Radix S. miltiorrhiza, activated the opening of the BK sub(Ca) channels of the porcine coronary artery smooth muscle cells through the activation of guanylate cyclase without the involvement of the nitric oxide synthase activation.