title: Activation of the iberiotoxin-sensitive BKCa channels by salvianolic acid B of the porcine coronary artery smooth muscle cells.
abstract: In this study, we examined the effects of Salvia miltiorrhiza (Danshen) crude extract, some of its lipid-soluble components (tanshinone I, tanshinone II(A), cryptotanshinone, dihydroisotanshinone I) and the water-soluble compounds (danshensu and salvianolic acid B) on the K(+) channels such as the iberiotoxin-sensitive Ca(2+)-activated K(+) (BK(Ca)) channels and the glibenclamide-sensitive ATP-dependent K(+) (IK(ATP)) channels of the porcine left anterior descending coronary artery smooth muscle cells. Cumulative application of salvianolic acid B (30-300 microM) caused a l-NNA (100 microM)-insensitive, potentiation of the outward BK(Ca) current amplitude with no apparent effect on the IK(ATP) channels opening. Salvianolic acid B (300 microM) caused an ODQ (10 microM, a guanylate cyclase inhibitor)-sensitive enhancement of the outward BK(Ca) current amplitude. In contrast, none of the other isolated chemical constituents of S. miltiorrhiza modified the openings of the two types of K(+) 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(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.
authors.affiliation: Li Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, PR China.
authors.forename: Francis Fu Yuen
authors.initials: FF
authors.lastname: Lam
authors.forename: Sai Wang
authors.initials: SW
authors.lastname: Seto
authors.forename: Yiu Wa
authors.initials: YW
authors.lastname: Kwan
authors.forename: John Hok Keung
authors.initials: JH
authors.lastname: Yeung
authors.forename: Paul
authors.initials: P
authors.lastname: Chan
mesh_terms: D000818:Animals; D001572:Benzofurans / Q000494:pharmacology*; D003331:Coronary Vessels / Q000187:drug effects / Q000378:metabolism; D019806:Cromakalim / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D010069:Oxadiazoles / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000494:pharmacology*; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects* / Q000378:metabolism; D011810:Quinoxalines / Q000494:pharmacology; D011955:Receptors, Drug / Q000187:drug effects / Q000378:metabolism; D027561:Salvia miltiorrhiza; D013552:Swine; D053630:Depsides
chemical_list: D001572:Benzofurans; D019806:Cromakalim; D004365:Drugs, Chinese Herbal; D004791:Enzyme Inhibitors; D005905:Glyburide; D006162:Guanylate Cyclase; D019001:Nitric Oxide Synthase; D019335:Nitroarginine; D010069:Oxadiazoles; D010455:Peptides; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D011810:Quinoxalines; D011955:Receptors, Drug; C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; C067662:glibenclamide receptor; C028972:dan-shen root extract; C064719:iberiotoxin; C076944:salvianolic acid B; D053630:Depsides