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  • Title: Effects of dopamine on ATP-sensitive potassium channels in porcine coronary artery smooth-muscle cells.
    Author: Kawano H, Kawano T, Tanaka K, Eguchi S, Takahashi A, Nakaya Y, Oshita S.
    Journal: J Cardiovasc Pharmacol; 2008 Feb; 51(2):196-201. PubMed ID: 18287888.
    Abstract:
    BACKGROUND: Dopamine is reported to be a coronary vasodilator; however, the exact mechanism of dopamine action in the coronary circulation remains unclear. In this study, we hypothesized that dopamine-induced activation of coronary ATP-sensitive potassium (KATP) channels may be associated with coronary vasodilation. We therefore investigated the direct effects of dopamine on coronary KATP-channel activity. METHODS: We used patch-clamp configurations to investigate the effects of dopamine on coronary KATP-channel activity. RESULTS: Application of dopamine (10 to 10 M) to the bath solution during cell-attached recordings induced a concentration-dependent increase in KATP-channel activity. In contrast, dopamine failed to activate KATP channels in inside-out patches. Dopamine-induced coronary KATP-channel currents in cell-attached patches were inhibited by pretreatment with the selective D1-like antagonist, Sch-23390, but they were not influenced by the selective D2-like antagonist, domperidone, or the beta-adrenergic receptor antagonist, propranolol. The selective D1-like agonist, SKF-38393, and the adenylyl cyclase activator, forskolin, mimicked the dopamine effects on coronary KATP channels. Furthermore, pretreatment with an inhibitor of protein kinase A, Rp-cAMPS, abolished the dopamine-induced KATP-channel activation. CONCLUSIONS: This study demonstrates that dopamine activates coronary KATP channels via signal transduction involving the D1-like dopaminergic receptor-protein kinase A-signaling pathway.
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