Pathological prolongation of action potential duration as a cause of the reduced alpha-adrenoceptor-mediated negative inotropy in streptozotocin-induced diabetic mice myocardium

• Main Authors: Haruna Kanae, Shogo Hamaguchi, Yumi Wakasugi, Taichi Kusakabe, Keisuke Kato, Iyuki Namekata, Hikaru Tanaka
• Format: Article
• Language: English
• Published: Elsevier 2017-11-01
• Series: Journal of Pharmacological Sciences
• Subjects: Diabetic mellitus; Action potential duration; α-Adrenoceptor
• Online Access: http://www.sciencedirect.com/science/article/pii/S1347861317301743
• ISSN: 1347-8613

Effect of pathological prolongation of action potential duration on the α-adrenoceptor-mediated negative inotropy was studied in streptozotocin-induced diabetic mice myocardium. In streptozotocin-treated mouse ventricular myocardium, which had longer duration of action potential than that in control mice, the negative inotropic response induced by phenylephrine was smaller than that in control mice. 4-Aminopyridine prolonged the action potential duration and decreased the negative inotropy in control mice. Cromakalim shortened the action potential duration and increased the negative inotropy in streptozotocin-treated mice. These results suggest that the reduced α-adrenoceptor-mediated inotropy in the diabetic mouse myocardium is partly due to its prolonged action potential.