Effects of N6-cyclopentyladenosine on afterdepolarizations and triggered activity induced by isoproterenol in guinea pig papillary muscle
Li, Y.L.; He, R.R.
Zhongguo Yao Li Xue Bao 16(2): 163-168
1995
ISSN/ISBN: 0253-9756 PMID: 7597921 Document Number: 441790
AIM: To investigate the effects of N-6-cyclopentyladenosine (CPA, selective adenosine A-1 receptor agonist) on afterdepolarizations and triggered activity induced by isoproterenol (Iso) in guinea pig papillary muscle. METHODS: The stable and reproducible early afterdepolarization (EAD) and delayed afterdepolarization (DAD) of guinea pig papillary muscle were induced by Iso 50 nmol cntdot L-1. The parameters of EAD and DAD were recorded using intracellular microelectrodes. RESULTS: CPA markedly attenuated the development of EAD, DAD, and triggered activity (TA) induced by Iso in guinea pig papillary muscle. The inhibitory effects of CPA on Iso-induced EAD and DAD were antagonized by 8-phenyltheophylline (8-PT) and glibenclamide (Gli). CONCLUSION: ATP-sensitive K+ channels were involved in Iso-induced EAD and DAD, and in the inhibitory effects of CPA on EAD and DAD.