Effects of N6-cyclopentyladenosine on afterdepolarizations and triggered activity induced by isoproterenol in guinea pig papillary muscle
Abstract
AIM: To investigate the effects of N6-cyclopentyladenosine (CPA, selective adenosine A1 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.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.
Keywords:
METHODS: The stable and reproducible early afterdepolarization (EAD) and delayed afterdepolarization (DAD) of guinea pig papillary muscle were induced by Iso 50 nmol.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.