The effects of endothelin-1 (ET-1) on whole-cell cardiac PKA-dependent Cl- currents (ICl) were investigated using patch clamp techniques. ET-1 inhibited the isoproterenol-induced ICl with a half-maximally effective concentration of approximately 1 nM. ET-1 also inhibited the forskolin-induced current in a similar concentration range. The effects of ET-1 were abolished by pre-treatment of the cells with pertussis toxin. Since ET-1 was ineffective at inhibiting the ICl induced by internal dialysis with cyclic AMP, it is unlikely that the Gi-protein had a direct effect on channel gating or phosphorylation of the channel by PKA. It is concluded that ET-1 inhibited the cardiac PKA-dependent ICl by attenuating activation of adenylate cyclase and that this effect was mediated by a pertussis toxin-sensitive G-protein, presumably Gi.
|Original language||English (US)|
|Journal||The Japanese journal of physiology|
|Volume||44 Suppl 2|
|State||Published - 1994|
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