American Journal of Physiology-Cell Physiology · 1996 · 20 citations · 15 references
Life SciencesBiochemistryCell BiologyCell SignalingElectrophysiologySignal TransductionCardiac Ion ChannelsCardiac PhysiologyIon Channel ConductanceIon Channel PhysiologyIon Channel RegulationIon ChannelsCa2+ SignalingCardiac Ion Channel RegulationHill CoefficientHill KineticsInside-out Patch ClampOutside-out Patch ClampPotassium Channel ConductancePotassium Channel Physiology
Cyclic ADP-ribose (cADPR), an NAD metabolite, has been shown to be a messenger for Ca2+ mobilization from intracellular Ca2+ stores. However, the physiological role of ADP-ribose (ADPR), another metabolite of NAD, is not known. We examined the effects of cADPR and ADPR on the ATP-sensitive K+ channel (KATP) activity in rat ventricular myocytes by use of the inside-out patch-clamp configuration. ADPR, but not cADPR, inhibited the channel activity at micromolar range with an inhibitor constant (Ki) of 38.4 microM. The Hill coefficient was 0.9. ATP inhibited the K+ channel with a Ki of 77.8 microM, and the Hill coefficient was 1.8. Single-channel conductance was not affected by ADPR. These findings strongly suggest that ADPR may act as a regulator of KATP channel activity.
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ATP-regulated K+ channels in cardiac muscle
Akinori Noma · Nature · 1983 · 2.3K citations
Formation and Hydrolysis of Cyclic ADP-Ribose Catalyzed by Lymphocyte Antigen CD38
Maureen Howard, J. Christopher Grimaldi, J. Fernando Bazán et al. · Science · 1993 · 739 citations