Characterization of voltage-dependent gating of P2X2 receptor/channel.
The role of a voltage-dependent gate of recombinant P2X2 receptor/channel was investigated in Xenopus oocytes. When a voltage step to -110 mV was applied from a holding potential of -50 mV, a gradual increase was observed in current evoked by 30 microM ATP. Contribution of this voltage-dependent component to total ATP-evoked current was greater when the current was evoked by lower concentrations of ATP. The voltage-dependent gate closed upon depolarization, and half the gates were closed at -80 mV. On the other hand, a potential at which half the gates opened was about -30 mV or more positive, which was determined using a series of hyperpolarization steps. The results of the present study suggest that the voltage-dependent gate behavior of P2X2 receptor is not due to simple activation and deactivation of a single gate, but rather due to transition from a low to a high ATP affinity state.
Nakazawa
Ken
K
Cellular and Molecular Pharmacology Section, Division of Pharmacology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya, Tokyo 158-8501, Japan. nakazawa@nihs.go.jp
Ohno
Yasuo
Y
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D015640:Ion Channel Gating / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008954:Models, Biological; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D018075:RNA, Complementary / Q000008:administration & dosage / Q000235:genetics; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000502:physiology*; D058476:Receptors, Purinergic P2X2; D013997:Time Factors; D014981:Xenopus
D018075:RNA, Complementary; D018048:Receptors, Purinergic P2; D058476:Receptors, Purinergic P2X2; D000255:Adenosine Triphosphate