Back to Search
Start Over
Kinetics of P2X7 Receptor-Operated Single Channels Currents
- Source :
- Biophysical Journal. 92:2377-2391
- Publication Year :
- 2007
- Publisher :
- Elsevier BV, 2007.
-
Abstract
- Human P2X7 receptors were expressed in Xenopus laevis oocytes and single channels were recorded using the patch-clamp technique in the outside-out configuration. ATP4- evoked two types of P2X7 receptor-mediated single channel currents characterized by short-lived and long-lived openings. The short- and long-lasting open states had mean open times of approximately 5 and approximately 20 ms and slope conductances near -60 mV of 9 and 13 pS, respectively. The open probabilities of the short and long openings were strongly [ATP4-]-dependent with EC50 values of approximately 0.3 mM and approximately 0.1 mM ATP4-, respectively. The channel kinetics did not change significantly during sustained P2X7 receptor activation for several minutes, as was also observed in recordings in the cell-attached patch-clamp configuration. Activation and deactivation of the short openings followed exponential time courses with time constants in the range of 20 ms, and displayed a shallow [ATP4-] dependence of the activation process. The kinetics of the short channel openings at negative membrane potentials fitted well to a linear C-C-C-O model with two ATP4- binding steps at equal binding sites with a dissociation constant Kd of 139 microM.
- Subjects :
- Kinetics
Biophysics
Analytical chemistry
Xenopus
Models, Biological
Xenopus laevis
Adenosine Triphosphate
Animals
Computer Simulation
Channels, Receptors, and Electrical Signaling
P2x7 receptor
Cells, Cultured
Membrane potential
biology
Receptors, Purinergic P2
Chemistry
Channel kinetics
Time constant
biology.organism_classification
Dissociation constant
Models, Chemical
Oocytes
Receptors, Purinergic P2X7
Ion Channel Gating
Communication channel
Subjects
Details
- ISSN :
- 00063495
- Volume :
- 92
- Database :
- OpenAIRE
- Journal :
- Biophysical Journal
- Accession number :
- edsair.doi.dedup.....bfcbee05fd7dfa59c738336ef047a020