P2X2 / P2X3 - "P2X2/3 receptors recorded on Nanion's Patchliner"
Patchliner application note: (0.4 MB)
Cells were kindly provided by Evotec.
P2X receptors are ligand-gated ion channels that open in response to extracellular ATP. They are permeable to small monovalent cations, some having significant divalent or anion permeability. P2X receptors are found on many cell types including smooth muscle cells, sensory neurones, epithelia, bone and leukocytes. A role for P2X receptors has been suggested in transmission of thermal stimuli4, chemosensory signalling and taste. To date 7 P2X receptor genes have been cloned and studied in heterologous expression systems. Functional receptors are oligomeric, usually containing 3 or 6 subunits, which can be homomeric or heteromeric. The P2X2 and P2X3 receptors can function either as homomers or as P2X2/ P2X3 heteromers. When expressed together, a mixture of P2X2 and P2X3 homomers as well we P2X2/3 heteromers are likely to exist, which may be distinguished through their biophysical and pharmacological properties. Here we present data collected on a 4- or 8-channel Patchliner showing the potential use of the Patchliner to record P2X2/3 currents activated by ATP. ATP activated P2X2/3 receptors in a concentrationdependent manner with an EC50 similar to those reported in the literature for a mixture of homomeric and heteromeric P2X2 and P2X2/3 receptors. The currents desensitized slowly confirming that they are mediated by P2X2/P2X2/3 receptors rather than P2X3 receptors which desensitize very fast and recover slowly from desensitization. P2X2/P2X2/3 receptors could be repetitively activated by ATP and blocked by suramin with an IC50 in good agreement with the literature.