SINGLE-CHANNEL PROPERTIES OF ATP-GATED CATION CHANNELS (P2X RECEPTORS) HETEROLOGOUSLY EXPRESSED IN CHINESE-HAMSTER OVARY CELLS

The single channel properties of four P2X receptors heterologously exp ressed in Chinese hamster ovary cells were determined from outside-out patch recordings. P2X(1) and P2X(4) channels opened in brief flickery bursts with conductances of similar to 18 and 9 pS respectively. P2X( 2) receptors had a single channel conductance of similar to 21 pS. Ope nings of P2X(3) channels were too rapid to be reliably resolved. Appli cation of ATP to macro-patches expressing multiple P2X(2) or P2X(4) re ceptors evoked sustained currents, in contrast responses of P2X(1) or P2X(3) receptors desensitised during continued agonist application. Th ese data show that four different homomeric P2X receptors form ion cha nnels with distinct single channel properties.