Fig. 1.

Expression of P2X7 mRNA transcripts and functional assays of P2X receptor expression. (A) RT-PCR was performed for P2X7 variants using the primers described in Table 1. Amplification products of the expected size were detected where E represents mouse embryonic stem cells, M represents J774.2 mouse macrophages and -T is the no template control. (B) Whole cell patch clamp recordings from undifferentiated mouse ES cells at the holding potential of − 60 mV. Histogram summarises the mean peak currents normalised to membrane capacitance detected at the ATP concentrations given. (C) Membrane permeabilisation measured by the uptake of ethidium and corresponding increase in fluorescent signal (544 nm excitation; 590 nm emission). An example kinetic trace of ethidium measurements from mouse ES cells with a saline vehicle (○) versus the addition of 1 mM ATP (●). (D) Concentration response relationship for ATP versus the rate of ethidium influx normalised to 1 mM ATP responses (n = 5) as described in methods. Data are plotted as the mean ± SEM.