Characteristics of pain receptors of cultured TG neurons. A, examples of currents recorded from rat and mouse TG neurons in culture (24 h) during application of α, β-meATP (10 μM, 2 s; upper row) and capsaicin (10 μM, 2 s for rat; 1 μM, 2 s for mouse; bottom row). B, log dose-response curves for rat (filled symbols; n = 9) and mouse (grey symbols; n = 12) neurons cultured for 24 h. Both potency and efficacy of α, β-meATP were similar for rat and mouse. C, distribution of values of the residual current (Iresidual) present at the end of an application of α, β-meATP (10 μM, 2 s) in rat and mouse neurons cultured for 24 h, expressed as a fraction of the peak current (Ipeak; n = 24 and 58 for rat and mouse, respectively). Inset shows an example of the mixed type of current recorded from a subset of rat TG neurons. Dashed line indicates the 5% arbitrary threshold above which currents were considered to be mixed.