“…Indeed this has always been the case in our isolated cell preparation: (i) probability of channel opening is describable by a second-order Boltzmann function with 10-90% activation of transducer current of between 150 and 300 nm Schulte et al, 2002; and these experiments, not illustrated), and (ii) saturation current versus voltage curve describable by a simple, one-energy barrier model, with zero reversal potential (Schulte et al, 2002; and these experiments, not illustrated). Our acceptance of data from a proportion of normal functioning channels is based on the still common assumption (e.g., Holton and Hudspeth, 1986;van Netten et al, 2003), based on single-channel data (Crawford et al, 1991;Géléoc et al, 1997;Ricci et al, 2003), that the whole-cell current is simply the sum of unitary currents from identical transducer channels.…”