Figure 5. Oscillatory changes in receptor current and fluo-3 fluorescence in response to prolonged odour stimulation.

A, response of an isolated olfactory receptor cell to a 30 s exposure to 30 μm cineole in Ringer solution. Upper panel, suction pipette current; lower panel, photomultiplier (PMT) current evoked by fluo-3 fluorescence. Period of receptor current oscillation, 2.8 s. B, recordings from the same cell stimulated in a solution in which Na⁺ was replaced with choline. Period of receptor current oscillation, 4.3 s. The junction current accompanying the solution change from Ringer to low-Na⁺, choline solution has not been subtracted; the minimum level of suction pipette current following the initial peak at the onset of stimulation was assigned to zero current. Topmost traces in A and B, laser and solution monitors, denoted by the continuous trace and filled bar respectively.