Fig. 1. The pheromone response is characterized by six parameters. (A) A non-filtered (DC) response to a 50 ms stimulus of 1 µg bombykal (BAL). Action potentials are superimposed on the negative deflection of the transepithelial potential, the sensillar potential (SP) response. The maximal SP amplitude (SPA) is measured between the baseline before the response and the negative peak of the SP. The half-time of the rising phase (t_rise) is determined between the onset of the SP and the time the potential has reached 50% of the SPA (SPA). The second portion of the rising phase is described by an exponential fit of first order, using only the time constant (). For the analysis of all parameters describing the SP, the responses were low-pass filtered at 50 Hz. (B) The initial phase of the response at an enlarged time scale. The initial slope is determined by dividing SPA by t_rise. The AP latency is measured between the onset of the sensillar potential and the peak of the first action potential. (C) For the analysis of action potentials, the low-pass filtered response is subtracted from the original trace, yielding a straight baseline. The initial action potential frequency (AP frequency) is computed over the first five interspike intervals. (D) Pseudo-high-pass filtered (AC) response to a 50 ms stimulus of 10 µg BAL. The amplitudes of the large action potentials are reduced after strong BAL stimuli and regain their original amplitude in the course of several seconds (broken line). A spontaneous action potential of the non-BAL cell occurred before (filled arrow) the response. APs of the non-BAL cell can be separated from the BAL-APs by their lower and steady amplitude after stimulation with BAL. (E) Non-adapting stimulus-protocol: 50 ms long stimuli of 10 µg BAL per filter paper were applied with an interstimulus-interval (ISTI) of 5 min over a period of 180 min. 8bcGMP at 10 mmol l^-1 was applied by perfusion over the recording electrode with the beginning of the recording [modified after (Dolzer, 2003)].