Fig. 13.

Longitudinal response profile of an individual receptor-neuron innervating a sensillum trichodeum of a male antenna of Antheraea pernyi. Plotted are the amplitudes of the receptor-potentials reached after 100 ms (mV, lines), and the numbers of nerve impulses (dashed lines) fired within 100 ms. Local stimulation by 100-ms air puffs delivered from a glass capillary of 30 μm diameter (big circle) loaded with the main pheromone component (E,Z)-6,11-hexadecadienal. Two series of eight puffs (series 1, dots, and series 3, circles) released from the same capillary were applied with 30 s intervals between puffs, with the capillary positions moved from tip to base of the hair (technique of local stimulation see Kaissling 1995). After each series of local stimulations, series of four puffs from 7 mm wide glass cartridges loaded with increasing amounts of pheromone (μg/filter paper) were applied to the total antenna in order to determine dose-response curves (series 2, dots, and series 4, circles). Comparing the local responses with the dose–response curves it can be estimated that the sensitivity of the receptor-neuron at the hair base was only 5% of the one at the hair tip. The slightly weaker responses of the series 3 and 4 as compared with 1 and 2, respectively, might be ascribed to a fatigue of the stimulus sources or of the neuron. See discussion, “The shallow dose–response curve”