Localized adaptation processes in olfactory sensilla of Saturniid moths

Abstract

Receptor potentials and nerve impulses were recorded extracellularly from the two olfactory cells innervating most sensilla trichodea on the antenna of male Antheraea polyphemus and Antheraea pemyi moths that respond to two key compounds, the sex pheromone components (E)-6, (Z)-11-hexadecadienyl acetate and (E)-6, (Z)-11-hexadecadienal. Stimulation with the key compound of one receptor cell auto-adapts this cell and also cross-adapts the other cell in the same sensillum but cross-adaptation is weaker than auto-adaptation. Local stimulation experiments demonstrate that sections of the olfactory receptor cell can be selectively adapted as monitored by the receptor potential response. The mechanism of impulse generation can adapt separately from the mechanism generating the receptor potential as indicated by an altered relationship between impulse response and receptor potential. These results demonstrate multiple and distributed adaptation processes in an olfactory bipolar neuron as studied in a time domain of seconds. Cross-adaptation may indicate extracellular alterations caused by excitation of one cell but could also be caused by direct inhibitory action of the stimulus compound.