Electroantennography (EAG) is a method for recording electrical potentials from insect antennae. These potentials provide information on the olfactory perception of insects. The EAG-technique records the 'slow' changes of potential that are caused by the superposition of simultaneous membrane depolarisations of numerous receptor cells. The EAG-signal of an insect antenna responding to a short (< 0.5 s) odor stimulation will typically persist for several seconds.
Potentials are measured in the extracellular hemolymph within the antenna. In order to achieve this, one electrode has to be connected to the distal end of the antenna. A second electrode connects to the other end of the antenna or the head of the insect. Potentials are amplified with a high-impedance amplifier (typically by a factor of 100).
In connection with a gas chromatographic separation an insect antenna can be used as an "electroantennographic detector" (EAD).
Multidimensional EAG, a novel method for utilizing the selectivity of insect antennae for the analysis of complex mixtures of odorants, is based on the presence of different populations of group specific olfactory receptor molecules within one antenna. Different qualities of odours are represented as orthogonal vectors, and their mixtures as sums of vectors, in a multidimensional "odor space". Design and test of this method is accomplished with antennae of the well-known and readily available Colorado potato beetle and a special biosensor-system. Possibilities and limits of the multidimensional EAG approach in odour qualification and quantification are examined by the analysis of artificial odorant mixtures and of natural odor samples.
In cooperation with:
Prof. Dr. Uwe T. Koch, Tierphysiologie, Universität Kaiserslautern