A short communication was published in November 2011 (Neurobiologie) based on a study from 2005 (Journal of Neuroscience).
In the blowfly Phormia regina, the authors investigated the effect on PER when flies are (pre-) exposed to odors. They found that feeding threshold to sugar increased in the presence of the repellent D-limonene and decreased in the presence of the attractant dithiothreitol (DTT). The levels of tyramine (TA) and octopamine (OA) were changed with feeding threshold in flies experienced by flavored food. Injection experiments with OA, TA, or their agonist and antagonist indicated that TA more directly mediates feeding threshold determination.
In the very recent communication the authors cloned tyrosine decarboxylase (Tdc) and tyrosine beta-hydroxylase (Tbh) cDNAs from Phormia regina (PregTdc and PregTbh), the enzymes catalyzing OA and TA. PregTdc and PregTbh had different expression patterns throughout the animal. Exposure to the repellent indeed changed the expression of the enzymes in antenna. Localization of immunoreactive material and receptors gave a hint at the underlying mechanism how aversive information is transferred.
Ishida, Y., & Ozaki, M. (2011). Aversive odorant causing appetite decrease downregulates tyrosine decarboxylase gene expression in the olfactory receptor neuron of the blowfly, Phormia regina Naturwissenschaften DOI: 10.1007/s00114-011-0865-1
Nisimura, T. (2005). Experiential Effects of Appetitive and Nonappetitive Odors on Feeding Behavior in the Blowfly, Phormia regina: A Putative Role for Tyramine in Appetite Regulation Journal of Neuroscience, 25 (33), 7507-7516 DOI: 10.1523/JNEUROSCI.1862-05.2005
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