The invertebrate octopaminergic system affects many diverse processes and represents the counterpart to the vertebrate adrenergic/noradrenergic system with the classes of octopamine receptor (OAR) being homologous to those of vertebrate adrenergic receptors. However, there is still little information on the OARs present in different species, and the levels and distribution of these receptors throughout the body. cDNAs sharing high similarity with known insect OARs were cloned in three lepidopteran species: the cabbage looper, Trichoplusia nr, the true armyworm, Pseudaletia unipuncta; and the cabbage white, Pieris rapae. Seven major larval tissues and one adult tissue were examined in T. ni using quantitative real-time PCR to determine the relative expression levels of receptor transcripts. A subset of these tissues was also examined in P. unipuncta and P. rapae. All receptor transcripts were expressed in the nervous system of all three, however, the distribution of the different receptor types varied between species
