A transporter for phenolamine uptake in the arthropod CNS

Abstract

Biogenic monoamines play central roles in the nervous control of physiological processes in both vertebrates and invertebrates, each using a suite of neurotransmitters tailored through evolution. Among the ancillary proteins necessary for the deployment of monoamine transmitters are membrane-bound transporters that enable the reuptake of synaptically released transmitters. Transporters responsible for monoamine uptake include a novel transporter discovered in a pest insect, the cabbage looper Trichoplusia ni, which has high affinity for the phenolamines octopamine and tyramine. Sequence analysis suggests that this transporter has no direct ortholog in the sequenced genomes of model invertebrates. We report here a preliminary investigation into the true extent of the distribution of this type of transporter using RT-PCR with a set of degenerate primers selective for monoamine transporters on cDNAs made from the nervous systems of a range of arthropods. PCR products encoding the N-terminal region of orthologs of this transporter were detected in a variety of insect orders, as well as in a crustacean, but were not found in representatives of either the Diptera or the Hymenoptera. Thus, although this transporter is widely expressed in invertebrates, there are various invertebrates that appear to have evolved alternate ways of recycling phenolamine neurotransmitters released at the nerve synapse.

Fast-Scan Cyclic Voltammetry (FSCV) Detection of Endogenous Octopamine in Drosophila melanogaster Ventral Nerve Cord

“…39 Octopamine has a similar structure to dopamine, and it has been suggested that the dopamine transporter could transport octopamine. 40 However, tests of Drosophila dopamine transporter (dDAT) expressed in MDCK cells found that octopamine was not a good substrate for dDAT.…”

Trace Amines and Their Receptors

“…Trace Amines and Their Receptors 571 (Roeder and Gewecke, 1989;McClung and Hirsh, 1998;Gallant et al, 2003;Donly and Caveney, 2005), with some evidence for species specificity in the transporters present (Roeder, 2005).…”

Drosophila melanogaster as a genetic model system to study neurotransmitter transporters

“…However, a plasma membrane OA transporter has not been identified in the fly. Surprisingly, a high affinity OA transporter has been identified in the cabbage looper Trichoplusia ni ( T. ni ) and several other insect species (Donly et al, 2007; Malutan et al, 2002), but is absent in Drosophila and other Diptera n species as well as bees ( Hymenoptera ) (Donly and Caveney, 2005). T. ni also express a high affinity DA transporter (Gallant et al, 2003).…”