Living without DAT: Loss and compensation of the dopamine transporter gene in sauropsids (birds and reptiles)

The dopamine transporter (DAT) is a major regulator of synaptic dopamine (DA) availability. It plays key roles in motor control and motor learning, memory formation, and reward-seeking behavior, is a major target of cocaine and methamphetamines, and has been assumed to be conserved among vertebrates...

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Bibliographic Details
Authors: Lovell, P. V., Kasimi, B., Carleton, J., Velho, Tarciso André Ferreira, Mello, C. V.
Format: article
Status:Published version
Publication Date:2015
Country:Brasil
Institution:Universidade Federal do Rio Grande do Norte (UFRN)
Repository:Repositório Institucional da UFRN
Language:English
OAI Identifier:oai:repositorio.ufrn.br:123456789/23137
Online Access:https://repositorio.ufrn.br/jspui/handle/123456789/23137
Access Level:Open access
Keyword:dopamine transporter
synaptic dopamine
noradrenaline transporter
dopaminergic cells
Description
Summary:The dopamine transporter (DAT) is a major regulator of synaptic dopamine (DA) availability. It plays key roles in motor control and motor learning, memory formation, and reward-seeking behavior, is a major target of cocaine and methamphetamines, and has been assumed to be conserved among vertebrates. We have found, however, that birds, crocodiles, and lizards lack the DAT gene. We also found that the unprecedented loss of this important gene is compensated for by the expression of the noradrenaline transporter (NAT) gene, and not the serotonin transporter genes, in dopaminergic cells, which explains the peculiar pharmacology of the DA reuptake activity previously noted in bird striatum. This unexpected pattern contrasts with that of ancestral vertebrates (e.g. fish) and mammals, where the NAT gene is selectively expressed in noradrenergic cells. DA circuits in birds/reptiles and mammals thus operate with an analogous reuptake mechanism exerted by different genes, bringing new insights into gene expression regulation in dopaminergic cells and the evolution of a key molecular player in reward and addiction pathways.