vglut2 and gad expression reveal distinct patterns of dual GABAergic versus glutamatergic cotransmitter phenotypes of dopaminergic and noradrenergic neurons in the zebrafish brain.
Bottom Line: Our results show that most dopaminergic neurons also express GABAergic markers, including the dopaminergic groups of the olfactory bulb (homologous to mammalian A16) and the subpallium, the hypothalamic groups (A12, A14), the prethalamic zona incerta group (A13), the preoptic groups (A15), and the pretectal group.All together, our results demonstrate that all catecholaminergic groups in zebrafish are either GABAergic or glutamatergic.We compare our results with those that have been described for mammalian systems, discuss the phenomenon of transmitter dualism in the context of developmental specification of GABAergic and glutamatergic regions in the brain, and put this phenomenon in an evolutionary perspective.
Affiliation: Developmental Biology, Institute of Biology I, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany.Show MeSH
Mentions: In the medulla oblongata (Fig. 7B), whereas no overlap was observed between TH and gad (Fig. 7C), we clearly detected coexpression of TH with vglut2 in most noradrenergic neurons (Fig. 7D–D3). A minor number of cells, however, were free of vglut2-expression. However, due to the poor quality of the sections obtained for the posterior hindbrain, the data collected for the noradrenergic group of the medulla oblongata were not complete, and we were not able to determine whether those few vglut2-free cells were GABAergic instead.
Affiliation: Developmental Biology, Institute of Biology I, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany.