Distribution of tyrosine hydroxylase, dopamine, and serotonin in the central nervous system of amphioxus (Branchiostoma lanceolatum): Implications for the evolution of catecholamine systems in vertebrates

Abstract

To investigate the evolutionary transition that has shaped the catecholaminergic systems of vertebrates, the organization of catecholamine-synthesizing neurons and the nature of the catecholamines were examined in the central nervous system of adult amphioxus (Branchiostoma lanceolatum), a cephalochordate. We isolated a gene transcript encoding tyrosine hydroxylase (TH), the limiting enzyme of catecholamine biosynthesis, and studied its distribution together with that of dopamine and serotonin. Dopamine and TH are found in the same neurons of which they are three separate populations. Two are located in the anterior brain, the first being dorsal and lying in a row and the second being more posterior and lateral. A third population comprising a few dorsal commissural neurons was found in the posterior brain. The anterior dopaminergic cells innervate the ventral commissure of the cephalic vesicle, the hindbrain, and the spinal cord. A serotonin-containing cell group is located in the same plane as the second dopaminergic cell population but is more caudal, marking the probable transition between anterior brain and hindbrain, as deduced from gene expression patterns. The overall distribution of dopaminergic and serotoninergic systems is similar in amphioxus and vertebrate central nervous system and could be an ancestral character of chordates. As assayed by high-performance liquid chromatography and electrochemical detection, significant amounts of dopamine and octopamine, but not of noradrenaline, are present in amphioxus head. This finding is consistent with data obtained from most prostomian species. We conclude that the noradrenergic system is probably an innovation of vertebrates that appeared along with the neural crest and specific hindbrain nuclei.

Cerebrospinal fluid-derived Semaphorin3B orients neuroepithelial cell divisions in the apicobasal axis

“…In situ hybridization was carried out on 20-mm cryosections from gelatine/sucrose-embedded embryos, as described previously 54 .…”

Linoleic Acid Induces Calcium Signaling, Src Kinase Phosphorylation, and Neurotransmitter Release in Mouse CD36-positive Gustatory Cells

“…Determination of Monoamine Neurotransmitters by High Performance Liquid Chromatography (HPLC)-HPLC separation of monoamine neurotransmitters was performed as described elsewhere (8). Cultured CD36-negative and CD36-positive gustatory cells were incubated with LA, as mentioned in the legends, and at the end of incubation supernatant was removed and supplemented with equal volume of solution A (0.2 M perchloric acid, 2.7 mM EDTA, 5.26 mM sodium metabisulfite), then 100 pg of an internal standard (3,4-dihydroxybenzylamine hydrobromide) was added to each sample.…”

Semaphorin and neuropilin co-expression in motoneurons sets axon sensitivity to environmental semaphorin sources during motor axon pathfinding

“…Alternatively, 150 m vibratome sections were used for confocal analysis. In situ hybridization was performed as described previously (Moret et al, 2004). For immunostaining, cryosections, vibratome sections, embryos or explants were incubated overnight with the following antibodies diluted in 2% bovine serum albumin blocking solution: mouse anti-Myc (1/100; 9E10; Sigma, USA), goat anti-neuropilin 1 (1/50; R&D Systems, Minneapolis, USA), mouse anti-neurofilament 160 kDa (NF160kD; 1/100; RMO-270; Zymed, San Francisco, USA).…”