Amphioxus Serotonin

Cross reference:   Amphioxus Neurotransmitters       Serotonin References   

Searching for "amphioxus serotonin" yielded:                     
        PubMed = 8    
        Google = 156,000  

Phylogeny of enteric serotonergic neurons.  

It is concluded that enteric serotonergic neurons arose early in vertebrate evolution, possibly in an ancestral chordate resembling amphioxus, although probably not in more primitive prevertebrates, and that they are a general feature of the vertebrate bowel."  

Immunocytochemical Localization of Serotonin in Embryos, Larvae and Adults of the Lancelet, Branchiostoma Floridae
Only abstract available online.  I got the PDF from the library. 
Serotonin, as well as catecholamines, histamine, acetylcholine and γ -aminobutyric acid (GABA), are neurotransmitters that also act as endogenous growth signals in many organisms, ranging from unicellular to multicellular eukaryotes. The role of serotonin as an intracellular signal seems to be conserved during the evolution of eukaryotes." 
    "... neurotransmitters such as monoamines and acetylcholine regulate cell proliferation, differentiation and morphogenetic cell movements during cleavage and gastrulation in both invertebrates and vertebrates." 
    "Serotonin immunoreactivity was confined to the central nervous system (CNS) and digestive tract in adult specimens of B. floridae. A dorsolateral group of serotonin containing nerve cell bodies were found in the roof of the cerebral vesicle, posterior to the frontal eye complex and  anterior to the Joseph cells. At the same time, serotonergic neurons were observed mid-ventrally arranged in two parallel chains, nearby the central canal of the spinal cord." 
    "In adult lancelets, serotonin is also expressed in the most anterior region of the CNS, where clusters of serotonergic neurons are present in the roof of the cerebral vesicle." 
    "Recently, Anad`on et al. (1998)

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.  

    See:  Amphioxus Neurotransmitters 

Serotonin-containing cells in the nervous system and other tissue during ontogeny of a lancelet (Goog) 
Only abstract available online.  I got PDF from library. 
"The axons of the antero-lateral serotonergic neurons descend the nerve cord in lancelets. A similar supraspinal source of serotonin is supplied to the vertebrate spinal cord." 

A neurochemical map of the developing amphioxus nervous system.  

    See:  Amphioxus Neurotransmitters  .   

For information that is more directly focused on the Serotonin receptors, please see:
Serotonin Gate (5-HT3R)
Rodent 5-HT1R , Rodent 5-HT3R ,
Serotonin Metabotropic Receptor

For a fairly complete index to the serotonin references compiled on the
Boys without Fathers site, please see:  Serotonin References .