Coelenterata Neuropeptides

Cross references:   Neuropeptides    Hormones   Evolution of Hormones    
Parazoa Hormones     Coelenterata Hormones   Hemichordate Hormones  
Protochordate Hormones

Gastrin/CCK in the nervous system of Coelenterates (PubMed)   

    Found in sensory nerve cells in the ectoderm of the mouth region of hydra and in nerve cells in the endoderm of all body regions of the sea anemone. 

Neurotensin-like immunoreactivity in the nervous system of Hydra (PubMed) 
Only the abstract is available online.  I haven't yet obtained the PDF. 
    "Neurotensin-like immunoreactivity is found in nerve fibers present in all body regions of hydra. The nerve fibers are especially numerous in the ectoderm at the bases of the tentacles and in the ectoderm at a site just above the foot." 

Substance P-like immunoreactivity in the nervous system of Hydra (PubMed)
Only the abstract is available online. I haven't yet obtained the PDF.
Using immunocytochemistry we find substance P-like material in nerve cells of hydra. These nerve cells are situated in the ectoderm of the basal disk and tentacles."  

Bombesin-like immunoreactivity in the nervous system of Hydra (PubMed)
Only the abstract is available online. I haven't yet obtained the PDF.  
With immunocytochemical methods, nerve cells have been detected in Hydra attenuata containing bombesin-like immunoreactivity. These nerve cells are located in ectoderm of all body regions of the animal and are especially abundant in basal disk and tentacles. ... The data show that bombesin-like peptides are among the phylogenetically oldest neuropeptides found so far."  

FMRFamide-like immunoreactivity in the nervous system of Hydra (PubMed)
Only the abstract is available online. I haven't yet obtained the PDF.  
FMRFamide-like immunoreactivity has been localized in different parts of the hydra nervous system. Immunoreactivity occurs in nerve perikarya and processes in the ectoderm of the lower peduncle region near the basal disk, in the ectoderm of the hypostome and in the ectoderm of the tentacles. ... The presence of FMRFamide-like material in coelenterates shows that this family of peptides is of great antiquity."  

Oxytocin/vasopressin-like immunoreactivity is present in the nervous system of Hydra     
Only the abstract is available online.  I obtained the PDF.   
Nerve cells have been found in hydra, which react with antisera to oxytocin, vasopressin and mesotocin. These nerve cells have a high density in the ectoderm of basal disk and tentacles and lower density in the ectoderm of peduncle, gastric region and hypostome. A very small number of nerve cells occur also in the endoderm of foot, gastric region and hypostome. By using a technique for simultaneous visualisation of nerve cells reacting with antisera to oxytocin and vasopressin, it can be shown that these nerve cells belong to a single population. In agreement with this, the staining of the nerve cells can be abolished by absorbing each antiserum with either oxytocin, vasopressin, [Lys8]vasopressin, vasotocin, mesotocin or isotocin, indicating that the antigenic determinant of hydra cross-reacts with those antibody subpopulations, which recognize common portions (sequence 1-2, 5-7, 9) of the oxytocin/vasopressin-like peptides. With radioimmunoassays that are specific for either oxytocin or vasopressin, only very low amounts of immunoreactivity were measured. In addition, the dilution curves in these assays were not parallel to the standards, indicating that the antigenic determinant of hydra is not oxytocin or vasopressin. The presence of oxytocin/vasopressin-like material in coelenterates, shows that this family of peptides is of great antiquity."  

FMRFamide immunoreactivity is generally occurring in the nervous system of coelenterates
Only the abstract is available online. I haven't yet obtained the PDF.  
Abundant FMRFamide immunoreactivity has been found in the nervous systems of all hydrozoan, anthozoan, scyphozoan and ctenophoran species that were looked upon. This general and abundant occurrence shows that FMRFamide-like material must play a crucial role in the functioning of primitive nervous systems."  

Properties of Catecholaminergic system in Coelenterates (PubMed)$=relatedarticles&logdbfrom=pubmed

Got PDF from library. 
    The catecholamine present shows similarities to noradrenalin but it is not identical with noradrenalin. Contrary to known vertebrate catecholaminergic systems, neither a reuptake system nor a degrading system is present in the coelenterate catecholaminergic nervous system. 

Coexistence of neuropeptides in hydra (PubMed)
Only the abstract is available online. I haven't yet obtained the PDF.  
Using a technique for simultaneous visualisation of two antigens in one section, oxytocin-like immunoreactivity has been found to coexist with bombesin-like immunoreactivity in neurons of the basal disk, gastric region and tentacles of hydra. Neurons with oxytocin-like immunoreactivity in peduncle and hypostome, on the other hand, have little or no bombesin-like material. Oxytocin-like immunoreactivity never coexists with FMRFamide-immunoreactivity. The neurons with oxytocin- and FMRFamide-like immunoreactivity, however, are often found to be closely intermingled. The results show that coexistence, as well as non-coexistence, of neuropeptides is a phylogenetically old principle."  

FMRFamide immunoreactivity in the nervous system of the medusa
Only the abstract is available online. I haven't yet obtained the PDF.  
Three different antisera to the molluscan neuropeptide Phe-Met-Arg-Phe-amide (FMRFamide) and two different antisera to the fragment RFamide were used to stain sections or whole mounts of the hydrozoan medusa Polyorchis penicillatus. All antisera stained the same neuronal structures. Strong immunoreactivity was found in neurons of the ectodermal nerve nets of the manubrium and tentacles, in neurons of the sensory epithelium, and in neurons at the periphery of the sphincter muscle. Strong immunoreactivity was also present in processes and perikarya of the whole outer nerve ring, in the ocellar nerves, and in nerve cells lying at the periphery of the ocellus. The inner nerve ring contained a moderate number of immunoreactive processes and perikarya, which were distinct from the swimming motor neurons.  
    In contrast to the situation in the hydrozoan polyp Hydra attenuata, no immunoreactivity was found with several antisera to oxytocin/vasopressin and bombesin/gastrin-releasing peptide. The morphology and location of most FMRFamide-immunoreactive neurons in Polyorchis coincides with two identified neuronal systems, which have been recently discovered from neurophysiological studies."      


Biogenic Amines in Coelenterates  (Wiki) 
Abstract only.  I got PDF from library.   
opamine is used as an intercellular messenger in hydrozoans. The colonian anthozoan Renilla, has beta-adrenergic mechanisms in monitoring bioluminescence and serotoninergic mechanisms in rhythmic contractions.
My comment:     
    Although I've filed this under 'endocrine', all of these receptors could be for neurotransmitters. 

Nervous systems of cnidarians

Abstract only. 
    "The primitive nervous system of cnidarians is strongly peptidergic: from a single sea anemone species Anthopleura elegantissima, we have now isolated 16 different novel neuropeptides. These peptides are biologically active and cause inhibitions or contractions in muscle preparations or isolated muscle cells from sea anemones.
    The various peptides are located in at least six distinct sets of neurons showing that sea anemone neurons have already specialized with respect to their peptide content. Using immuno-electronmicroscopy, we have found that the peptides are located in neuronal dense-cored vesicles associated with both synaptic and non-synaptic release sites.
    All these data indicate that evolutionarily "old" nervous systems use peptides as transmitters. We have also investigated the biosynthesis of the cnidarian neuropeptides. These neuropeptides are made as large precursor proteins which contain multiple (up to 36) copies of immature neuropeptides. Thus, the biosynthesis of neuropeptides in cnidarians is very efficient and comparable to that of higher invertebrates, such as molluscs and insects, and vertebrates.

Peptides in the nervous systems of cnidarians (PubMed)   
Abstract only.  I got very long PDF from library. 
Much the same information as above. 
"All peptides are localized in neurons of cnidarians and we have demonstrated the presence of some of the peptides in neurosecretory dense-cored vesicles. Most neuropeptides have an excitatory or inhibitory action on whole cnidarians, muscle preparations, and isolated muscle cells, suggesting that these peptides are neurotransmitters or neuromodulators.

Hydra peptide project 1993-2007 (PubMed)
Only the abstract is available online. I haven't yet obtained the PDF.  
A systematic screening of peptide signaling molecules (<5000 da) in Hydra magnipapillata (the Hydra Peptide Project) was launched in 1993 and at least the first phase of the project ended in 2007. From the project a number of interesting suggestions and results have been obtained.
    First, a simple metazoan-like Hydra appears to contain a few hundred peptide signaling molecules: half of them neuropeptides and the rest epitheliopeptides that are produced by epithelial cells.    
    Second, epitheliopeptides were identified for the first time in Hydra. Some exhibit morphogen-like activities, which accord with the notion that epithelial cells are primarily responsible for patterning in Hydra. A family of epitheliopeptides was involved in regulating neuron differentiation possibly through neuron-epithelial cell interaction.  
    Third, many novel neuropeptides were identified. Most of them act directly on muscle cells inducing contraction or relaxation. Some were involved in cell differentiation and morphogenesis.    
    During the course of this study, a number of important technical innovations (e.g. genetic manipulations in transgenic Hydra, high-throughput purification techniques, etc.) and expressed sequence tag (EST) and genome databases were introduced in Hydra research. They have already helped to identify and characterize novel peptides and will contribute even more to the Hydra Peptide Project in the near future."  

Neuropeptides and their functions in Hydra (PubMed)
Only the abstract is available online. I haven't yet obtained the PDF.  
In order to identify novel peptide signaling molecules involved in the regulation of developmental and physiological processes in the freshwater cnidarian, Hydra magnipapillata, we initiated a systematic peptide screening project, the Hydra Peptide Project.  
    In the project, twelve neuropeptides were identified so far. The LWamide family is composed of seven members, which share a GLWamide motif at their C-termini. All the peptides have an ability to induce metamorphosis of Hydractinia serrata planula larvae into polyps. In Hydra, LWamides induce detachment of the bud from a parental polyp.  
    A neuropeptide, Hym-355, enhances neuronal differentiation by inducing the multipotent interstitial stem cells to enter the neuron differentiation pathway.  
    A myoactive neutopeptide, Hym-176, specifically and reversibly induces contraction of the ectodermal muscle of the body column, in particularly in the peduncle region of epithelial Hydra that totally lack nerve cells.  
    Two members of a novel neuropeptide family (FRamides) were contained in the same precursor. However, they have opposite myoactive functions in epithelial hydra.  
    From these results, it seems fair to say reasonable to conclude that the so-called 'primitive' nervous system of Hydra is in reality more complex than generally believed."  
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