Serotonin and Dopamine Have Opposite Effects on Phototaxis in Larvae of the Bryozoan Bugula neritina (original) (raw)
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Journal of Comparative Physiology A: Sensory, Neural, and Behavioral Physiology, 1997
The content of catecholamines and dihydroxyphenylalanine in larvae of the nudibranch Phestilla sibogae was analyzed by high-performance liquid chromatography with electrochemical detection. Dihydroxyphenylalanine, norepinephrine and dopamine were identi®ed in larvae of all ages examined (5 through 12 days post-fertilization). Dihydroxyphenylalanine could be accurately quanti®ed only in larvae of ages 8 through 12 days, when its average concentration increased from 0.62 to 6.71´10 A2 pmol lg protein A1 . Between ages 5 and 12 days dopamine rose from 0.081 to 0.616 pmol lg protein A1 , and norepinephrine from 0.45 to 2.17´10 A2 pmol lg protein A1 . Dihydroxyphenylalanine, dopamine and norepinephrine were also measured at dierent stages of metamorphic progress in 10-to 12-day larvae. Dihydroxyphenylalanine increased by a factor of 2.4 between the onset and completion of metamorphosis, but levels of dopamine and norepinephrine remained stable. One millimolar alpha-methyl-DL-m-tyrosine, an inhibitor of catecholamine synthesis, inhibited natural metamorphosis and depleted endogenous norepinephrine and especially dopamine, respectively, to 75% and 35% of control values. The existence of unexpectedly high levels of catecholamines in metamorphically competent larvae, and the association of catecholamine depletion with inhibition of metamorphosis, indicate that these compounds may participate in the control of gastropod development.
Archives of Insect Biochemistry and Physiology, 1999
were measured by HPLC using electrochemical detection. Larvae of two strains, wild-type (W) and nondiapause mutant (M), were maintained either under long-day (LD, inducing pupariation) or short-day (SD, inducing diapause in W-strain) photoperiods. The levels of DA ranged from 10 fmol/CNS (early 3rd instar larvae) to 60 fmol/CNS (150-day-old diapausing larvae); the range for 5-HT was from 10 fmol/CNS to 75 fmol/CNS in the same larvae. During the 3rd larval instar, which is the decisive stage for photoperiodic induction of diapause, no differences were found in DA developmental profiles between different strains or conditions. Some differences were found in 5-HT developmental profiles, but only after the end of sensitive stage, and were therefore regarded as insignificant for regulation of developmental mode. Similarly, no clear correlations between the developmental profiles of DA and 5-HT and the course of developmental changes during the maintenance and termination of a few-month-long larval diapause were observed. Furthermore, the DA and 5-HT levels in the CNS were pharmacologically manipulated by feeding the larvae with either precursors or enzyme inhibitors of DA and 5-HT biosynthesis. Although retardations of growth and development were observed, the treated larvae retained full capacity for the photoperiodic response, irrespective of the level of DA or 5-HT in their CNS. Larvae with their 5-HT depleted to trace levels survived and were capable of diapause induction, maintenance, and termination. Depletion of DA to trace levels resulted in 100% mortality. Collectively, the present study indicates that Abbreviations used: CNS = central nervous system; DA = dopamine; DD = continuous darkness; DOPA = L-3,4dihydroxyphenylalanine; EPI = epinephrine; HPLC-ECD = high pressure liquid chromatography-electrochemical detection; 5-HT = serotonin (5-hydroxytryptamine); 5-HTP = 5hydroxy-L-tryptophan; 3-IT = 3-iodo-L-tyrosine; JH = juvenile hormone; LD = long-day; LD20 = lethal dose 20%; M = mutant-strain; MEL = melatonin; NEPI = norepinephrine; OA = octopamine; p-CPA = p-chlorophenylalanine; PA = perchloric acid; PA50 = pupariation age 50%; PSS = physiological salt solution; PT50 = pupariation time 50%; PTTH = prothoracicotropic hormone; SD = short-day; W = wildstrain; WD-L = wing disc-length.
Dopamine and serotonin modulate the onset of metamorphosis in the ascidian Phallusia mammillata
Developmental Biology, 2005
Neurotransmitters play an important role in larval metamorphosis in different groups of marine invertebrates. In this work, the role of dopamine and serotonin during metamorphosis of the ascidian Phallusia mammillata larvae was examined. By immunofluorescence experiments, dopamine was localized in some neurons of the central nervous system and in the adhesive papillae of the larvae. Dopamine and serotonin signaling was
Systemic serotonin sulfate in opisthobranch mollusks
Journal of Neurochemistry, 2004
Serotonin (5-hydroxytryptamine, 5-HT) is a ubiquitous modulatory neurotransmitter with roles as a neurohormone and neurotransmitter. However, few studies have been performed characterizing this molecule and its related metabolites in circulating fluids. Here, we demonstrate native 5-HT sulfate, but much lower levels of 5-HT, in hemolymph of the marine mollusk Pleurobranchaea californica. The metabolite 5-HT sulfate forms from 5-HT uptake and metabolism in central ganglia of Aplysia californica and in the visceral nerve and eye of Pleurobranchaea, but not in hemolymph itself. In addition, 5-hydroxyindole acetic acid (5-HIAA), while not detected in hemolymph, forms in higher quantities than does 5-HT sulfate in the eye and visceral nerve, and c-glu-5-HT is also observed in this area but never in hemolymph. As systemic 5-HT sulfate appears not to originate from the optic region or from systemic 5-HT, 5-HT sulfate likely derives from the nervous system. Circulating 5-HT sulfate is at least 10-fold higher during the light portion of a 12 : 12-h light/dark cycle than during the dark portion (p < 0.0007), but there is no obvious trend for free systemic tryptophan (Trp) (p > 0.3) in Pleurobranchaea. 5-HT in mollusks is associated with general arousal state; thus, diurnal systemic changes in a 5-HT catabolite may reflect a regulatory role for indole catabolism in behavioral rhythms. Abbreviations used: CE, capillary electrophoresis; CNS, central nervous system; ENS, enteric nervous system; 5-HIAA, 5-hydroxyindole acetic acid; 5-HT, serotonin; 5-HTP, 5-hydroxytryptophan; MCC, metacerebral cell; PS, physiological saline; SEM, standard error of the mean; Trp, tryptophan.
Aquaculture, 2006
Catecholamines regulate several physiological processes in mollusks. Many pharmacological experiments have been conducted to determine the effects of adrenergic agonist and antagonist of catecholamine receptors on Meretrix meretrix metamorphosis. Results showed that adrenaline (AD) and noradrenaline (NA) had substantial effects (p b 0.05) on larval metamorphosis at concentrations ranging from 10 μM to 100 μM. 10 μM β-adrenergic receptor (AR) agonist isoproterenol showed the same inducement effect as that of NA and AD on metamorphosis, whereas the α-AR agonist phenylephrine had no significant effect at concentrations between 0.1 μM and 100 μM concentrations (p N 0.05). Furthermore, 1 μM β-AR antagonist propanolol, but not α-AR antagonist prazosin, depressed the larval metamorphosis induced by NA or AD. By immunocytochemistry, two cell bodies of β-adrenergic-like receptor, C/A1, C/A2, were observed in the cerebral/apical ganglion of competent larvae. In addition, there were other immunoreactive dots near C/A1 and C/A2. The results of pharmacology and immunocytochemistry suggests that βadrenergic-like receptor located in the larval CNS, might play a considerable role in the larval metamorphosis of M. meretrix by AD or NA.
Catecholamines Modulate Metamorphosis in the Opisthobranch Gastropod Phestilla sibogae
Biological Bulletin, 2000
Larvae of the nudibranch Phestilla sibogae are induced to metamorphose by a factor from their adult prey, the coral Porites compressa. Levels of endogenous catecholamines increase 6 to 9 days after fertilization, when larvae become competent for metamorphosis. Six-to nineday larvae, treated with the catecholamine precursor L-DOPA (0.01 mM for 0.5 h), were assayed for metamorphosis in response to coral inducer and for catecholamine content by high-performance liquid chromatography. L-DOPA treatment caused 20-to 50-fold increases in dopamine, with proportionally greater increases in younger larvae, so that L-DOPA-treated larvae of all ages contained similar levels of dopamine. A much smaller (about twofold) increase in norepinephrine occurred in all larvae. The treatment significantly potentiated the frequency of metamorphosis of 7-to 9-d larvae at low concentrations of inducer. In addition, L-DOPA treatment at 9 d increased aldehydeinduced fluorescence in cells that were also labeled in the controls, and revealed additional cells. However, all labeled cells were consistent with the locations of cells showing tyrosine-hydroxylase-like immunoreactivity. Catecholamines are likely to modulate metamorphosis in P. sibogae, but rising levels of catecholamines around the time of competence are insufficient alone to account for sensitivity to inducer in competent larvae.
Journal of Neurobiology, 1997
firmed in eggs using high-performance liquid chroma-ABSTRACT: The olfactory and accessory lobes tography with electrochemical detection. Morphometconstitute prominent histological structures within the ric analyses suggested that serotonin depletion larval and mature lobster deutocerebrum, and both dramatically slowed the growth of olfactory and accesare associated with a dense innervation from paired sory lobes, although glomeruli differentiated at the serotonergic nerve cells, the dorsal giant neurons normal time in both areas. The toxin exhibited a high (DGNs). During development, the cell bodies of the degree of specificity for serotonergic neurons and as-DGNs are the first central somata to express serotonin sociated target regions, and serotonin depletion per-(5-HT), and the onset of their 5-HT immunoreactivity sisted for at least 2 months following treatment. The coincides with the beginning of accessory lobe formagoal of future experiments is to determine which of the tion. In contrast, the olfactory lobe anlagen emerge cell types that innervate the olfactory and accessory much earlier and grow in the apparent absence of lobes are affected by toxin treatment, thereby resulting serotonin. The role of serotonergic input for the develin the retarded growth of these areas. ᭧ 1997 John opment of these brain structures was investigated in Wiley & Sons, Inc. J Neurobiol 33: 357-373, 1997 lobster embryos after serotonin had been depleted Keywords: 5,7-dihydroxytryptamine; serotonin; olfacpharmacologically with the neurotoxin 5,7-dihydroxytory lobes; accessory lobes; development tryptamine. A Ç90% reduction of serotonin was con-Correspondence to: B. S. Beltz shown that serotonin can inhibit (Haydon et al.,
Development, Growth and Differentiation, 2001
The neurotransmitter 5-hydroxytryptamine (5-HT, serotonin) plays an important role in a wide range of non-neural processes. Using immunofluorescence with an antiserotonin antibody, 5-HT was localized in the brain and in some neurons of the larval tail of Phallusia mammillata. To test the effect of 5-HT on development, we treated embryos with two different 5-HT receptor subtype antagonists. Treatment at the gastrula stage with 10 µM ondansetron, an antagonist of the 5-HT3 receptor, induced anterior truncation and a short tail. At 10 µM, ritanserin, a 5-HT2B receptor antagonist, induced larval phenotypes characterized by a roundish trunk region with flat papillae. The juveniles developed from these larvae had an abnormal cardiocirculatory system: their heart contractions were ineffective and their blood cells accumulated in the heart cavity. We conclude that an appropriate level of 5-HT is necessary for correct development and morphogenesis. Moreover, a different key role for multiple receptors in modulating the morphogenetic effects of 5-HT is suggested.
The Journal of Comparative Neurology, 1994
As a catecholamine, dopamine belongs to a class of molecules that have multiple transmitter and hormonal functions in vertebrate and invertebrate nervous systems. However, in the lobster, where many central neurons have been identified and the peripheral innervation pattern is well known, the distribution of dopamine-containing neurons has not been examined in detail. Therefore, immunocytochemical methods were used to identify neurons likely to contain dopamine and tyrosine hydroxylase in the central nervous system of the juvenile lobster Homarus gammarus. Approximately 100 neuronal somata stain for the catecholamine andlor its synthetic enzyme in the brain and ventral nerve cord. The systems of neurons labeled with dopamine and tyrosine hydroxylase antibodies have the following characteristics: 1) the two systems are nearly identical; 2) every segmental ganglion contains at least one pair of labeled neurons; 3) the positions and numbers of cell bodies labeled with each antiserum are similar in the various segmental ganglia; 4) six labeled neurons are anatomically identified; two interneurons from the brain project within the ventral cord to reach the last abdominal ganglion, two neurons from the commissural ganglia are presumably neurosecretory neurons, and two anterior unpaired medial abdominal neurons project to the hindgut muscles; and 5 ) no cell bodies are labeled in the stomatogastric ganglion, but fibers and terminals in the neuropil are stained. The remarkably small numbers of labeled neurons and the presence of very large labeled somata with far-reaching projections are distinctive features consistent with other modulatory aminergic systems in both vertebrates and invertebrates. o