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Ascidians are good monitors for assessing water quality, since they filter large volumes of water; however, little is known about how xenobiotics, including metals, can affect ascidian hemocytes. Metals can be either toxic or beneficial to health, inducing many different responses. The response mechanism depends on the class of metals to which organisms are exposed: essential, nonessential, and borderline. To analyze the influence of metals from different classes on the protective mechanisms of an ascidian, we investigated the production of nitric oxide (NO) after exposure to various concentrations of Mg, Mn and Pb over different time periods. We also determined the amounts of each metal in the hemocytes. Our results indicated that especially Pb could stimulate NO production. Although Pb induced the highest NO production, cell viability was not severely altered in all Pb concentrations and time periods. Ascidians might serve as biomonitor for Pb, since their vanadocytes accumulate Pb. [ABSTRACT FROM AUTHOR]

The effects of physical-therapy intervention on the motor function of upper limbs and the quality of life in patients with Parkinson's disease (PD) are not fully understood. We evaluated the effects of a progressive muscle-strengthening protocol for upper limbs on the functionality and quality of life. Patients were divided into two groups: Intervention (n = 6) and Control (n = 7). Assessment tools used were: Unified Parkinson's Disease Rating Scale (UPDRS), Parkinson's Disease Questionnaire, Nine-Hole Peg Test (9HPT), Test d'Évaluation des Membres Supérieurs de Personnes Âgées (TEMPA), 10-Repetition Maximum (10-RM) and handgrip dynamometer, which were applied pre- and post-intervention, with follow-up for one month after the last training session. Only, the Intervention group (post-intervention) showed significant statistical differences, with the following outcomes: UPDRS III (p = 0.042); 9HPT, right (p = 0.028) and left side (p = 0.028); TEMPA for total right side (p = 0.028), left side (p = 0.028) and total bilateral tasks (p = 0.028); TEMPA task 2 - open a jar and take a spoonful of coffee (p = 0.028), task 3 - pick up a pitcher and pour water into a glass for right (p = 0.046) and left side (p = 0.028), task 5 - write on an envelope and stick on a stamp (p = 0.028), and task 6 - shuffle and deal playing cards (p = 0.028). We observed significant statistical differences between groups (post-intervention) for TEMPA task 6 (p = 0.032), total right side (p = 0.032), and total bilateral tasks (p = 0.032). An increase in the maximum load in the post-intervention stage, based on the 10-RM test, was observed on the right (p = 0.003) and left (p = 0.007) sides. Our results showed an improvement in upper-limb functionality in PD patients submitted to progressive muscle-strength training, although not in quality of life. [ABSTRACT FROM AUTHOR]

Abstract To understand the mechanisms involved in organisms’ responses to toxicity from oil pollution, we studied the effect of acute exposure (24 h) to the marine water-soluble fraction of diesel oil (WFDO) on the ascidian Styela plicata. We evaluated the mortality and behavior by means of the siphon reflex, and the response of blood cells (hemocytes) contained in the pharynx, by means of the production of nitric oxide (NO) and reactive oxygen species (ROS), in addition to the activity of the antioxidant enzyme catalase (CAT). We also correlated oxidative stress with the activation of apoptotic pathways. No mortality occurred 24 h after the ascidians were exposed to 5% and 10% marine WFDO; however, the siphon reflex, a behavioral test based on the time that the animals took to close their siphons, increased. We also observed an inflammatory response, as estimated by the increase in the number of hemocytes in the pharynx. NO and ROS production and CAT activity were reduced, whereas caspase-3, a signaling molecule involved in apoptosis, was activated. This suggests that in ascidians acutely exposed to oil, another mechanism can occur in addition to oxidative stress. Another possibility is that WFDO may directly interact with cellular macromolecules and activate caspase-3, independently of generating oxidative stress. The results showed that components of diesel oil affected a marine organism, which showed reduced ROS production in the pharynx cells, including hemocytes, and activation of apoptotic pathways. Graphical abstract Image 1 Highlights • Water fraction diesel oil (WFDO) did not cause ascidian mortality. • WFDO altered the ascidian siphon reflex. • Nitric-oxide production was reduced in pharynx cells after acute WFDO exposure. • Reactive oxygen species were reduced in pharynx cells after acute WFDO exposure. • Catalase activity decreased after acute WFDO exposure. • Pharynx cells reacted to WFDO by activating apoptotic pathways. [ABSTRACT FROM AUTHOR]

The hemolymph of ascidians (Chordata-Tunicata) contains different types of hemocytes embedded in a liquid plasma. In the present study, heparin and a sulfated heteropolysaccharide were purified from the hemolymph of the ascidian Styelaplicata. The heteropolysaccharide occurs free in the plasma, is composed of glucose (-60%) and galactose (-40%), and is highly sulfated. Heparin, on the other hand, occurs in the hemocytes, and high performance liquid chromatography of the products formed by degradation with specific lyases revealed that it is composed mainly by the disaccharides z~UA(2SO4)-1--4-~-D-GlcN(SO4) (39.7%) and zIUA(2S04)- 1-~4-~-o-GlcN(SO4)(6SO4) (38.2%). Small amounts of the 3-0-sulfated disaccharides z~UA(2SO4)- 1-~.4-~3-o-GlcN(SO4)(3SO4) (9.8%) and ~UA(2SO4)-1--~4-I3-D- G1cN(S04)(3S04)(6504) (3.8%) were also detected. These 3-0- sulfated disaccharides were demonstrated to be essential for the binding of the hemocyte heparin to antithrombin III. Electron microscopy techniques were used to characterize the ultrastruc- ture of the hemocytes and to localize heparin and histamine in these cells. At least five cell types were recognized and classified as univacuolated and multivacuolated cells, amebocytes, hemo- blasts, and granulocytes. Immunocytochemistry showed that heparin and histamine co-localize in intracellular granules of only one type of hemocyte, the granulocyte. These results show for the first time that in ascidians, a sulfated galactoglucan cir- culates free in the plasma, and heparin occurs as an intracellular product of a circulating basophil-like cell. [ABSTRACT FROM AUTHOR]

Over the last two decades, ultraviolet radiation levels (UV), reaching the Earth''s surface, have been increasing at a rate of 1.5% per each 1% loss of the ozone layer. Moreover, artificial UV-sources have also proliferated and contributed to the rising UV-stress that many organisms have to face. To assess how the vertebrate retina responds to an exposure of short wavelength UV, we focused our attention on the rat retina, observing photoreceptor (containing outer and inner segments of rods and cones), inner plexiform, and ganglion cell layers by light and transmission electron microscopy using conventional and cytochemical techniques. We analyzed how cells of the layers in question responded to a 30 min exposure to UV-C and UV-B radiation with doses of 7200 and 590 J/cm2, respectively. The results show that there are significant changes in the nuclei and cytoplasmic organelles of the exposed retinae when compared with those of the unexposed controls. The changes include an increase in heterochromatin, distension of rough endoplasmic reticulum, mitochondrial disruptions, and increases in the number of myelin bodies. The recorded morphological changes, especially those of the ganglion cells, are suggestive of apoptotic processes and show that the exposure of vertebrate retina to wavelengths ranging from 254 to 312 nm can produce alterations that are likely to impact negatively on the retina''s proper functioning. [Copyright &y& Elsevier]

We carried out a qualitative review of the literature on the influence of forced or voluntary exercise in Parkinson's Disease (PD)-induced animals, to better understand neural mechanisms and the role of neurotrophic factors (NFs) involved in the improvement of motor behavior. A few studies indicated that forced or voluntary exercise may promote neuroprotection, through upregulation of NF expression, against toxicity of drugs that simulate PD. Forced training, such as treadmill exercise and forced-limb use, adopted in most studies, in addition to voluntary exercise on a running wheel are suitable methods for NFs upregulation. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) radiation can produce biological damage, leading the cell to apoptosis by the p53 pathway. This study evaluated some molecular markers of the apoptosis pathway induced by UVA, UVB and UVA+ UVB (Solar Simulator, SIM) in environmental doses, during five consecutive days of exposure, in the brain of the crab Ucides cordatus. We evaluated the central nervous system (CNS) by immunoblotting the content of proteins p53, p21, phosphorylated AKT, BDNF, GDNF, activated caspase-3 (C3) and phosphohistone H3 (PH3); and by immunohistochemical tests of the cells labeled for PH3 and C3. After the fifth day of exposure, UVB radiation and SIM increased the protein content of p53, increasing the content of AKT and, somehow, blocking p21, increasing the content of activated caspase-3, which led the cells to apoptosis. The signs of death affected the increase in neurotrophins, such as BDNF and GDNF, stimulating the apoptotic cascade of events. Immunohistochemical assays and immunoblotting showed that apoptosis was present in the brains of all UV groups, while the number of mitotic cells in the same groups decreased. In conclusion, environmental doses of UV can cause apoptosis by increasing p53 and decreasing p21, revealing an UV-damage pathway for U. cordatus . [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) radiation can produce biological damage, principally oxidative stress, by increasing the production of reactive oxygen species (ROS). This study evaluated biochemical impairments related to the oxidative stress induced by UVA, UVB and UVA + UVB (solar simulator-SIM) in environmental doses, during five consecutive days of exposure, in the brain and eyestalk of the crab Ucides cordatus . We evaluated these regions by sampling on the 1st, 3rd and 5th days of UV exposure for lipid peroxidation (LPO), antioxidant capacity against the peroxyl radical (ACAP), and the activities of catalase (CAT), glutathione peroxidase (GPX) and glutathione- S -transferase (GST). Immunohistochemical and immunoblotting assays were performed for anti-activated-caspase 3 in the brains. After the first day of exposure, LPO increased in the eyestalks and brains of the UV-exposed animals; ACAP, and CAT, GPX and GST activities also increased in the brains. On the third day, the LPO values in the eyestalk remained high in the UV-exposed groups, while ACAP decreased in the brain and eyestalk and CAT activity remained high in all irradiated groups in both regions. On the fifth day, LPO decreased in the eyestalk and brain of the UV-exposed groups. These results may have been a consequence of the antioxidant defense system (ADS) activity, since CAT activity was high in both regions, ACAP was high in the eyestalks of the SIM group, and GPX activity remained high in the eyestalks of the UVA and UVB groups. Immunohistochemical assays and immunoblotting showed that there was apoptosis in the brains of the UV-exposed crabs. In conclusion, environmental doses of UV can cause oxidative damage to the CNS cells, including apoptosis. [ABSTRACT FROM AUTHOR]

Abstract: We report the construction and characterization of a normalized cDNA library from the digestive gland of the marine bivalve Nodipecten nodosus, a commercially valuable tropical scallop. A total of 288 clones were sequenced, and 250 unique sequences were obtained. The cDNA library showed a small sequence redundancy (2.3%) and high numbers of recombinant (99.9%) and independent clones (2.0 × 106 cfu), indicating that the cDNA library generated in this study is a profitable resource for efficient gene discovery for N. nodosus. EST functional annotation by Gene Ontology term assignment revealed the identification of sequences potentially involved in aquaculture and ecotoxicology relevant processes such as apoptosis, growth, lipid metabolism, reproduction, development, response to stress and immunity. [Copyright &y& Elsevier]

Abstract: The first and main target-structure of ultraviolet (UV) radiation in animals is the body surface, including the skin and eyes. Here, we investigated cell damage in the visual system of the crab Neohelice granulata acclimated to constant light and exposed to UVA or UVB at 12:00h for 30min. The reactive oxygen species (ROS) production, antioxidant capacity against peroxyl radicals (ACAP), lipid peroxidation (LPO) damage, catalase (CAT) activity, and the melatonin immunohistochemical reactivity in the eyestalks were evaluated. The animals that received melatonin and were exposed to UVA and UVB radiation showed a decreased ROS concentration (p<0.05).The ACAP test showed a decrease (p<0.05) in their values when the animals received 2pmol/crab of melatonin (physiological dose) before the exposure to UVA radiation. The animals exposed to UVB radiation after receiving the same dose of melatonin showed an increase (p<0.05) in the ACAP test compared with the animals exposed to UVB radiation after receiving only crab physiological saline. The CAT activity increased (p<0.05) in the animals that received melatonin and were exposed to UVA and UVB radiation. Animals exposed to UVA and UVB displayed an increase (p<0.05) in the LPO levels, whereas animals treated with melatonin showed lower (p<0.05) LPO levels when irradiated. The results indicate that the specific oxidative parameters altered by UV radiation can be modulated by a physiological dose of melatonin. Moreover, the melatonin regularly produced by virtually all eyestalk cells suggests that it may function to modulate the noxious effects of radiation, at least in the crab N. granulata. [Copyright &y& Elsevier]

Abstract: The recent decrease of the stratospheric ozone has resulted in an increase of ultraviolet-B (UV-B) radiation reaching the Earth''s surface. In freshwater ecosystems with transparent water, UV-B rays easily penetrate and potentially cause harmful effects to organisms. In this study, embryos of the prawn Macrobrachium olfersi were used to evaluate the impact of UV-B rays in freshwater environments. We observed three groups of embryos: the first was to assess whether UV-B radiation produced morphological defects and/or biochemical impairments in the laboratory. The second was to check whether embryos with the same impairments as those observed in the laboratory were found in their environment, under natural solar radiation. The third group was the non-irradiated control. The embryos irradiated with 310mWcm−2 UV-B for 30min showed morphological alterations similar to those observed in embryos from the environmental control group. The most important effects of the UV-B radiation observed in M. olfersi embryos were morphological (1.2% of the total number of embryos from the environment and 2.8% of the total number of irradiated embryos), pigmentation changes in the eyes (78.0% of the total number of embryos from the environment and 98.9% of the total number of irradiated embryos), and disruption of the chromatophores (46.9% of the total number of embryos from the environment and 95.5% of the total number of irradiated embryos). We also observed an increase in egg volume, which was accompanied by a significant increase in water content in UV-B irradiated groups when compared with aquaria control embryos. In addition, a significant decrease in the mitotic index in eggs exposed to UV-B radiation was detected (0.17 for the embryos from the aquaria control, 0.10 for the embryos of the environmental control, and 0.04 for the irradiated groups). The low levels of NPSH and high levels of TBARS indicated that UV-B rays directly compromised the antioxidant function of the embryonic cells, leading to oxidative stress. Our combined morphological and biochemical analyses revealed important effects induced by UV-B on M. olfersi embryos, and the results suggest that the recent changes in global conditions may have injurious effects, at least on the embryos of freshwater prawns. [Copyright &y& Elsevier]

Abstract: Crustaceans are interesting models to study the effects of ultraviolet (UV) radiation, and many species may be used as biomarkers for aquatic contamination of UV radiation reaching the surface of the Earth. Here, we investigated cell damage in the visual system of crabs Neohelice granulata that were acclimated to either 12L:12D, constant light, or constant dark, and were exposed to UVA or UVB at 12:00h (noon). The production of reactive oxygen species (ROS), antioxidant capacity against peroxyl radicals (ACAP), lipid peroxidation (LPO) damage, catalase activity, and pigment dispersion in the eye were evaluated. No significant differences from the three groups of controls (animals acclimated to 12L:12D, or in constant light, or not exposed to UV radiation) were observed in animals acclimated to 12L:12D, however, crabs acclimated to constant light and exposed to UV radiation for 30min showed a significant increase in ROS concentration, catalase activity, and LPO damage, but a decrease in ACAP compared with the controls. Crabs acclimated to constant darkness and exposed to UV for 30min showed a significantly increased ROS concentration and LPO damage, but the ACAP and catalase activity did not differ from the controls (animals kept in the dark while the experimental group was being exposed to UV radiation). Pigment dispersion in the pigment cells of eyes of animals acclimated to constant light was also observed. The results indicate that UVA and UVB alter specific oxidative parameters; however, the cell damage is more evident in animals deviated from the normal dark/light rhythm. [Copyright &y& Elsevier]

Abstract: Melatonin is a biogenic amine, known from almost all phyla of living organisms. In vertebrates melatonin is produced rhythmically in the pinealocytes of the pineal gland, relaying information of the environmental light/dark cycle to the organism. With regard to crustaceans only a handful of studies exist that has attempted to identify the presence and possible daily variation of this substance. We set out to investigate whether in the crab Neohelice granulata melatonin was produced in the optic lobes of these animals and underwent rhythmic fluctuations related to the daily light/dark cycle. Our experimental animals were divided into three groups exposed to different photoperiods: normal photoperiod (12L:12D), constant dark (DD), and constant light (LL). The optic lobes were collected every 4 hours over a 24-h period for melatonin quantification by radioimmunoassay (RIA). N. granulata kept under 12 L:12D and DD conditions, showed daily melatonin variations with two peaks of abundance (p <0.05), one during the day and another, more extensive one, at night. Under LL-conditions no significant daily variations were noticeable (p >0.05). These results demonstrate the presence of a daily biphasic fall and rise of melatonin in the eyestalk of N. granulata and suggest that continuous exposure to light inhibits the production of melatonin synthesis. [Copyright &y& Elsevier]

Abstract: Sulfated glycosaminoglycans (GAGs) were isolated and characterized in thoracic muscle, fat body, whole digestive tract (stomach+intestine) and reproductive tract of adult male cockroaches, Periplaneta americana. Heparan sulfate (HS) was the predominant sulfated GAG species in the tissues analyzed, corresponding to more than 90% of the total sulfated GAG content. In both the thoracic muscle and fat body it was the only sulfated GAG species detected. We also determined the location of sulfated GAGs in most of these organs by histochemical analysis using 1,9-dimethylmethylene blue. In the thoracic muscle, sulfated GAG metachromatic staining was detected only in the connective tissue that surrounds the muscle bundles or fascicles. In the intestinal tract, metachromatic staining was observed in both epithelial and lining columnar cells. Only spermatozoa presented metachromatic material in the male reproductive tract. Since, HS corresponds to 90–100% of total sulfated GAGs in these tissues, the metachromatic staining specifically reflects the location of this particular sulfated GAG in these organs. In conclusion, the present study extends previous observations on the GAG composition in cockroaches providing new information on the tissue distribution and location of HS in several internal organs of adult males of the cockroach P. americana. [Copyright &y& Elsevier]

Abstract: The essential trace elements Cr and Mn are toxic at high concentrations and information about low concentration is insufficient in the literature. In polluted mangroves, the crab Ucides cordatus can represent a useful tool to assess information on the potential impact of trace elements like Cr and Mn on the environment, since this species is comestible and thus, commercially negotiated. Therefore, U. cordatus crabs were exposed in vivo to different concentrations of Cr and Mn solved in seawater and had their tissue distribution and subcellular deposits evaluated. The gill, hepatopancreas and muscle concentrations were determined by atomic absorption spectroscopy and the results showed that Cr and Mn presented the highest values in the gills rather than in the hepatopancreas and muscular tissue. Electron microscopy and analytical X-ray microanalysis revealed Cr precipitates on the gill surface, co-localized with epiphyte bacteria. In addition, since Cr and Mn did not equally accumulate in most of the tissues studied, glycemic rate of animals, which received injections of extracts of eyestalks of the contaminated crabs, were measured in order to evaluate whether the studied concentrations of Cr and Mn could produce any metabolic alteration. The results indicated that extracts of the eyestalks of crabs submitted to Cr and Mn salts and injected into normal crabs markedly influenced crustacean hyperglycemic hormone synthesis and/or release. The results are discussed with respect to sensitivity of the employed methods and the possible significance of the concentrations of Cr and Mn in the organisms. [Copyright &y& Elsevier]

Abstract: Glial fibrillary acidic protein (GFAP) is the main intermediate filament protein used as a marker for the identification of astrocytes in the central nervous system of vertebrates. Analogous filaments have been observed in the glial cells of many mollusks and annelids but not in crustaceans. The present study was carried out to identify by light microscopy immunohistochemistry, immunoelectronmicroscopy and immunoblotting, GFAP-like positive structures in the visual system of the crab Ucides cordatus as additional information to help detect and classify glial cells in crustaceans. Conventional electron microscopy, light microscopy of semithin sections and fluorescence light microscopy were also employed to characterize cells and tissues morphology. Our results indicated the presence of GFAP-like positive cell processes and cell bodies in the retina and adjoining optic lobe. The labeling pattern on the reactive profiles was continuous and very well defined, differing considerably from what has been previously reported in the central nervous system of some mollusks, where a diffuse spotted fluorescence pattern of labeling was observed. We suggest that this glial filament protein may be conserved in the evolution of the invertebrate nervous systems and that it may be used as a label for some types of glial cells in the crab. [Copyright &y& Elsevier]

We have previously characterized heparan sulfate (HS) as the major ovarian sulfated glycosaminoglycan (GAG) in females of Rhodnius prolixus, while chondroitin sulfate (CS) was the minor component. Using histochemical procedures we found that GAGs were concentrated in the ovarian tissue but not found inside the oocytes. Here, we extend our initial observations of GAG expression in R. prolixus by characterizing these molecules in other organs: the fat body, intestinal tract, and the reproductive tracts. Only HS and CS were found in the three organs analyzed, however CS was the major GAG species in these tissues. We also determined the compartmental distribution of GAGs in these organs by histochemical analysis using 1,9-dimethylmethylene blue, and evaluated the specific distribution of CS within both male and female reproductive tracts by immunohistochemistry using an anti-CS antibody. We also determined the GAG composition in eggs at days 0 and 6 of embryonic development. Only HS and CS were found in eggs at day 6, while no sulfated GAGs were detected at day 0. Our results demonstrate that HS and CS are the only sulfated GAG species expressed in the fat body and in the intestinal and reproductive tracts of Rhodnius male and female adults. Both sulfated GAGs were also identified in Rhodnius embryos. Altogether, these results show no qualitative differences in the sulfated GAG composition regarding tissue-specific or development-specific distribution. [Copyright &y& Elsevier]

• Spinal cord neurons are affected by striatal lesions produced by 6-hydroxydopamine. • Motor spinal cord neurons are influenced by treadmill training in a PD model. • Exercise increases the content of the enzyme tyrosine hydroxylase in the spinal cord. • Exercise increases the content of the neurotrophin CDNF in the spinal cord. Previous research advocates that exercise is a non-pharmacological therapy for Parkinson's disease (PD). However, few studies have investigated the effects of exercise on central nervous system structures other than the nigrostriatal pathway by using PD animal models. This study investigated the effects of exercise on tyrosine hydroxylase (TH)- and cerebral dopamine neurotrophic factor (CDNF)-containing spinal-cord neurons. Male Swiss mice were divided into 4 groups: sedentary control (SEDCONT), exercise control (EXERCONT), sedentary Parkinson (SEDPD), and exercise Parkinson (EXERPD). The PD groups were submitted to a surgical procedure for stereotaxic bilateral injection of 6-hydroxydopamine into the striatum. TH- and CDNF-containing spinal-cord neurons were evaluated in all groups, using immunohistochemistry and western-blotting. TH content in the ventral horn differed notably between the SEDPD and EXERPD groups. CDNF content was highest in the EXERPD group. SEDPD and EXERPD groups differed the most, as shown by immunohistochemistry and western-blotting. The EXERPD group showed the most intense labeling in immunohistochemistry compared to the SEDCONT and EXERCONT groups. Therefore, we showed here that exercise increased the content of both TH and CDNF in the spinal-cord neurons of a bilateral PD mouse model. We may assume that the spinal cord is affected in a PD model, and therefore this central nervous system region deserves more attention from researchers dealing with PD. [ABSTRACT FROM AUTHOR]

Neurotransmitters play key roles in regulating the homeostasis of organisms in stressful environments. Noradrenaline (NA) is the main neurotransmitter known to modulate immunological parameters, and is important in the crosstalk between the neuroendocrine and immune systems. In this study, using the ascidian Phallusia nigra , we analyzed the level of catecholamines (CA) in the plasma after mechanical stress, and the effect of NA on the oxidative stress (OS) displayed by immune cells. We measured the concentration of reactive oxygen species (ROS), and analyzed whether α- and/or β-adrenoreceptors (ARs) are involved in ROS modulation, lipid peroxidation (LPO), antioxidant capacity against peroxyl radicals (ACAP), and activity of the enzymes catalase (CAT) and glutathione S transferase (GST) in immune cells after incubation with different concentrations of NA, with or without zymosan (ZnA) challenge. The results showed that NA reduced ROS production, even in immune cells challenged with ZnA, and that this modulation occurred through α 1 -and β 1 -ARs. ACAP levels showed different responses, depending on whether immune cells were challenged or not with ZnA, and also depending on the NA concentration: 1.0 μM NA increased ACAP levels, but 10.0 μM reduced ACAP levels. NA enhanced the activity of CAT and GST in ZnA-challenged and non-challenged immune cells, while 1.0 and 10.0 μM NA effectively reduced LPO. Taken together, these results show that NA can protect cells from ROS damage, decreasing ROS production and LPO, and enhancing ACAP as well as the activity of CAT and GST. The approach used here with this model contributes to understanding the relationship between the neuroendocrine and immune systems, revealing new effects of NA on OS regulation in ascidians. Image 1062 • Besides acting as a neurotransmitter, noradrenaline (NA) modulates stress response in ascidians. • NA reduces the production of reactive oxygen species (ROS) in ascidian immune cells. • NA enhances antioxidant capacity against peroxyl radicals (ACAP). • NA increases catalase (CAT) and glutathione-S-transferase (GST) activity. • NA reduces lipid peroxidation (LPO) and protects immune cells from damage induced by ROS. [ABSTRACT FROM AUTHOR]