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1.
J Clin Med ; 13(8)2024 Apr 12.
Article in English | MEDLINE | ID: mdl-38673519

ABSTRACT

Identifying biomarkers linked to pancreatic ductal adenocarcinoma (PDAC) and chronic pancreatitis (CP) is crucial for early detection, treatment, and prevention. Methods: Association analyses of 10 serological biomarkers involved in cell signalling (IFN-γ, IL-6, IL-8, IL-10), oxidative stress (superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzyme activities, total glutathione (GSH), malondialdehyde (MDA) levels), and intestinal permeability proteins (zonulin, I-FABP2) were conducted across PDAC (n = 12), CP (n = 21) and control subjects (n = 23). A Mendelian randomisation (MR) approach was used to assess causality of the identified significant associations in two large genetic cohorts (FinnGen and UK Biobank). Results: Observational results showed a downregulation of SOD and GPx antioxidant enzyme activities in PDAC and CP patients, respectively, and higher MDA levels in CP patients. Logistic regression models revealed significant associations between CP and SOD activity (OR = 0.21, 95% CI [0.05, 0.89], per SD), GPx activity (OR = 0.28, 95% CI [0.10, 0.79], per SD), and MDA levels (OR = 2.05, 95% CI [1.36, 3.08], per SD). MR analyses, however, did not support causality. Conclusions: These findings would not support oxidative stress-related biomarkers as potential targets for pancreatic diseases prevention. Yet, further research is encouraged to assess their viability as non-invasive tools for early diagnosis, particularly in pre-diagnostic CP populations.

2.
PLoS One ; 19(2): e0297836, 2024.
Article in English | MEDLINE | ID: mdl-38363772

ABSTRACT

Gut microbiota may be involved in the presence of irritable bowel syndrome (IBS)-like symptomatology in ulcerative colitis (UC) patients in remission. Bread is an important source of dietary fiber, and a potential prebiotic. To assess the effect of a bread baked using traditional elaboration, in comparison with using modern elaboration procedures, in changing the gut microbiota and relieving IBS-like symptoms in patients with quiescent ulcerative colitis. Thirty-one UC patients in remission with IBS-like symptoms were randomly assigned to a dietary intervention with 200 g/d of either treatment or control bread for 8 weeks. Clinical symptomatology was tested using questionnaires and inflammatory parameters. Changes in fecal microbiota composition were assessed by high-throughput sequencing of the 16S rRNA gene. A decrease in IBS-like symptomatology was observed after both the treatment and control bread interventions as reductions in IBS-Symptom Severity Score values (p-value < 0.001) and presence of abdominal pain (p-value < 0.001). The treatment bread suggestively reduced the Firmicutes/Bacteroidetes ratio (p-value = 0.058). In addition, the Firmicutes/Bacteroidetes ratio seemed to be associated with improving IBS-like symptoms as suggested by a slight decrease in patient without abdominal pain (p-value = 0.059). No statistically significant differential abundances were found at any taxonomic level. The intake of a bread baked using traditional elaboration decreased the Firmicutes/Bacteroidetes ratio, which seemed to be associated with improving IBS-like symptoms in quiescent ulcerative colitis patients. These findings suggest that the traditional bread elaboration has a potential prebiotic effect improving gut health (ClinicalTrials.gov ID number of study: NCT05656391).


Subject(s)
Colitis, Ulcerative , Irritable Bowel Syndrome , Humans , Irritable Bowel Syndrome/diagnosis , Colitis, Ulcerative/complications , Pilot Projects , Dysbiosis/complications , RNA, Ribosomal, 16S , Bread , Diet , Abdominal Pain
3.
Article in English | MEDLINE | ID: mdl-37002418

ABSTRACT

Living organisms display molecular, physiological and behavioral rhythms synchronized with natural environmental cycles. Understanding the interaction between environment, physiology and behavior requires taking into account the complexity of natural habitats and the diversity of behavioral and physiological adaptations. Brachyhypopomus gauderio is characterized by the emission of electric organ discharges (EOD), with a very stable rate modulated by social and environmental cues. The nocturnal arousal in B. gauderio coincides with a melatonin-dependent EOD rate increase. Here, we first show a daily cycle in both the EOD basal rate (EOD-BR) and EOD-BR variability of B. gauderio in nature. We approached the understanding of the role of melatonin in this natural behavior through both behavioral pharmacology and in vitro assays. We report, for the first time in gymnotiformes, a direct effect of melatonin on the pacemaker nucleus (PN) in in vitro preparation. Melatonin treatment lowered EOD-BR in freely moving fish and PN basal rate, while increasing the variability of both. These results show that melatonin plays a key role in modulating the electric behavior of B. gauderio through its effect on rate and variability, both of which must be under a tight temporal regulation to prepare the animal for the challenging nocturnal environment.


Subject(s)
Electric Fish , Gymnotiformes , Melatonin , Animals , Electric Fish/physiology , Melatonin/pharmacology , Gymnotiformes/physiology , Electric Organ/physiology , Behavior, Animal/physiology
4.
Horm Behav ; 159: 105475, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38154435

ABSTRACT

The South American weakly electric fish, Gymnotus omarorum, displays territorial aggression year-round in both sexes. To examine the role of rapid androgen modulation in non-breeding aggression, we administered acetate cyproterone (CPA), a potent inhibitor of androgen receptors, to both male and females, just before staged agonistic interactions. Wild-caught fish were injected with CPA and, 30 min later, paired in intrasexual dyads. We then recorded the agonistic behavior which encompasses both locomotor displays and emission of social electric signals. We found that CPA had no discernible impact on the levels of aggression or the motivation to engage in aggressive behavior for either sex. However, CPA specifically decreased the expression of social electric signals in both males and female dyads. The effect was status-dependent as it only affected subordinate electrocommunication behavior, the emission of brief interruptions in their electric signaling ("offs"). This study is the first demonstration of a direct and rapid androgen effect mediated via androgen receptors on non-breeding aggression. Elucidating the mechanisms involved in non-breeding aggression in this teleost model allows us to better understand potentially conserved or convergent neuroendocrine mechanisms underlying aggression in vertebrates.


Subject(s)
Electric Fish , Gymnotiformes , Animals , Female , Male , Aggression , Receptors, Androgen , Agonistic Behavior , Androgens/pharmacology
5.
PLoS One ; 18(10): e0289461, 2023.
Article in English | MEDLINE | ID: mdl-37816021

ABSTRACT

Steroids play a crucial role in modulating brain and behavior. While traditionally it is thought that the brain is a target of sex steroids produced in endocrine glands (e.g. gonads), the brain itself produces steroids, known as neurosteroids. Neurosteroids can be produced in regions involved in the regulation of social behaviors and may act locally to regulate social behaviors, such as reproduction and aggression. Our model species, the weakly electric fish Gymnotus omarorum, displays non-breeding aggression in both sexes. This is a valuable natural behavior to understand neuroendocrine mechanisms that differ from those underlying breeding aggression. In the non-breeding season, circulating sex steroid levels are low, which facilitates the study of neurosteroids. Here, for the first time in a teleost fish, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify a panel of 8 steroids in both plasma and brain to characterize steroid profiles in wild non-breeding adult males and females. We show that: 1) systemic steroid levels in the non-breeding season are similar in both sexes, although only males have detectable circulating 11-ketotestosterone, 2) brain steroid levels are sexually dimorphic, as females display higher levels of androstenedione, testosterone and estrone, and only males had detectable 11-ketotestosterone, 3) systemic androgens such as androstenedione and testosterone in the non-breeding season are potential precursors for neuroestrogen synthesis, and 4) estrogens, which play a key role in non-breeding aggression, are detectable in the brain (but not the plasma) in both sexes. These data are consistent with previous studies of G. omarorum that show non-breeding aggression is dependent on estrogen signaling, as has also been shown in bird and mammal models. Overall, our results provide a foundation for understanding the role of neurosteroids, the interplay between central and peripheral steroids and potential sex differences in the regulation of social behaviors.


Subject(s)
Electric Fish , Neurosteroids , Animals , Female , Male , Androstenedione , Chromatography, Liquid , Tandem Mass Spectrometry , Aggression/physiology , Gonadal Steroid Hormones , Testosterone , Steroids , Estrogens , Brain , Seasons , Mammals
7.
Opt Express ; 31(8): 12261-12279, 2023 Apr 10.
Article in English | MEDLINE | ID: mdl-37157389

ABSTRACT

Hyperspectral (HS) imaging (HSI) expands the number of channels captured within the electromagnetic spectrum with respect to regular imaging. Thus, microscopic HSI can improve cancer diagnosis by automatic classification of cells. However, homogeneous focus is difficult to achieve in such images, being the aim of this work to automatically quantify their focus for further image correction. A HS image database for focus assessment was captured. Subjective scores of image focus were obtained from 24 subjects and then correlated to state-of-the-art methods. Maximum Local Variation, Fast Image Sharpness block-based Method and Local Phase Coherence algorithms provided the best correlation results. With respect to execution time, LPC was the fastest.

8.
Sensors (Basel) ; 23(4)2023 Feb 07.
Article in English | MEDLINE | ID: mdl-36850461

ABSTRACT

Hyperspectral Imaging (HSI) is increasingly adopted in medical applications for the usefulness of understanding the spectral signature of specific organic and non-organic elements. The acquisition of such images is a complex task, and the commercial sensors that can measure such images is scarce down to the point that some of them have limited spatial resolution in the bands of interest. This work proposes an approach to enhance the spatial resolution of hyperspectral histology samples using super-resolution. As the data volume associated to HSI has always been an inconvenience for the image processing in practical terms, this work proposes a relatively low computationally intensive algorithm. Using multiple images of the same scene taken in a controlled environment (hyperspectral microscopic system) with sub-pixel shifts between them, the proposed algorithm can effectively enhance the spatial resolution of the sensor while maintaining the spectral signature of the pixels, competing in performance with other state-of-the-art super-resolution techniques, and paving the way towards its use in real-time applications.


Subject(s)
Algorithms , Environment, Controlled , Histological Techniques , Hyperspectral Imaging , Image Processing, Computer-Assisted
9.
Rev Esp Enferm Dig ; 115(9): 523-524, 2023 09.
Article in English | MEDLINE | ID: mdl-36454092

ABSTRACT

Endoscopic retrograde cholangiopancreatography (ERCP) placement of biliary stents is the procedure of choice for bile duct strictures. Complications of endoscopic retrograde cholangiopancreatography have a low incidence. Hepatic subcapsular hematoma is uncommon but potentially serious. It is caused by laceration of the bile duct with guidewire or biliary traction during the procedure. Initial management is conservative with supportive measures. In case of hemodynamic instability or superinfection, embolization of the affected branch or even surgery could be performed.


Subject(s)
Biliary Tract Surgical Procedures , Liver Diseases , Humans , Cholangiopancreatography, Endoscopic Retrograde/adverse effects , Liver Diseases/diagnostic imaging , Liver Diseases/etiology , Bile Ducts , Biliary Tract Surgical Procedures/adverse effects , Hematoma/diagnostic imaging , Hematoma/etiology , Hematoma/therapy , Gastrointestinal Hemorrhage/complications , Stents/adverse effects
10.
Rev. salud pública ; 24(2)mar.-abr. 2022.
Article in Spanish | LILACS-Express | LILACS | ID: biblio-1536721

ABSTRACT

Objetivo Identificar y caracterizar el virus SARS-CoV-2 en una leona africana (Panthera leo), hembra, de edad avanzada, que presentó por varios meses signos relacionados con enfermedad respiratoria atípica. Métodos Se tomaron muestras de hisopados nasales 23 días después de haber reportado secreción nasal inicial. Se realizó la detección del virus SARS-Cov2 mediante RT-qPCR y posteriormente se caracterizó el genoma completo mediante secuencia Illumina. Resultados Desde el punto de vista clínico, los resultados encontrados en las muestras de sangre no mostraron cambios evidentes que se pudieran relacionar con el virus o con todos los signos descritos desde el inicio del caso. Para la secuenciación genómica los análisis mostraron una alineación múltiple comparativa entre los tres genomas (muestra Leona, FIP u NC_045512 [Wu han]) por medio de Mauve, centrado en los genes Spike, E y M (archivo complementario, parte B). Se logró identificar 5 segmentos muy similares entre Leona y NC_045512 (Wuhan). Conclusiones Es necesario adelantar más investigaciones para estandarizar el diagnóstico de esta patología en los animales. Así mismo, se requieren estudios genómicos en estas especies. Además, se evidenció con la revisión del estado de la cuestión que existen muchos vacíos del conocimiento en la implicación zoonótica de la pandemia y en el conocimiento de este virus en animales domésticos y silvestres, lo que supone un reto importante para las investigaciones de aquí en adelante.


Objective To identify and characterize the SARS-CoV-2 virus in an elderly African lioness (Panthera leo) that presented signs related to atypical respiratory disease for several months. Methods Nasal swab samples were taken 23 days after infection. have reported initial nasal discharge. Results The SARS-Cov2 virus was detected by RT-qPCR and the complete genome was subsequently characterized by Illumina sequencing. The results found in the blood samples did not show obvious changes that could be related to the virus or to the signs described from the beginning of the case. For genomic sequencing the analyzes showed a comparative multiple alignment between the three genomes (sample Leona, FIP or NC_045512 (Wu han)) by means of Mauve, focusing on the Spike, E and M genes (Supplementary file, part B); 5 very similar segments between Leona and NC_045512 (Wuhan) was identified. Conclusions It is necessary to carry out more research to standardize the diagnosis of this pathology in animals and guarantee access to it. Also, genomic studies in these species. Additionally, it was evidenced with the literature review that there are many knowledge gaps in the zoonotic implication of the Pandemic and in the knowledge of this virus in domestic and wild animals, which represents an important challenge for research from now on.

11.
ACS Appl Mater Interfaces ; 14(3): 4022-4034, 2022 Jan 26.
Article in English | MEDLINE | ID: mdl-35019264

ABSTRACT

A series of hybrid electrolytes composed of diglyme and ionic liquids (ILs) have been investigated for Na-O2 batteries, as a strategy to control the growth and purity of the discharge products during battery operation. The dependence of chemical composition of the ILs on the size, purity, and distribution of the discharge products has been evaluated using a wide range of experimental and spectroscopic techniques. The morphology and composition of the discharge products found in the Na-O2 cells have a complex dependence on the physicochemical properties of the electrolyte as well as the speciation of the Na+ and superoxide radical anion. All of these factors control the nucleation and growth phenomena as well as electrolyte stability. Smaller discharge particle sizes and largely homogeneous (2.7 ± 0.5 µm) sodium superoxide (NaO2) crystals with only 9% of side products were found in the hybrid electrolyte containing the pyrrolidinium IL with a linear alkyl chain. The long-term cyclability of Na-O2 batteries with high Coulombic efficiency (>90%) was obtained for this electrolyte with fewer side products (20 cycles at 0.5 mA h cm-2). In contrast, rapid failure was observed with the use of the phosphonium-based electrolyte, which strongly stabilizes the superoxide anion. A high discharge capacity (4.46 mA h cm-2) was obtained for the hybrid electrolyte containing the pyrrolidinium-based IL bearing a linear alkyl chain with a slightly lower value (3.11 mA h cm-2) being obtained when the hybrid electrolyte contained similar pyrrolidinium-based IL bearing an alkoxy chain.

12.
Horm Behav ; 136: 105064, 2021 11.
Article in English | MEDLINE | ID: mdl-34653914

ABSTRACT

Agonistic behavior governs the settlement of conflicts among conspecifics for limiting resources. Sex steroids play a critical role in the regulation of agonistic behavior which in turn may produce modulations in hormone titres. In this study we analyzed the association of androgens and estrogens with agonistic behavior in the annual fish Austrolebias reicherti. This native species inhabits temporary ponds that dry out completely during summer, having one of the shortest lifespans among vertebrates. They are highly sexually dimorphic and have a single breeding season during which they reproduce continuously. Here we measured plasma levels of 11-ketotestosterone (11KT) and 17ß-estradiol (E2) in adult males after the resolution of a social conflict and assessed the role of the aromatase conversion of testosterone (T) to E2 in male aggression. Winners had higher levels of 11KT than losers yet; winner 11KT levels did not differ from those of males not exposed to a social challenge. E2 levels did not show differences among winners, losers or control males. However, fights under the aromatase inhibitor Fadrozole were overall less aggressive than control fights. Our results suggest an androgen response to losing a conflict and that the conversion of T to E2 is involved in the regulation of aggressive behavior. Annual fish extreme life history may give new insights on hormone-behavior interactions.


Subject(s)
Androgens , Cyprinodontiformes , Agonistic Behavior , Androgens/pharmacology , Animals , Estrogens/pharmacology , Estrogens/physiology , Gonadal Steroid Hormones , Male
13.
Front Neural Circuits ; 15: 716605, 2021.
Article in English | MEDLINE | ID: mdl-34393727

ABSTRACT

Aggression is an adaptive behavior that plays an important role in gaining access to limited resources. Aggression may occur uncoupled from reproduction, thus offering a valuable context to further understand its neural and hormonal regulation. This review focuses on the contributions from song sparrows (Melospiza melodia) and the weakly electric banded knifefish (Gymnotus omarorum). Together, these models offer clues about the underlying mechanisms of non-breeding aggression, especially the potential roles of neuropeptide Y (NPY) and brain-derived estrogens. The orexigenic NPY is well-conserved between birds and teleost fish, increases in response to low food intake, and influences sex steroid synthesis. In non-breeding M. melodia, NPY increases in the social behavior network, and NPY-Y1 receptor expression is upregulated in response to a territorial challenge. In G. omarorum, NPY is upregulated in the preoptic area of dominant, but not subordinate, individuals. We hypothesize that NPY may signal a seasonal decrease in food availability and promote non-breeding aggression. In both animal models, non-breeding aggression is estrogen-dependent but gonad-independent. In non-breeding M. melodia, neurosteroid synthesis rapidly increases in response to a territorial challenge. In G. omarorum, brain aromatase is upregulated in dominant but not subordinate fish. In both species, the dramatic decrease in food availability in the non-breeding season may promote non-breeding aggression, via changes in NPY and/or neurosteroid signaling.


Subject(s)
Aggression/physiology , Neuroendocrine Cells/metabolism , Neurosteroids/metabolism , Seasons , Territoriality , Aggression/psychology , Animals , Birds , Fishes
14.
Article in English | MEDLINE | ID: mdl-32793118

ABSTRACT

Aggressive behaviors occurring dissociated from the breeding season encourage the search of non-gonadal underlying regulatory mechanisms. Brain estrogen has been shown to be a key modulator of this behavior in bird and mammal species, and it remains to be understood if this is a common mechanism across vertebrates. This review focuses on the contributions of Gymnotus omarorum, the first teleost species in which estrogenic modulation of non-breeding aggression has been demonstrated. Gymnotus omarorum displays year-long aggression, which has been well characterized in the non-breeding season. In the natural habitat, territory size is independent of sex and determined by body size. During the breeding season, on the other hand, territory size no longer correlates to body size, but rather to circulating estrogens and gonadosomatic index in females, and 11-ketotestosterone in males. The hormonal mechanisms underlying non-breeding aggression have been explored in dyadic encounters in lab settings. Males and females display robust aggressive contests, whose outcome depends only on body size asymmetry. This agonistic behavior is independent of gonadal hormones and fast acting androgens. Nevertheless, it is dependent on fast acting estrogenic action, as acute aromatase blockers affect aggression engagement, intensity, and outcome. Transcriptomic profiling in the preoptic area region shows non-breeding individuals express aromatase and other steroidogenic enzyme transcripts. This teleost model reveals there is a role of brain estrogen in the control of non-breeding aggression which seems to be common among distant vertebrate species.


Subject(s)
Aggression , Behavior, Animal , Electric Fish/physiology , Gonadal Steroid Hormones/metabolism , Models, Animal , Territoriality , Animals , Gene Expression Regulation
15.
Sci Rep ; 10(1): 9496, 2020 06 11.
Article in English | MEDLINE | ID: mdl-32528029

ABSTRACT

Differences in social status are often mediated by agonistic encounters between competitors. Robust literature has examined social status-dependent brain gene expression profiles across vertebrates, yet social status and reproductive state are often confounded. It has therefore been challenging to identify the neuromolecular mechanisms underlying social status independent of reproductive state. Weakly electric fish, Gymnotus omarorum, display territorial aggression and social dominance independent of reproductive state. We use wild-derived G. omarorum males to conduct a transcriptomic analysis of non-breeding social dominance relationships. After allowing paired rivals to establish a dominance hierarchy, we profiled the transcriptomes of brain sections containing the preoptic area (region involved in regulating aggressive behaviour) in dominant and subordinate individuals. We identified 16 differentially expressed genes (FDR < 0.05) and numerous genes that co-varied with behavioural traits. We also compared our results with previous reports of differential gene expression in other teleost species. Overall, our study establishes G. omarorum as a powerful model system for understanding the neuromolecular bases of social status independent of reproductive state.


Subject(s)
Agonistic Behavior , Brain/metabolism , Electric Fish , Gene Expression Profiling , Animals , Molecular Sequence Annotation , Social Dominance
16.
PLoS One ; 15(6): e0228976, 2020.
Article in English | MEDLINE | ID: mdl-32542049

ABSTRACT

In this study, we focused on the seasonal variation of the determinants of territory size in the weakly electric fish Gymnotus omarorum. This species is a seasonal breeder that displays year-round territorial aggression. Female and male dyads exhibit indistinguishable non-breeding territorial agonistic behavior and body size is the only significant predictor of contest outcome. We conducted field surveys across seasons that included the identification of individual location, measurements of water physico-chemical variables, characterization of individual morphometric and physiological traits, and their correlation to spatial distribution. G. omarorum tolerates a wide range of dissolved oxygen concentration, and territory size correlated positively with dissolved oxygen in both seasons. In the non-breeding season, territory size was sexually monomorphic and correlated only with body size. In the breeding season, territory size no longer correlated with body size but differed between sexes: (i) the overall spatial arrangement was sexually biased, (ii) territory size depended on gonadal hormones in both sexes, which was expected for males, but not previously reported in females, (iii) female territory size showed a positive relationship with gonadal size, and (iv) females showed relatively larger territories than males. This study demonstrates seasonal changes in the determinants of territory size and thus contributes to the understanding of the mechanisms underlying the behavioral plasticity natural territorial behavior.


Subject(s)
Behavior, Animal , Electric Fish , Seasons , Animals , Body Size , Electric Fish/anatomy & histology , Environment , Social Behavior , Spatial Analysis
17.
Physiol Behav ; 220: 112883, 2020 06 01.
Article in English | MEDLINE | ID: mdl-32199998

ABSTRACT

Aggressive behaviors are widespread among animals and are critical in the competition for resources. The physiological mechanisms underlying aggression have mostly been examined in breeding males, in which gonadal androgens, acting in part through their aromatization to estrogens, have a key role. There are two alternative models that contribute to further understanding hormonal mechanisms underlying aggression: aggression displayed in the non-breeding season, when gonadal steroids are low, and female aggression. In this study we approach, for the first time, the modulatory role of estrogens and androgens upon non-breeding aggression in a wild female teleost fish. We characterized female aggression in the weakly electric fish Gymnotus omarorum and carried out acute treatments 1 h prior to agonistic encounters in dyads treated with either an aromatase inhibitor or an antagonist of androgen receptors. Anti-androgen treatment had no effect on behavior whereas acute aromatase inhibition caused a strong distortion of aggressive behavior. Territorial non-breeding aggression was robust and depended on rapid estrogen actions to maintain high levels of aggression, and ultimately reach conflict resolution from which dominant/subordinate status emerged. Our results, taken together with our own reports in males and the contributions from non-breeding aggression in bird and mammal models, suggest a common strategy involving fast-acting estrogens in the control of this behavior across species. In addition, further analysis of female non-breeding aggression may shed light on potential sexual differences in the fine tuning of social behaviors.


Subject(s)
Aggression , Electric Fish , Animals , Breeding , Female , Gonadal Steroid Hormones , Male , Seasons , Territoriality , Testosterone
18.
Dev Neurobiol ; 80(1-2): 70-80, 2020 01.
Article in English | MEDLINE | ID: mdl-31955508

ABSTRACT

Like stomatogastric activity in crustaceans, vocalization in teleosts and frogs, and locomotion in mammals, the electric organ discharge (EOD) of weakly electric fish is a rhythmic and stereotyped electromotor pattern. The EOD, which functions in both perception and communication, is controlled by a two-layered central pattern generator (CPG), the electromotor CPG, which modifies its basal output in response to environmental and social challenges. Despite major anatomo-functional commonalities in the electromotor CPG across electric fish species, we show that Gymnotus omarorum and Brachyhypopomus gauderio have evolved divergent neural processes to transiently modify the CPG outputs through descending fast neurotransmitter inputs to generate communication signals. We also present two examples of electric behavioral displays in which it is possible to separately analyze the effects of neuropeptides (mid-term modulation) and gonadal steroid hormones (long-term modulation) upon the CPG. First, the nonbreeding territorial aggression of G. omarorum has been an advantageous model to analyze the status-dependent modulation of the excitability of CPG neuronal components by vasotocin. Second, the seasonal and sexually dimorphic courtship signals of B. gauderio have been useful to understand the effects of sex steroids on the responses to glutamatergic inputs in the CPG. Overall, the electromotor CPG functions in a regime that safeguards the EOD waveform. However, prepacemaker influences and hormonal modulation enable an enormous versatility and allows the EOD to adapt its functional state in a species-, sex-, and social context-specific manners.


Subject(s)
Behavior, Animal/physiology , Biogenic Amines/physiology , Biological Clocks/physiology , Central Pattern Generators/physiology , Gonadal Steroid Hormones/physiology , Gymnotiformes/physiology , Neuropeptides/physiology , Animals , Biogenic Amines/metabolism , Central Pattern Generators/metabolism , Gonadal Steroid Hormones/metabolism , Gymnotiformes/metabolism , Neuropeptides/metabolism , Species Specificity
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