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1.
PLoS One ; 19(7): e0306611, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38995904

RESUMO

In insects, biogenic amines function as neurotransmitters, neuromodulators, and neurohormones, influencing various behaviors, including those related to reproduction such as response to sex pheromones, oogenesis, oviposition, courtship, and mating. Octopamine (OA), an analog of the vertebrate norepinephrine, is synthesized from the biogenic amine tyramine by the enzyme tyramine ß-hydroxylase (TßH). Here, we investigate the mechanisms and target genes underlying the role of OA in successful reproduction in females of Rhodnius prolixus, a vector of Chagas disease, by downregulating TßH mRNA expression (thereby reducing OA content) using RNA interference (RNAi), and in vivo and ex vivo application of OA. Injection of females with dsTßH impairs successful reproduction at least in part, by decreasing the transcript expression of enzymes involved in juvenile hormone biosynthesis, the primary hormone for oogenesis in R. prolixus, thereby interfering with oogenesis, ovulation and oviposition. This study offers valuable insights into the involvement of OA for successful reproduction in R. prolixus females. Understanding the reproductive biology of R. prolixus is crucial in a medical context for controlling the spread of the disease.


Assuntos
Octopamina , Oogênese , Oviposição , Reprodução , Rhodnius , Animais , Rhodnius/genética , Rhodnius/fisiologia , Rhodnius/metabolismo , Octopamina/metabolismo , Feminino , Interferência de RNA , Oxigenases de Função Mista/metabolismo , Oxigenases de Função Mista/genética , Hormônios Juvenis/metabolismo , Ovulação , Proteínas de Insetos/metabolismo , Proteínas de Insetos/genética
2.
Learn Mem ; 31(5)2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38862169

RESUMO

Octopamine, the functional analog of noradrenaline, modulates many different behaviors and physiological processes in invertebrates. In the central nervous system, a few octopaminergic neurons project throughout the brain and innervate almost all neuropils. The center of memory formation in insects, the mushroom bodies, receive octopaminergic innervations in all insects investigated so far. Different octopamine receptors, either increasing or decreasing cAMP or calcium levels in the cell, are localized in Kenyon cells, further supporting the release of octopamine in the mushroom bodies. In addition, different mushroom body (MB) output neurons, projection neurons, and dopaminergic PAM cells are targets of octopaminergic neurons, enabling the modulation of learning circuits at different neural sites. For some years, the theory persisted that octopamine mediates rewarding stimuli, whereas dopamine (DA) represents aversive stimuli. This simple picture has been challenged by the finding that DA is required for both appetitive and aversive learning. Furthermore, octopamine is also involved in aversive learning and a rather complex interaction between these biogenic amines seems to modulate learning and memory. This review summarizes the role of octopamine in MB function, focusing on the anatomical principles and the role of the biogenic amine in learning and memory.


Assuntos
Aprendizagem , Memória , Corpos Pedunculados , Octopamina , Octopamina/metabolismo , Octopamina/farmacologia , Corpos Pedunculados/fisiologia , Corpos Pedunculados/efeitos dos fármacos , Animais , Memória/fisiologia , Memória/efeitos dos fármacos , Aprendizagem/fisiologia , Aprendizagem/efeitos dos fármacos , Dopamina/metabolismo , Insetos/fisiologia , Neurônios/fisiologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo
3.
ACS Synth Biol ; 13(6): 1762-1772, 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38815614

RESUMO

In this study, we designed an artificial pathway composed of tyramine ß-hydroxylase (TBH) and phenylethanolamine N-methyltransferase (PNMT) for the biosynthesis of both octopamine and synephrine. As most TBH and PNMT originate from eukaryotic animals and plants, the heterologous expression and identification of functional TBH and PNMT are critical for establishing the pathway in mode microorganisms like Escherichia coli. Here, three TBHs were evaluated, and only TBH from Drosophila melanogaster was successfully expressed in the soluble form in E. coli. Its expression was promoted by evaluating the effects of different expression strategies. The specific enzyme activity of TBH was optimized up to 229.50 U·g-1, and the first step in the biosynthetic pathway was successfully established and converted tyramine to synthesize 0.10 g/L of octopamine. Furthermore, the second step to produce synephrine from octopamine was developed by screening PNMT, enhancing enzyme activity, and optimizing reaction conditions, with a maximum synephrine production of 2.02 g/L. Finally, based on the optimization of the reaction conditions for each individual reaction, the one-pot cascade reaction for synthesizing synephrine from tyramine was constructed by combining the TBH and PNMT. The synthetic synephrine reached 30.05 mg/L with tyramine as substrate in the two-step enzyme cascade system. With further optimization and amplification, the titers of octopamine and synephrine were increased to 0.45 and 0.20 g/L, respectively, with tyramine as substrate. This work was the first achievement of the biosynthesis of octopamine and synephrine to date.


Assuntos
Drosophila melanogaster , Escherichia coli , Oxigenases de Função Mista , Octopamina , Feniletanolamina N-Metiltransferase , Sinefrina , Octopamina/metabolismo , Sinefrina/metabolismo , Animais , Drosophila melanogaster/metabolismo , Escherichia coli/metabolismo , Escherichia coli/genética , Feniletanolamina N-Metiltransferase/metabolismo , Feniletanolamina N-Metiltransferase/genética , Oxigenases de Função Mista/metabolismo , Oxigenases de Função Mista/genética , Tiramina/metabolismo , Tiramina/biossíntese , Vias Biossintéticas , Engenharia Metabólica/métodos
4.
Neuron ; 112(14): 2315-2332.e8, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-38795709

RESUMO

Hungry animals need compensatory mechanisms to maintain flexible brain function, while modulation reconfigures circuits to prioritize resource seeking. In Drosophila, hunger inhibits aversively reinforcing dopaminergic neurons (DANs) to permit the expression of food-seeking memories. Multitasking the reinforcement system for motivation potentially undermines aversive learning. We find that chronic hunger mildly enhances aversive learning and that satiated-baseline and hunger-enhanced learning require endocrine adipokinetic hormone (AKH) signaling. Circulating AKH influences aversive learning via its receptor in four neurons in the ventral brain, two of which are octopaminergic. Connectomics revealed AKH receptor-expressing neurons to be upstream of several classes of ascending neurons, many of which are presynaptic to aversively reinforcing DANs. Octopaminergic modulation of and output from at least one of these ascending pathways is required for shock- and bitter-taste-reinforced aversive learning. We propose that coordinated enhancement of input compensates for hunger-directed inhibition of aversive DANs to preserve reinforcement when required.


Assuntos
Aprendizagem da Esquiva , Neurônios Dopaminérgicos , Proteínas de Drosophila , Fome , Hormônios de Inseto , Reforço Psicológico , Animais , Neurônios Dopaminérgicos/fisiologia , Neurônios Dopaminérgicos/metabolismo , Fome/fisiologia , Aprendizagem da Esquiva/fisiologia , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Hormônios de Inseto/metabolismo , Ácido Pirrolidonocarboxílico/análogos & derivados , Ácido Pirrolidonocarboxílico/metabolismo , Oligopeptídeos , Drosophila melanogaster , Drosophila , Octopamina/metabolismo , Dopamina/metabolismo , Encéfalo/fisiologia , Encéfalo/metabolismo
5.
Elife ; 122024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38655926

RESUMO

The brain regulates food intake in response to internal energy demands and food availability. However, can internal energy storage influence the type of memory that is formed? We show that the duration of starvation determines whether Drosophila melanogaster forms appetitive short-term or longer-lasting intermediate memories. The internal glycogen storage in the muscles and adipose tissue influences how intensely sucrose-associated information is stored. Insulin-like signaling in octopaminergic reward neurons integrates internal energy storage into memory formation. Octopamine, in turn, suppresses the formation of long-term memory. Octopamine is not required for short-term memory because octopamine-deficient mutants can form appetitive short-term memory for sucrose and to other nutrients depending on the internal energy status. The reduced positive reinforcing effect of sucrose at high internal glycogen levels, combined with the increased stability of food-related memories due to prolonged periods of starvation, could lead to increased food intake.


Deciding what and how much to eat is a complex biological process which involves balancing many types of information such as the levels of internal energy storage, the amount of food previously available in the environment, the perceived value of certain food items, and how these are remembered. At the molecular level, food contains carbohydrates that are broken down to produce glucose, which is then delivered to cells under the control of a hormone called insulin. There, glucose molecules are either immediately used or stored as glycogen until needed. Insulin signalling is also known to interact with the brain's decision-making systems that control eating behaviors; however, how our brains balance food intake with energy storage is poorly understood. Berger et al. set out to investigate this question using fruit flies as an experimental model. These insects also produce insulin-like molecules which help to relay information about glycogen levels to the brain's decision-making system. In particular, these signals reach a population of neurons that produce a messenger known as octopamine similar to the human noradrenaline, which helps regulate how much the flies find consuming certain types of foods rewarding. Berger et al. were able to investigate the role of octopamine in helping to integrate information about internal and external resource levels, memory formation and the evaluation of different food types. When the insects were fed normally, increased glycogen levels led to foods rich in carbohydrates being rated as less rewarding by the decision-making cells, and therefore being consumed less. Memories related to food intake were also short-lived ­ in other words, long-term 'food memory' was suppressed, re-setting the whole system after every meal. In contrast, long periods of starvation in insects with high carbohydrates resources produced a stable, long-term memory of food and hunger which persisted even after the flies had fed again. This experience also changed their food rating system, with highly nutritious foods no longer being perceived as sufficiently rewarding. As a result, the flies overate. This study sheds new light on the mechanisms our bodies may use to maintain energy reserves when food is limited. The persistence of 'food memory' after long periods of starvation may also explain why losing weight is difficult, especially during restrictive diets. In the future, Berger et al. hope that this knowledge will contribute to better strategies for weight management.


Assuntos
Drosophila melanogaster , Metabolismo Energético , Octopamina , Animais , Drosophila melanogaster/fisiologia , Octopamina/metabolismo , Memória/fisiologia , Glicogênio/metabolismo , Inanição , Sacarose/metabolismo , Memória de Longo Prazo/fisiologia , Ingestão de Alimentos/fisiologia
6.
BMC Res Notes ; 17(1): 46, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38326892

RESUMO

OBJECTIVE: Neurotransmitters have been extensively studied as neural communication molecules. Genetic associations discovered, and indirect intervention studies in Humans and mammals have led to a general proposition that neurotransmitters have a role in structuring of neuronal network during development. olf413 is a Drosophila gene annotated as coding for dopamine beta-monooxygenase enzyme with a predicted function in octopaminergic pathway. The biological function of this gene is very little worked out. In this study we investigate the requirement of olf413 gene function for octopamine biogenesis and developmental patterning of embryonic nervous system. RESULT: In our study we have used the newly characterized neuronal specific allele olf413SG1.1, and the gene disruption strain olf413MI02014 to dissect out the function of olf413. olf413 has an enhancer activity as depicted by reporter GFP expression, in the embryonic ventral nerve cord, peripheral nervous system and the somatic muscle bundles. Homozygous loss of function mutants show reduced levels of octopamine, and this finding supports the proposed function of the gene in octopamine biogenesis. Further, loss of function of olf413 causes embryonic lethality. FasII staining of these embryos reveal a range of phenotypes in the central and peripheral motor nerves, featuring axonal growth, pathfinding, branching and misrouting defects. Our findings are important as they implicate a key functional requirement of this gene in precise axonal patterning events, a novel developmental role imparted for an octopamine biosynthesis pathway gene in structuring of embryonic nervous system.


Assuntos
Proteínas de Drosophila , Drosophila melanogaster , Animais , Humanos , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Octopamina/metabolismo , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Axônios , Neurotransmissores/metabolismo , Mamíferos/metabolismo
7.
Artigo em Inglês | MEDLINE | ID: mdl-38346534

RESUMO

In a recent mechanistic study, octopamine was shown to promote proton transport over the branchial epithelium in green crabs, Carcinus maenas. Here, we follow up on this finding by investigating the involvement of octopamine in an environmental and physiological context that challenges acid-base homeostasis, the response to short-term high pCO2 exposure (400 Pa) in a brackish water environment. We show that hyperregulating green crabs experienced a respiratory acidosis as early as 6 h of exposure to hypercapnia, with a rise in hemolymph pCO2 accompanied by a simultaneous drop of hemolymph pH. The slightly delayed increase in hemolymph HCO3- observed after 24 h helped to restore hemolymph pH to initial values by 48 h. Circulating levels of the biogenic amine octopamine were significantly higher in short-term high pCO2 exposed crabs compared to control crabs after 48 h. Whole animal metabolic rates, intracellular levels of octopamine and cAMP, as well as branchial mitochondrial enzyme activities for complex I + III and citrate synthase were unchanged in posterior gill #7 after 48 h of hypercapnia. However, application of octopamine in gill respirometry experiments suppressed branchial metabolic rate in posterior gills of short-term high pCO2 exposed animals. Furthermore, branchial enzyme activity of cytochrome C oxidase decreased in high pCO2 exposed crabs after 48 h. Our results indicate that hyperregulating green crabs are capable of quickly counteracting a hypercapnia-induced respiratory acidosis. The role of octopamine in the acclimation of green crabs to short-term hypercapnia seems to entail the alteration of branchial metabolic pathways, possibly targeting mitochondrial cytochrome C in the gill. Our findings help advancing our current limited understanding of endocrine components in hypercapnia acclimation. SUMMARY STATEMENT: Acid-base compensation upon short-term high pCO2 exposure in hyperregulating green crabs started after 6 h and was accomplished by 48 h with the involvement of the biogenic amine octopamine, accumulation of hemolymph HCO3-, and regulation of mitochondrial complex IV (cytochrome C oxidase).


Assuntos
Acidose Respiratória , Braquiúros , Decápodes , Animais , Hipercapnia/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Octopamina/metabolismo , Acidose Respiratória/metabolismo , Braquiúros/fisiologia , Brânquias/metabolismo
8.
G3 (Bethesda) ; 14(3)2024 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-38244217

RESUMO

Aminergic signaling is known to play a critical role in regulating female reproductive processes in both mammals and insects. In Drosophila, the ortholog of noradrenaline, octopamine, is required for ovulation as well as several other female reproductive processes. Two octopamine receptors have already been shown to be expressed in the Drosophila reproductive tract and to be required for egg-laying: OAMB and Octß2R. The Drosophila genome contains 4 additional octopamine receptors-Octα2R, Octß1R, Octß3R, and Oct-TyrR-but their cellular patterns of expression in the reproductive tract and potential contribution(s) to egg-laying are not known. In addition, the mechanisms by which OAMB and Octß2R regulate reproduction are incompletely understood. Using a panel of MiMIC Gal4 lines, we show that Octα2R, Octß1R, Octß3R, and Oct-TyrR receptors are not detectable in either epithelium or muscle but are clearly expressed in neurons within the female fly reproductive tract. Optogenetic activation of neurons that express at least 3 types of octopamine receptors stimulates contractions in the lateral oviduct. We also find that octopamine stimulates calcium transients in the sperm storage organs and that its effects in spermathecal, secretory cells, can be blocked by knock-down of OAMB. These data extend our understanding of the pathways by which octopamine regulates egg-laying in Drosophila and raise the possibility that multiple octopamine receptor subtypes could play a role in this process.


Assuntos
Proteínas de Drosophila , Drosophila , Receptores de Amina Biogênica , Animais , Feminino , Masculino , Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Octopamina/metabolismo , Sêmen/metabolismo , Proteínas de Drosophila/metabolismo , Mamíferos
9.
J Insect Physiol ; 152: 104597, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38072185

RESUMO

Insects' thermoregulatory processes depend on thermosensation and further processing of thermal information in the nervous system. It is commonly known that thermosensation involves thermoreceptors, including members of the TRP receptor family, but the involvement of neurotransmitters in thermoregulatory pathways remains unstudied. We conducted test to determine whether octopamine, a biogenic amine that acts as a neurotransmitter and neurohormone in insects, is involved in TRP-induced thermoregulatory responses in Periplaneta americana. We used capsaicin, an activator of the heat-sensitive TRP channel, Painless, to induce thermoregulatory response in cockroaches. Then, we evaluated the behavioural (thermal preferences and grooming), physiological (heart rate) and biochemical responses of insects to capsaicin, octopamine and phentolamine - octopaminergic receptor blocker. Capsaicin, similar to octopamine, increased cockroaches' grooming activity and heart rate. Moreover, octopamine level and protein kinase A (PKA) activity significantly increased after capsaicin treatment. Blocking octopaminergic receptors with phentolamine diminished cockroaches' response to capsaicin - thermoregulatory behaviour, grooming and heart rate were abolished. The results indicate that octopamine is a neurotransmitter secreted in insects after the activation of heat receptors.


Assuntos
Baratas , Periplaneta , Animais , Periplaneta/fisiologia , Capsaicina/metabolismo , Capsaicina/farmacologia , Octopamina/farmacologia , Octopamina/metabolismo , Fentolamina/farmacologia , Baratas/metabolismo , Neurotransmissores/metabolismo
10.
J Genet ; 1022023.
Artigo em Inglês | MEDLINE | ID: mdl-38073169

RESUMO

Olf413 gene annotated as CG12673 in the genome of Drosophila melanogaster has been predicted to code for a protein with putative function in octopamine biosynthesis. The expression pattern and the biological function of the gene awaits investigation. The present study is the first report where we describe its expression in the late pupal brain as depicted by enhancer-driven green fluorescent protein (GFP) expression. With experiments using loss of function olf413 mutant flies, we have demonstrated that olf413 function is essential for motor activity, gravity sensing and spatial balancing of the body against gravity during climbing.


Assuntos
Proteínas de Drosophila , Drosophila melanogaster , Animais , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Octopamina/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Encéfalo/metabolismo
11.
Cells ; 12(21)2023 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-37947593

RESUMO

Circadian rhythm disturbances are associated with various negative health outcomes, including an increasing incidence of chronic diseases with high societal costs. While exercise can protect against the negative effects of rhythm disruption, it is not available to all those impacted by sleep disruptions, in part because sleep disruption itself reduces exercise capacity. Thus, there is a need for therapeutics that bring the benefits of exercise to this population. Here, we investigate the relationship between exercise and circadian disturbances using a well-established Drosophila model of circadian rhythm loss, the Clkout mutant. We find that Clkout causes reduced exercise capacity, measured as post-training endurance, flight performance, and climbing speed, and these phenotypes are not rescued by chronic exercise training. However, exogenous administration of a molecule known to mediate the effects of chronic exercise, octopamine (OA), was able to effectively rescue mutant exercise performance, including the upregulation of other known exercise-mediating transcripts, without restoring the circadian rhythms of mutants. This work points the way toward the discovery of novel therapeutics that can restore exercise capacity in patients with rhythm disruption.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Humanos , Octopamina/farmacologia , Proteínas de Drosophila/genética , Ritmo Circadiano/genética , Fenótipo
12.
Transl Psychiatry ; 13(1): 367, 2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-38036526

RESUMO

Neurexins are synaptic adhesion molecules that play diverse roles in synaptic development, function, maintenance, and plasticity. Neurexin genes have been associated with changes in human behavior, where variants in NRXN1 are associated with autism, schizophrenia, and Tourette syndrome. While NRXN1, NRXN2, and NRXN3 all encode major α and ß isoforms, NRXN1 uniquely encodes a γ isoform, for which mechanistic roles in behavior have yet to be defined. Here, we show that both α and γ isoforms of neurexin/nrx-1 are required for the C. elegans behavioral response to food deprivation, a sustained period of hyperactivity upon food loss. We find that the γ isoform regulates initiation and the α isoform regulates maintenance of the behavioral response to food deprivation, demonstrating cooperative function of multiple nrx-1 isoforms in regulating a sustained behavior. The γ isoform alters monoamine signaling via octopamine, relies on specific expression of NRX-1 isoforms throughout the relevant circuit, and is independent of neuroligin/nlg-1, the canonical trans-synaptic partner of nrx-1. The α isoform regulates the pre-synaptic structure of the octopamine producing RIC neuron and its maintenance role is conditional on neuroligin/nlg-1. Collectively, these results demonstrate that neurexin isoforms can have separate behavioral roles and act cooperatively across neuronal circuits to modify behavior, highlighting the need to directly analyze and consider all isoforms when defining the contribution of neurexins to behavior.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animais , Humanos , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Octopamina/metabolismo , Moléculas de Adesão Celular Neuronais/genética , Moléculas de Adesão Celular Neuronais/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Neurônios/metabolismo , Sinapses/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo
13.
J Evol Biol ; 36(10): 1494-1502, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37737492

RESUMO

Mating interactions are rife with conflict because the evolutionary interests of males and females seldom coincide. Intersexual conflict affects sexual selection, yet the proximate factors underlying male coercive ability and female resistance are poorly understood. Male combat outcomes are often influenced by bite force, with superior biters being more likely to achieve victory over poorer biters in a range of species, including crickets. If good performers also achieve mating success through sexual coercion, then bite force might play a role in intersexual conflict as well. We tested the capacity of bite force to influence mating interactions in house crickets both directly by measuring bite forces of males and females and by altering male bite capacity through neuropharmacological manipulation. In addition, the invertebrate neurotransmitter octopamine both mediates aggression and underlies motivation to bite in male house crickets. By blocking octopamine receptors through the application of an antagonist, epinastine, we tested the effects of reduced bite force on male mating success. Our results show that male bite capacity, in combination with body size, influences both the likelihood and the outcomes of mating interactions, whereas treatment of males with epinastine eliminates motivation to mate. Our results suggest a functional role for bite force in affecting both sexual conflict and sexual selection and expand our knowledge of the influence of biogenic amines on reproductive behaviour.


Assuntos
Gryllidae , Comportamento Sexual Animal , Animais , Feminino , Masculino , Comportamento Sexual Animal/fisiologia , Gryllidae/fisiologia , Força de Mordida , Octopamina/farmacologia , Tamanho Corporal
14.
Fish Shellfish Immunol ; 142: 109096, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37758094

RESUMO

Stress responses impact the immune systems, growth, and reproduction of aquatic organisms. Neuroendocrine regulation involving biogenic amines, including octopamine (OA), plays a pivotal role in maintaining physiological balance during stress. This study focuses on the synthesis pathway of OA, particularly the role of tyramine beta hydroxylase (TBH), in Litopenaeus vannamei under stress. TBH catalyzes the conversion of tyramine to OA, a process critical for physiological responses. The present study demonstrated LvTBH at the protein level under different stress conditions during acute (0.5, 1, 2 h) and chronic stress (24, 72, 168 h) periods. LvTBH increased in thoracic ganglia within 2 h under hyperthermal stress, accompanied by elevated OA levels. Conversely, LvTBH decreased in the brain and circumesophageal connective tissues during acute and chronic hypothermal stress. Additionally, LvTBH increased in the brain and circumesophageal connective tissues under acute infection stress, coinciding with elevated OA levels. These findings collectively contribute to a more intricate understanding of the neuroendocrine dynamics within L. vannamei under stress, underscoring the role of TBH in orchestrating responses crucial for adaptation.


Assuntos
Octopamina , Penaeidae , Animais , Octopamina/metabolismo , Vibrio alginolyticus/fisiologia , Salinidade , Oxigenases de Função Mista , Tiramina
15.
J Comp Physiol B ; 193(5): 509-522, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37563322

RESUMO

Crustaceans' endocrinology is a vastly understudied area of research. The major focus of the studies on this topic to date has been on the molting cycle (and in particular, the role of crustacean hyperglycemic hormone (CHH)), as well as the role of other hormones in facilitating physiological phenotypic adjustments to salinity changes. Additionally, while many recent studies have been conducted on the acclimation and adaptation capacity of crustaceans to a changing environment, only few have investigated internal hormonal balance especially with respect to an endocrine response to environmental challenges. Consequently, our study aimed to identify and characterize endocrine components of acid-base regulation in the European green crab, Carcinus maenas. We show that both the biogenic amine octopamine (OCT) and the CHH are regulatory components of branchial acid-base regulation. While OCT suppressed branchial proton excretion, CHH seemed to promote it. Both hormones were also capable of enhancing branchial ammonia excretion. Furthermore, mRNA abundance for branchial receptors (OCT-R), or G-protein receptor activated soluble guanylate cyclase (sGC1b), are affected by environmental change such as elevated pCO2 (hypercapnia) and high environmental ammonia (HEA). Our findings support a role for both OCT and CHH in the general maintenance of steady-state acid-base maintenance in the gill, as well as regulating the acid-base response to environmental challenges that C. maenas encounters on a regular basis in the habitats it dwells in and more so in the future ocean.


Assuntos
Braquiúros , Hormônios de Invertebrado , Animais , Braquiúros/fisiologia , Octopamina , Amônia , Proteínas de Artrópodes
16.
Nat Commun ; 14(1): 4338, 2023 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-37468470

RESUMO

Malaria mosquitoes acoustically detect their mating partners within large swarms that form transiently at dusk. Indeed, male malaria mosquitoes preferably respond to female flight tones during swarm time. This phenomenon implies a sophisticated context- and time-dependent modulation of mosquito audition, the mechanisms of which are largely unknown. Using transcriptomics, we identify a complex network of candidate neuromodulators regulating mosquito hearing in the species Anopheles gambiae. Among them, octopamine stands out as an auditory modulator during swarm time. In-depth analysis of octopamine auditory function shows that it affects the mosquito ear on multiple levels: it modulates the tuning and stiffness of the flagellar sound receiver and controls the erection of antennal fibrillae. We show that two α- and ß-adrenergic-like octopamine receptors drive octopamine's auditory roles and demonstrate that the octopaminergic auditory control system can be targeted by insecticides. Our findings highlight octopamine as key for mosquito hearing and mating partner detection and as a potential novel target for mosquito control.


Assuntos
Anopheles , Inseticidas , Malária , Animais , Masculino , Feminino , Inseticidas/farmacologia , Adrenérgicos , Octopamina , Audição , Controle de Mosquitos , Malária/prevenção & controle , Anopheles/fisiologia , Resistência a Inseticidas
17.
Front Cell Infect Microbiol ; 13: 1176013, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37305408

RESUMO

Control of ticks and tick-borne pathogens is a priority for human and animal health. Livestock-holders extensively rely on acaricide applications for tick control. Different groups of acaricides including cypermethrin and amitraz have been consistently used in Pakistan. There has been a gap in understanding the susceptibility or resistance of Rhipicephalus microplus, the most prevalent tick in Pakistan, to acaricides. The present study aimed to molecularly characterize cypermethrin and amitraz targeted genes such as voltage-gated sodium channel (VGSC) and octopamine tyramine (OCT/Tyr) of R. microplus ticks in Khyber Pakhtunkhwa (KP), Pakistan to monitor the acaricides resistance. Tick specimens were collected from cattle and buffaloes in northern (Chitral, Shangla, Swat, Dir, and Buner), central (Peshawar, Mardan, Charsadda, Swabi, and Nowshera), and southern districts (Kohat, Karak, Lakki Marwat, Tank, and Dera Ismail Khan) of KP, Pakistan. Different concentrations of commercially available cypermethrin (10%) and amitraz (12.5%) were prepared for in vitro larval immersion tests (LIT). In LIT, the average mortality rate of immersed larvae was recorded that was increased gradually with an increase in the concentration of specific acaricide. The larvae's highest mortality rates (94.5% and 79.5%) were observed at 100-ppm of cypermethrin and amitraz, respectively. A subset of 82 R. microplus ticks was subjected to extract genomic DNA, followed by PCR to amplify partial fragments of VGSC (domain-II) and OCT/Tyr genes. The BLAST results of the consensus sequence of VGSC gene (domain-II) showed 100% identity with the acaricides susceptible tick sequence from the United States (reference sequence). Obtained identical sequences of OCT/Tyr genes showed maximum identity (94-100%) with the identical sequences reported from Australia (reference sequence), India, Brazil, Philippines, USA, South Africa, and China. Thirteen single nucleotide polymorphisms (10 synonymous and three non-synonymous) were observed at various positions of partial OCT/Tyr gene fragments. The SNP at position A-22-C (T-8-P) in OCT/Tyr gene has been linked to amitraz resistance in R. microplus ticks. Molecular analysis and LIT bioassay's findings indicate the availability of resistant R. microplus ticks in the KP region. To our understanding, this is the first preliminary study to monitor cypermethrin and amitraz resistance via molecular profiling of cypermethrin and amitraz targeted genes (VGSC and OCT/Tyr) in combination with in vitro bioassays (LIT) in R. microplus ticks from Pakistan.


Assuntos
Acaricidas , Rhipicephalus , Humanos , Animais , Bovinos , Octopamina , Tiramina , Rhipicephalus/genética , Acaricidas/farmacologia , Larva/genética
18.
Neurobiol Learn Mem ; 203: 107778, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37257558

RESUMO

Aminergic neurons mediate reward signals in mammals and insects. In crickets, we showed that blockade of synaptic transmission from octopamine neurons (OANs) impairs conditioning of an odor (conditioned stimulus, CS) with water or sucrose (unconditioned stimulus, US) and execution of a conditioned response (CR) to the CS. It has not yet been established, however, whether findings in crickets can be applied to other species of insects. In this study, we investigated the roles of OANs in conditioning of salivation, monitored by activities of salivary neurons, and in execution of the CR in cockroaches (Periplaneta americana). We showed that injection of epinastine (an OA receptor antagonist) into the head hemolymph impaired both conditioning and execution of the CR, in accordance with findings in crickets. Moreover, local injection of epinastine into the vertical lobes of the mushroom body (MB), the center for associative learning and control of the CR, impaired execution of the CR, whereas injection of epinastine into the calyces of the MB or the antennal lobes (primary olfactory centers) did not. We propose that OANs in the MB vertical lobes play critical roles in the execution of the CR in cockroaches. This is analogous to the fact that midbrain dopamine neurons govern execution of learned actions in mammals.


Assuntos
Baratas , Animais , Octopamina , Corpos Pedunculados , Neurônios Dopaminérgicos/fisiologia , Mamíferos
19.
Pest Manag Sci ; 79(9): 3211-3217, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37036086

RESUMO

BACKGROUND: Amitraz is a broad-spectrum formamidine acaricide proven to be effective against mites in all development stages. Under acidic conditions, amitraz is hydrolyzed to N2 -(2,4-dimethylphenyl)-N1 -methyformamidine (DPMF), an active metabolite for mite control. Octopamine and tyramine receptors are well known targets of amitraz. Until now, no research has been conducted about the amitraz target in Tetranychus cinnabarinus. This study aimed to identify the target genes of amitraz in T. cinnabarinus and reveal the mechanisms behind the differential acaricidal activities of amitraz and DPMF. RESULTS: Analysis of the toxicity, stress expression, target sensitivity and binding site of amitraz against T. cinnabarinus showed that TcOctß2R was the main target gene of amitraz. DPMF had more potent acaricidal activity against T. cinnabarinus and was more effective at activating TcOctß2R than amitraz. Furthermore, the three synergists had no significant effect on amitraz and DPMF, indicating that the detoxification metabolism was not related to the difference in acaricidal activity. CONCLUSION: In this study, TcOctß2R was identified as the main target gene of amitraz against T. cinnabarinus. The divergence of target binding was responsible for the difference in acaricidal activity between amitraz and DPMF. The results also revealed the physiological and pharmacological functions of octopamine receptors (OARs) in T. cinnabarinus and could provide a basis for the design of new acaricides, with OARs as a special target. © 2023 Society of Chemical Industry.


Assuntos
Acaricidas , Tetranychidae , Animais , Acaricidas/farmacologia , Toluidinas/farmacologia , Tetranychidae/genética , Octopamina/farmacologia
20.
Proc Natl Acad Sci U S A ; 120(17): e2217396120, 2023 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-37068235

RESUMO

Octopamine is a well-established invertebrate neurotransmitter involved in fight or flight responses. In mammals, its function was replaced by epinephrine. Nevertheless, it is present at trace amounts and can modulate the release of monoamine neurotransmitters by a yet unidentified mechanism. Here, through a multidisciplinary approach utilizing in vitro and in vivo models of α-synucleinopathy, we uncovered an unprecedented role for octopamine in driving the conversion from toxic to neuroprotective astrocytes in the cerebral cortex by fostering aerobic glycolysis. Physiological levels of neuron-derived octopamine act on astrocytes via a trace amine-associated receptor 1-Orai1-Ca2+-calcineurin-mediated signaling pathway to stimulate lactate secretion. Lactate uptake in neurons via the monocarboxylase transporter 2-calcineurin-dependent pathway increases ATP and prevents neurodegeneration. Pathological increases of octopamine caused by α-synuclein halt lactate production in astrocytes and short-circuits the metabolic communication to neurons. Our work provides a unique function of octopamine as a modulator of astrocyte metabolism and subsequent neuroprotection with implications to α-synucleinopathies.


Assuntos
Octopamina , alfa-Sinucleína , Animais , alfa-Sinucleína/metabolismo , Astrócitos/metabolismo , Calcineurina/metabolismo , Lactatos/metabolismo , Mamíferos/metabolismo , Neuroproteção , Neurotransmissores/metabolismo , Octopamina/metabolismo
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