RT Dissertation/Thesis
T1 Stress effects on brain circadian system and monoaminergic activity in rainbow trout : mechanisms and consequences on food intake regulation
T2 Efectos del estrés sobre el sistema circadiano y la actividad monoaminérgica cerebral en la trucha arco iris : mecanismos y consecuencias en la regulación de la ingesta de alimentos
A1 Naderi, Fatemeh
K1 3104.90 Sistemas de Producción Ganadera
K1 3101.04 Productos de la Pesca
K1 3101 Agroquímica
AB Feeding in fish is a critical process in the performance of aquaculture farms. Feeding regulation involves a central regulatory system of the appetite and a peripheral one, which regulates the satiety. The hypothalamus integrates peripheral signals and controls ingestion by orexigenic (NPY, AGRP) and anorexigenic neuropeptides (CART, POMC, CRF). In addition, monoamines (dopamine, serotonin) modulate intake by acting on neuropeptidergic neurons. On the other hand, the feeding is organized rhythmically in time so that the fish adapt their feeding to certain moments of the day. The circadian system ensures the temporary functional organization in organisms. It includes inputs from outside (and inside) information and biological oscillators or clocks that generate rhythmic nervous and endocrine signals that adjust physiology and behavior. The basic mechanism of the biological clock integrates feedback cycles between the transcription and transduction processes of certain genes ("clock genes") and their protein products. The best-known molecular oscillator in vertebrates includes the clock, bmal, per, and cry genes, whose rhythmic expression is maintained autonomously. Its synchronization or adjustment to a specific period requires rhythmic signals linked to photoperiod, food, social interactions, etc., as well as internal neuroendocrine and metabolic signals. In the case of fish, previous studies of the UVI group where the doctoral thesis will be developed, demonstrated rhythms of clock genes in the hypothalamus of rainbow trout, with photoperiod being a primoridal factor for its adjustment, while in the liver the circadian oscillator is basic to maintain the metabolic rythmicity. Despite this, there are many unknowns about the functioning of the circadian system in fish, its adjustment with the environment and how they determine the functional (feeding, motor activity, etc) rhythmicity. Stress conditions adversely affect fish intake, and may also alter physiological and behavioral rhythms. The stress response implicates two endocrine axes that activate the release from the interrenal tissue of the hormones catecholamines and cortisol, which trigger strong physiological and metabolic changes. Previous work by the UVI group has shown that brain monoamines play an essential role in the onset of stress response. It has also been hypothesized that increased levels of cortisol under stress could exert a modulating effect on the body's rhythms and that monoamines could mediate these effects. In fish, however, a possible interaction between monoaminergic systems and circadian oscillators has not been studied, nor are the consequences of stressful situations known. This dissertation aims to increase the knowledge of the brain circadian system in teleost fish and to explore the effect of stress on the molecular mechanisms of the clock and the activity of the monoaminergic systems. It will also evaluate the consequences at the level of the regulation of food intake.  The research plan includes several experimental objectives to be developed in rainbow trout as a model of teleost fish: •	Influence of stress on the circadian system and the role of cortisol. Consequences in the regulation of food intake. •	The role of sirtuin in the effects of stress on hypothalamic clock genes and intake. •	Circadian rhythms of brain monoamines and their adjustment to light and food. Relationship with neuropeptides that regulate the intake. •	Changes in monoaminergic brain activity during chronic stress and the recovery time after stress. •	Role of brain monoamines in the effect of stress on the mechanisms of the circadian clock. Implication of cortisol.
YR 2018
FD 2018-12-04
LK http://hdl.handle.net/11093/1096
UL http://hdl.handle.net/11093/1096
LA eng
DS Investigo
RD 09-oct-2024