Browsing by Subject "Locomotor activity"
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- PublicationEmbargoAge-related changes in fatty acid profile and locomotor activity rhythms in Nothobranchius korthausae(Elsevier, 2011-08-28) Lucas-Sanchez, A; Almaida Pagán, Pedro Francisco; Madrid, Juan A; Costa, J. de; Mendiola, P; FisiologíaThe life cycle of Nothobranchius korthausae, a Cyprinodontiformes fish, was studied in our laboratory to characterise the ageing process. Some morphological changes, such as spine curvature, skin colour, and fin and eye appearance are described. Growth and survival curves reflected a fast life cycle with rapid initial growth until 4 weeks of age, after which the fish grew more slowly before reaching their final size in week 40. Senescence onset was established at week 48 with a decrease in spawn size and viability and a general decline in the animal's appearance (weight and colouration losses, caudal fin degradation, and cataractogenesis). The fatty acid composition changed with age,with high unsaturation in the adult stage as reflected by a high peroxidation index, a condition that is associated with high susceptibility to oxidative damage if elevated reactive oxygen species (ROS) production occurs. Senescent fish had an increase in monounsaturated fatty acid proportions and a lower peroxidation index (226.5±19.7 in adults versus 120.2±19.1 in senescent fish, Pb0.05). The circadian system, as reflected by locomotor activity rhythms, showed noticeable changes with age. Twenty-four-week-old fish (adults) had a robust diurnal rhythm that showed a decrease in total activity, an increase in rhythmfragmentation, and a fall in amplitude and regularity with age. Changes were clearly reflected in the Circadian Function Index variations (0.56, 0.47 and 0.25 at 24, 48 and 72 weeks of age, respectively). In conclusion, N. korthausae appears to be a species with appropriate characteristics for ageing studies because it manifests clear signs of progressive ageing. Comparing species of Nothobranchius genus with different lifespans may be useful for increasing our understanding of the ageing process.
- PublicationEmbargoCircadian activity rhythms during the last days of Nothobranchius rachovii’s life: A descriptive model of circadian system breakdown(Informa Healthcare USA, Inc., 2014-11-25) Lucas-Sánchez, Alejandro; Martínez-Nicolás, Antonio; Madrid, Juan Antonio; Almaida Pagán, Pedro Francisco; Mendiola, Pilar; Costa, Jorge de; FisiologíaSeveral studies have been performed to identify age-related changes in the circadian system (CS) but the impairment of the CS and its chronodisruption at the end of an organism life have not been studied in depth. Aging commonly affects the input pathways into the biological clock or restraints their processing, therefore simplifying the system output, the overt rhythms. The purpose of this work was to do a complete characterization of changes that occurs in the CS in the last stage of a vertebrate organism life and to develop tools able to detect in which moment of the last days of life is the animal, using an overt rhythm, the rest-activity rhythm (RAR). For that, a fish species proposed as model for aging studies, Nothobranchius rachovii, has been used. A progressive and sequential CS breakdown has been described for the last 22 d of life of N. rachovii ( 7% of total life), suffering a general RAR impairment mainly reflected by changes in phase regularity, complexity, amplitude and the ability to stay synchronized to the LD cycle. Also, an equation of days remaining of life, based on the RAR description, has been calculated and proposed as a tool to identify close-to-death individuals which could be subjected to an adequate restoring treatment to enhance the CS function and improve their well-being.
- PublicationEmbargoEffects of cadmium on locomotor activity rhythms of the amphipod Gammarus aequicauda(Springer, 2011-04) Sánchez Morillo-Velarde, Mª Piedad; Lloret, J.; Marín, A.; Sánche Vázquez, F. J.; Biología Celular e HistologíaBehavioural responses are linked to complex biochemical and physiologic changes and may act as sensitive indicators of the sublethal effects of pollutants. This article investigates changes in the locomotor activity rhythms of the amphipod Gammarus aequicauda exposed to cadmium (Cd) as a model to study the effect of pollutants on an ecologically important species. Under a 12:12 h light-to-dark cycle, G. aequicauda showed a strict nocturnal rhythm, with 90.2 ± 0.4% of their total daily activity occurring during the night. Under constant darkness, circadian rhythms persisted for 10 days, with a mean periodicity of 24.32 h, thus confirming endogenous control. Exposure to sublethal concentrations of Cd (0.16, 0.20, 0.24, and 0.28 mg l−1) did not change the nocturnal activity patterns of G. aequicauda, although their swimming activity during the night was significantly decreased by exposure to concentrations of 0.24 and 0.28 mg Cd l−1. In conclusion, locomotor activity bioassays using the amphipod G. aequicauda appeared to be a sensitive indicator of Cd contamination, and sensitivity and tolerance to Cd in short-term bioassays may depend on the time of the day tests are carried out. These results provide further support for the idea that behavioural end points in amphipods are useful indicators of pollutant exposure and that future studies should take circadian rhythms into consideration.
- PublicationOpen AccessFeeding entrainment of food-anticipatory activity and per1 expression in the brain and liver of zebrafish under different lighting and feeding conditions(Taylor and Francis Group [Commercial Publisher], 2010) López Olmeda, José Fernando; Tartaglione, Erika; Iglesia, Horacio de la; Sánchez Vázquez, Francisco Javier; FisiologíaFood provided on a periodic basis can act as a potent synchronizer, being a stronger zeitgeber than light for peripheral oscillators in mammals. In fish, however, little is known about the influence of feeding time on the circadian pacemaker and the relationship between central and peripheral oscillators. The aim of this research was to investigate the influence of mealtime on the activity rhythms, and on central (brain) and peripheral (liver) oscillators in zebrafish. The authors tested different feeding times under a light-dark (LD) cycle and the endogenous origin of food- anticipatory activity (FAA) by feeding zebrafish at a fixed time under constant bright- light conditions (LL). The authors then measured locomotor activity and the expression of the clock gene per1 in animals under a LD cycle and fed at random times during the light phase, with restricted feeding at the mid-light phase (ML) or with restricted feeding during the mid-dark phase (MD). Finally, the authors measured locomotor activity and per1 expression in fish maintained under LL under either random feeding or scheduled feeding. Zebrafish displayed FAA in all the groups fed at a fixed time but not when feeding was randomly scheduled. Under LL, fish entrainment persisted, and when released under fasting conditions FAA free-run with a circa-24-h period. The expression of per1 in the brain of fish under LD showed a daily rhythm with the acrophase (peak time) at the end of the dark phase regardless of feeding schedule. This brain rhythm disappeared in LL fish under both random feeding and scheduled feeding. Feeding at MD advanced the phase of per1 in the liver by 7 h compared with the ML-fed group phase (23:54 versus 07:23 h, respectively). In addition, under LL scheduled feeding entrained the rhythms of per1 expression in the liver. This study reveals for the first time that scheduled feeding entrains peripheral oscillators in a fish species, zebrafish, which is a powerful model widely used for molecular genetics and for the study of basic clock mechanisms of the vertebrate circadian system.
- PublicationOpen AccessFeeding entrainment of locomotor activity rhythms, digestive enzymes and neuroendocrine factors in goldfish(2007) Vera, L.M.; De Pedro, N.; Gómez Milán, E.; Delgado, M.J.; Sánchez Muros, M.J.; Madrid, J.A.; Sánchez Vázquez, F.J.; FisiologíaL.M. VERA, N. DE PEDRO, E. GÓMEZ-MILÁN, M.J. DELGADO, M.J. SÁNCHEZ MUROS, J.A. MADRID, F.J. SÁNCHEZ-VÁZQUEZ. Feeding entrainment of locomotor activity, digestive enzymes and neuroendocrine factors in goldfish. PHYSIOL BEHAV 90 (2-3) 518-524, 2007. The existence of food anticipatory activity (FAA) in animals subjected to daily feeding schedules seems to be mediated by a feeding-entrainable oscillator (FEO). Such an FEO may help in anticipating meal time and so optimizing food acquisition and nutrient utilization. In this study we investigated the existence of FAA and whether digestive enzymes, plasma cortisol, hypothalamic NPY and gastrointestinal tract (GIT) and plasma melatonin were entrained by periodic feeding in goldfish. We observed that periodically fed goldfish showed FAA in locomotor activity as well as in amylase and NPY. Alkaline protease and GIT melatonin were higher after feeding, whereas plasma cortisol levels were reduced. Plasma melatonin remained unmodified before and after meal time. These results suggested that scheduled feeding entrained both behavioral and certain physiological patterns in goldfish, FAA being of adaptive value to anticipate a meal and prepare the digestive physiology of fish.
- PublicationOpen AccessInfluence of light intensity on plasma melatonin and locomotor activity rhythms in tench(2005) Vera, L.M.; López Olmeda, J.F.; Bayarri, M.J.; Madrid, J.A.; Sánchez Vázquez, F.J.; FisiologíaMelatonin production by the pineal organ is influenced by light intensity, as has been described in most vertebrate species, in which melatonin is considered a synchronizer of circadian rhythms. In the case of tench, strict nocturnal activity rhythms have been described although the role of melatonin has not been clarified. In this study we investigated daily activity and melatonin rhythms under 12:12 light-dark (LD) conditions with two different light intensities (58.6 and 1091µW/cm2 ), and the effect of one hour broad spectrum white light pulses of different intensities (3.3, 5.3, 10.5, 1091.4 µW/cm2 ) applied at mid darkness (MD) on nocturnal circulating melatonin. The results showed that plasma melatonin in tench under LD 12:12 and high light conditions displayed a rhythmic variation, where values at MD (255.8 ± 65.9 pg/ml) were higher than at mid light (ML) (70.7 ± 31.9 pg/ml). Such a difference between MD and ML values was reduced in animals exposed to LD 12:12 and low light intensity. The application of one hour light pulses at MD lowered plasma melatonin to 111.6 ± 3.2 pg/ml (in the 3.3-10.5 µW/cm2 range) and to 61.8 ± 18.3 pg/ml (with the 1091.4 µW/cm2 light pulse) and totally suppressed nocturnal locomotor activity. These results showed that melatonin rhythms persisted in tench exposed to low light intensity although the amplitude of the rhythm is affected. In addition, it was observed that light pulses applied at MD affected plasma melatonin content and locomotor activity. Such a low threshold suggests that the melatonin system is capable of transducing light even under dim conditions, which may be used by this nocturnal fish to synchronize to weak night light signals (e.g. moonlight cycles)
- PublicationOpen AccessLight and feeding entrainment of the molecular circadian clock in a marine teleost (Sparus aurata)(Taylor and Francis Group, 2013-05-20) Vera Andujar, Luisa María; Negrini, P.; Zagatti, C.; Frigato, E.; Sánchez-Vázquez, F.J.; Bertolucci, C.; FisiologíaDaily light and feeding cycles act as powerful synchronisers of circadian rhythmicity. Ultimately, these external cues entrain the expression of clock genes, which generate daily rhythmic behavioural and physiological responses in vertebrates. In the present study, we investigated clock genes in a marine teleost (gilthead seabream). Partial cDNAs sequences of key elements from both positive (Bmal1, Clock) and negative (Per2, Cry1) regulatory loops were cloned before studying how feeding time affects the daily rhythms of locomotor activity and clock gene expression in the central (brain) and peripheral (liver) oscillators. To this end, all fish were kept under a light-dark (LD) cycle and were divided into three experimental groups, depending on the time of their daily meal: mid-light (ML), middarkness (MD) or at random times (RD). Finally, the existence of circadian control on gene expression was investigated in the absence of external cues (DD + RD). The behavioural results showed that seabream fed at ML or RD displayed a diurnal activity pattern (>91% of activity during the day), whereas fish fed at MD were nocturnal (89% of activity during the night). Moreover, seabream subjected to regular feeding cycles (ML and MD groups) showed food anticipatory activity (FAA). Regardless of the mealtime the daily rhythm of clock gene expression in the brain peaked close to the light-dark transition in the case of Bmal1 and Clock, and at the beginning of the light phase in the case of Per2 and Cry1, showing the existence of phase delay between the positive and negative elements of the molecular clock. In the liver, however, the acrophases of the daily rhythms differed depending on the feeding regime: the maximum expression of Bmal1 and Clock in the ML and RD groups was in antiphase to the expression pattern observed in the fish fed at MD.Under constant conditions (DD + RD), Per2 and Cry1 showed circadian rhythmicity in the brain, whereas Bmal1, Clock and Per2 did in the liver. Our results indicate that the seabream clock gene expression is endogenously controlled and in liver it is strongly entrained by food signals, rather than by the LD cycle, and that scheduled feeding can shift the phase of the daily rhythm of clock gene expression in a peripheral organ (liver) without changing the phase of these rhythms in a central oscillator (brain), suggesting uncoupling of the light-entrainable oscillator (LEO) from the food-entrainable oscillator (FEO). These findings provide the basis and new tools for improving our knowledge of the circadian system and entraining pathways of this fish species, which is of great interest for the Mediterranean aquaculture.