29 resultados para Neotropical primate
Resumo:
The circadian system consists of multiple oscillators organized hierarchically, with the suprachiasmatic nucleus (SCN) as the master oscillator to mammalians. There are lots of evidences that each SCN cell is an oscillator and that entrainment depends upon coupling degree between them. Knowledge of the mechanism of coupling between the SCN cells is essential for understanding entrainment and expression of circadian rhythms, and thus promote the development of new treatments for circadian rhythmicity disorders, which may cause various diseases. Some authors suggest that the dissociation model of circadian rhythm activity of rats under T22, period near the limit of synchronization, is a good model to induce internal desynchronization, and in this way, enhance knowledge about the coupling mechanism. So, in order to evaluate the pattern of the motor activity circadian rhythm of marmosets, Callithrix jacchus, in light-dark cycles at the lower limit of entrainment, two experiments were conducted: 1) 6 adult females were submitted to the LD symmetric cycles T21, T22 and T21.5 for 60, 35 and 48 days, respectively; 2) 4 male and 4 female adults were subjected to T21 for 24 days followed by 18 days of LL, and then back to T21 for 24 days followed by 14 days of LL. Vocalizations of all animals and motor activity of each one of them were continuously recorded throughout the experiments, but the vocalizations were recorded only in Experiment 1. Under the Ts shorter than 24 h, two simultaneous circadian components appeared in motor activity, one with the same period of LD cycle, named light-entrained component, and the other in free-running, named non-light-entrained component. Both components were displayed for all the animals in T21, five animals (83.3%) in T21.5 and two animals (33.3%) in T22. For vocalizations both components were observed under the three Ts. Due to the different characteristics of these components we suggest that dissociation is result of partial synchronization to the LD cycle, wherein at least one group oscillator is synchronized to the LD by relative coordination and masking processes, while at least another group of oscillators is in free-running, but also under the influence of masking by the LD. As the T21 h was the only cycle able to promote the emergence of both circadian components in circadian rhythms of all Callithrix jacchus, this was then considered the lower entrainment limit of LD cycle promoter of dissociation in circadian rhythmicity of this species, and then suggested as a non-human primate model for forced desynchronization
Resumo:
The pregeniculate nucleus (PGN) of the primate s thalamus is an agglomerate neuronal having a cap shaped located dorsomedially to the main relay visual information to the cerebral cortex, the dorsal lateral geniculate nucleus (GLD). Several cytoarchitectonic, neurochemical and retinal projections studies have pointed PGN as a structure homologous to intergeniculate leaflet (IGL) of rodents. The IGL receives retinal terminals and appears to be involved in the integration of photic and non-photic information relaying them, through geniculo-hypothalamic tract (TGH), to the main circadian oscillator in mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus. Thus, the IGL participates in the control of the biological rhythm by modulating the activity of the SCN. Pharmacological and IGL injury studies conclude that it is critical in the processing of non-photic information which is transmitted to the SCN. Other studies have found that especially neurons immunoreactive to neuropeptide Y (NPY) respond to this type of stimulation, determined by its colocation with the FOS protein. Has not been determined if the PGN responds, expressing the FOS protein, to the non-photic stimulus nor the neurochemical nature of these cells. Thus, we apply a dark pulse in the specifics circadian phases and analyze the pattern of expression of FOS protein in PGN of the marmoset (Callithrix jacchus). We found that in all animals analyzed the FOS expression was higher in the experimental than in the control group. There was a higher expression of FOS when the dark pulse was applied during the subjective day between the groups. Still, a subregion of the PGN, known by immunoreactive to NPY, had a greater number of FOS-positive cells in relation to his other just close dorsal region. Our data corroborate the theory that the PGN and IGL are homologous structures that were anatomically modified during the evolutionary process, but kept its main neurochemical and functional characteristics. However, injury and hodological studies are still needed for a more accurate conclusion
Resumo:
The principal zeitgeber for most of species is the light-dark photocycle (LD), though other environment factors as food availability, temperature and social cues may act. Daily adjustment of the circadian pacemaker may result from integration of environmental photic and non-photic cues with homeostatic cues. Characterization of non-photic effects on circadian timing system in diurnal mammals is scarce in relation to nocturnal, especially for ecologically significant cues. Thus, we analyzed the effect of conspecific vocalizations and darkness on circadian activity rhythm (CAR) in the diurnal primate Callithirx jacchus. With this objective 7 male adults were isolated in a room with controlled illumination, temperature (26,8 ± 0,2°C) and humidity (81,6 ± 3,6%), and partial acoustic isolation. Initially they were under LD 12:12 (~300:2 lux), and subsequently under constant illumination (~2 lux). Two pulses of conspecific vocalizations were applied in total darkness, separated by 22 days, at 7:30 h (external time) during 1 h. They induced phase delays at circadian times (CTs) 1 and 10 and predominantly phase advances at CTs 9 and 15. After that, two dark pulses were applied, separated by 14 days, during 1 h at 7:30 h (external time). These pulses induced phase delays at CTs 2, 3 and 18, predominantly phase advances at CTs 8, 10 and 19, and no change at CT 14. However, marmosets CAR showed oscillations in endogenous period and active phase duration influenced by vocalizations from animals outside the experimental room, which interfered on the phase responses to pulses. Furthermore, social masking and relative coordination with colony were observed. Therefore, phase responses obtained in this work cannot be attributed only to pulses. Afterwards, pulses of conspecific vocalizations were applied in total darkness at 19:00 h (external time), during 1 h for 5 consecutive days, and after 21 days, for 30 consecutive days, on attempt to synchronize the CAR. No animal was synchronized by these daily pulses, although oscillations in endogenous period were observed for all. This result may be due to habituation. Other possibility is the absence of social significance of the vocalizations for the animals due to random reproduction, since each vocalization has a function that could be lost by a mixture of sounds. In conclusion, conspecific vocalizations induce social masking and relative coordination in marmosets CAR, acting as weak zeitgeber
Resumo:
Most of ontogenetic studies on circadian timing system have been developed on infants, adults and elderly. The puberty has not been a stage of life few studied, except for researches in human adolescents, that presents phase delay in sleep-wake cycle. However, few studies have focused on the basis of this circadian change due to methodological difficulties. Thus, an animal model to study the sleep-wake cycle at puberty is essential. In the common marmoset, a social primate, the circadian activity periodicity stabilizes around 4 months (juvenile stage) and the 8h period component has a seasonal variation. Puberty stage of this species begins near the 8th month of age in males and near the 7th month in females with 7 months of duration. With the aim to characterize the circadian motor activity rhythm during puberty in marmosets (Callithrix jacchus) the motor activity was continuous registered by actiwatches in 6 animals between 5-12 months. Since the social factor influence the behavior of this specie, behavioral observations were realized in 30 minutes windows twice/week to a general evaluation of the influence social interactions dynamic across experiment. Determination of puberty onset was done by fecal progesterone and estrogens in females, and androgens in males. From the analysis of the multiple regression test was selected a model that evaluate age and seasonal variables effect on the activity rhythm according to the higher explanation coefficient. The total activity was the only parameter influenced by age. Moreover, the activity onset was the parameter more explained by the model, and the sunrise was the factor that most influenced it. After the puberty onset, 2 dyads advanced the activity onset. The activity total decreased in 1 dyad and increased in 2 dyads. This increase may be related to the birth of infants in these families. The motor activity circadian component stabilized later in 1 dyad, coinciding with the puberty onset of these animals, while bimodality, caused by the 8 h component, was modulated by seasonality. The agonistic behavior was not evaluated due to reduced number of events. There were changes across ages in affiliative behavior of contact in 1 dyad, grooming done in 1 animal and grooming received in 2 animals. Although there is evidence of puberty effect on the activity motor rhythm, the photoperiodic fluctuations influenced the rhythm. Therefore is not possible to affirm if the puberty modulate the activity rhythm in marmosets
Resumo:
In rodents, the suprachiasmatic nucleus (SCN) and the intergeniculate leaflet (IGL) are the main components of the circadian system. The SCN is considerate the site of an endogenous biological clock because can to generate rhythm and to synchronize to the environmental cues (zeitgebers) and IGL has been related as one of the main areas that modulate the action of SCN. Both receive projections of ganglion cells of retina and this projection to SCN is called retinohypothalamic tract (RHT). Moreover, the IGL is connected with SCN through of geniculohypothalamic tract (GHT). In primates (include humans) was not still demonstrated the presence of a homologous structure to the IGL. It is believed that the pregeniculate nucleus (PGN) can be the answer, but nothing it was still proven. Trying to answer that question, the objective of our study is to do a comparative analysis among PGN and IGL through of techniques immunohystochemicals, neural tracers and FOS expression after dark pulses. For this, we used as experimental model a primate of the new world, the common marmoset (Callithrix jacchus). Ours results may contribute to the elucidation of this lacuna in the circadian system once that the IGL is responsible for the transmission of nonphotic information to SCN and participate in the integration between photic and nonphotic stimulus to adjust the function of the SCN. In this way to find a same structure in primates represent an important achieve in the understanding of the biological rhythms in those animals
Resumo:
The auditory system is composed by a set of relays from the outer ear to the cerebral cortex. In mammals, the central auditory system is composed by cochlear nuclei, superior olivary complex, inferior colliculus and medial geniculate body. In this study, the auditory rombencephalic centers, the cochlear nuclear complex and the superior olivary complex were evaluated from the cytoarchitecture and neurochemical aspects, thorough Nissl staining and immunohistochemical techniques to reveal specific neuron nuclear protein (NeuN), glutamate (Glu), glutamic acid decarboxilase (GAD), enkephalin (ENK), serotonin (5-HT), choline acetyltransferase (ChAT) and calcium-binding proteins calbindin (CB), calretinin (CR), and parvalbumin (PV). The common marmoset (Callithrix jacchus), a little native primate of the Brazilian atlantic forest was used as an experimental animal. As results, it was noted that the cochlear nuclear complex is composed by anteroventral, posteroventral and dorsal nuclei, and the superior olivary complex is constituted by the lateral and medial superior olivary nuclei and the trapezoid body nucleus. Glu, GAD, ENK, ChAT, CB, CR, PV-immunoreactive cells, fibers and terminals besides besides only 5-HT terminals were found unhomogeneously in all nuclei, of both complex. The emerging data are discussed in a comparative and functional context, and represent an important contribution to knowledge of the central auditory pathways in the common marmoset, and then in primates
Resumo:
The retinal projections in mammals usually reach, classically, three major functional systems: the primary visual system, the accessory optic system, and the circadian timing system. But the retinal projections also reach areas classically considered non-visual, one of which groups the neurons of the zona incerta (ZI), target this study. The primary visual system includes thalamic lateral geniculate complex is formed by the dorsal lateral geniculate nucleus, intergeniculate leaflet and the ventral lateral geniculate nucleus and other Components. The accessory optic system is composed of the small nuclei: nuclei terminal dorsal, lateral, medial and the interstitial nucleus of the superior posterior fasciculus. These nuclei are involved in visuo-motor activities. The circadian timing system is comprised of the suprachiasmatic nucleus of the hypothalamus, that act as master circadian pacemaker, entraining pathways and efferents pathways to the efectors, and the intergeniculate leaflet, that seems to act as a modulator of the pacemaker. The retinal projections too reach classically considered non-visual areas, including the zona incerta. This region is localized in the ventral thalamus and has been implicated in various functional properties including nociceptive and somatosensory processing, motor response, sociosexual behaviour, feeding and drinking, in symptoms of neurodegenerative diseases, arousal and attention. It also displays connection with several areas of central nervous system. The aim of this study was characterize the retinal projection in the zona incerta of Callithrix jacchus (sagüi), a primate of the New World through the anterograde axonal transport of the cholera toxin subunit b and analyze the citoarchicteture using Nissl and NeuN, and neurochemical substances such as serotonin, GABA, VIP, VP, GFAP and binding-calcium proteins. The zona incerta showed a different division of the literature in citoarquitetura, both by means of Nissl as neurochemical by NeuN, with a subdivision ventrolateral and dorsomedial. The neurochemical to the other substances corroborate with this subdivision. The GFAP was almost completely negative for the zona incerta, result non evidenced in previous studies yet. The 16 retinal projection in sagüi, unlike other primates and rodents, reached the caudal portion only. This work helps to make further studies are conducted based on this subdivision and the localization of the neurochemical substances associated with possible behaviors that the zona incerta is involved
Resumo:
Caffeine is considered the most consumed psychostimulant in the world, presenting several central and peripheral effects. In the Central Nervous System the major effect occur by its antagonistic activity at the A1 and A2a subtypes of the adenosine receptors. These receptors are responsible for the slow-wave sleep induction, and their binding, caused by the consumption of foods and beverages that contain caffeine, cause behaviors like increase of alertness, mood and locomotion. The effects of caffeine on memory are still discussed because of the diversity of experimental protocols. Also, it does not have the same effects on all stages of the processing of memory - acquisition, consolidation and recall. Thus, using the marmoset (Callitrhix jacchus) as subject, we aim to evaluate the effects of caffeine on the memory of this primate through the conditioned place preference paradigm, where the animal selects a context by presence of food. This cognitive task consists of five phases. The first phase was two sessions of pre-exposure, in which they were evaluated for preference for any compartment of the apparatus. Then, we proceeded the training, conditioning the animals to the food-present context for 8 days. Then, there was administration of caffeine or placebo (10mg/kg) for 8 consecutive days, during the pre-sleep phase, where the 20 animals were distributed in two groups: placebo and repeated. The forth phase was one day of retraining, a re-exposure of the apparatus to the marmosets followed by the administration of caffeine (for the repeated group and a new group called abstinence) or placebo (for placebo and abstinence groups). Finally, was the test where we evaluated if the subjects learned where the food was present. Moreover, in this work we evaluate the existence of differences between females and males on the task, and the locomotor activity for the experimental groups. The results showed that in the pre-exposure phase the animals were habituated on the apparatus and did not present differences for any contexts. In training, they were able to learn the conditioning task, independent of gender. For the retraining, the two groups exhibited more interactions in rewarded context than that in non-rewarded context. Nevertheless, in the locomotor activity, the repeated group moved similarly in contact with the apparatus and outside of it. In the other hand, the animals of the placebo group moved more when in contact with the apparatus. In the test phase, the marmosets under influence of caffeine presented an increase in the locomotor activity when compared with the placebo group, corroborating works that show this increase in locomotion. In the learning evaluation, the continuous and abstinence groups had a bad performance in the task in relation to the placebo and acute groups. This suggests that the prolonged administration of caffeine disrupts the memories because it affected sleep, which is largely responsible offline processing of memories
Resumo:
The thalamus plays an important role in the sensorial processing information, in this particular case, the visual information. Several neuronal groups have been characterized as conductors and processors of important sensorial information to the cerebral cortex. The lateral geniculate complex is one to them, and appears as a group very studied once it is responsible, in almost all totality, for the processing of visual information. Among the nuclei that constitute the lateral geniculate complex we highlight the dorsal lateral geniculate nucleus of the thalamus (DLG), the main thalamic relay for the visual information. This nucleus is located rostral and lateral to medial geniculate nucleus and ventral to thalamic pulvinar nucleus in most of the mammals. In the primates humans and non-humans, it presents as a laminate structure, arranged in layers, when observed in coronal sections. The objective of this work was to do a mapping of the retinal projections and a citoarchictetonic and neurochemical characterization of DLG in the marmoset (Callithrix jacchus), a New World primate. The retinal projections were traced by anterograde transport of subunit b of cholera toxin (CTb), the citoarchicteture was described by Nissl method, and to neurochemical characterization immunohistochemicals technical were used to examine the main neurotransmitters and neuroatives substances present in this neural center. In DGL of marmoset thalamus, in coronal sections labeled by Nissl method, was possible to visualize the division of this nucleus in four layers divided in two portions: magnocellular and parvocellular. The retinal projections were present being visualized fibers and terminals immunorreactives to CTb (IR-CTb) in the DLG ipsilateral and contralateral. And through the immunohistochemicals techniques was observed that DLG contain cells, fibers and/or terminals immunoreactives against neuronal nuclear protein, subunits of AMPA 15 glutamate receptors (GluR1, GluR2/3, GluR4), choline acetyltransferase, serotonin, glutamic acid decarboxylase, binding calcium proteins (calbindin, parvalbumin and calretinin), vasopressin, vasoactive intestinal polypeptide, and an astrocyte protein, glial fibrillary acidic protein.
Resumo:
The parabrachial complex (PB) is an area of the brainstem responsible for the processing and transmission of essential physiologic information for the survival of the organisms. This region is subdivided in approximately nine subregions, considering morphology, cytoarchitectural and functional characteristic. Its neurons have an extensive network of connections with other regions of the nervous system. The objective in this work was to map the retinal projection to the PB and make a citoarchitectonic and neurochemical characterization of this region in the common marmoset (Callithrix jacchus), a primate of the New World. The retinal projections were mapped by anterograde transport of the choleric toxin subunit b (CTb). The citoarchitecture was described through the Nissl method, and the neurochemical characterization was made through immunohistochemical technique to the some neurotransmitters and neuroactives substances present in this neural center. In marmoset PB, in the coronal sections labeled by Nissl method, we found a similar pattern to that evidenced in other animal species. The immunoreactivity against CTb was verified in the PBMv in fibers/terminal, characterizing such as retinal innervations in this area. The immunohistochemical technique reveled that the PB contain cells, fibers and/or terminals immunoreactives to the neuronal nuclear protein, Choline acetyl transferase, nitric oxide synthase, serotonin, enkephalin, substance P, Calcium-binding proteins (calbindin, calretinin e parvalbumin), and glial fibrillary acidic protein. The histochemical technique reveled cells and fibers NADPH-diaphorase reactive. Each one of those substances presented a characteristic pattern of demarcation in PB, and some serve as specific markers of subregions
Resumo:
Considering the constant environmental changes, the ability to introduce new food items in the diet is crucial to omnivore animal survival. For optimal nourishment and lessening of intoxication risks, the animals must detect signs that indicate which items are adequate for their intake. We investigate some factors that interfere in the responses to non familiar food, modulating their neophobic behavior, of marmosets Callithrix jacchus, an omnivore and generalist primate, native to Northeast Brazil, known for being cautious in ingesting not known food. We analyzed the influence of food taste (sweet or salty), pregnancy and sex in feeding behavior and neophobic responses in these animals. 10 captive females were first selected, 5 of them being then pregnant. The females, pregnant or not, ate more when presented to the sweet items than to the salty ones. Pregnant females, however, themselves were less neophobic to both tastes, being also strongly neophilic to the sweets. We verified then the influence of nourishment during pregnancy on young males and females post natal feeding behavior. We observed 10 young divided in two groups, one whose mother ate that food item during pregnancy and one whose mother had no contact to it. In the first group that food was more easily accepted by the young, suggesting that neofobia and feeding behavior had a pre natal influence. Female young also ingested more food and were less neophobic than males, a difference already observed in behavior of adults of these specie. These results suggest that the low neophobic behavior to sweet food showed by females can be adaptive, and might have bestowed more fitness to those who presented it
Resumo:
The suprachiasmatic nucleus (SCN) of the anterior hypothalamus, together with the intergeniculate leaflet (IGL) of the thalamus are considered the central components of the circadian timing system (CTS) of mammals. This system is responsible for the generation and regulation of circadian rhythms by establishing a temporal organization of physiological processes and behaviors. The neuronal specific nuclear protein (NeuN) has been widely used as a neuronal marker in several studies. Since glial fibrillary acidic protein (GFAP) is a component of intermediate filaments found in the cytoplasm of astrocytes and is commonly used as a specific marker for these cells. This study aims to identify, in the marmoset, the NeuN immunoreactive neurons and glial cells immunoreactive to GFAP, as well as map the major route of photic synchronization of the STC, retinohypothalamic tract (RHT), and identify the indirect pathway to the SCN and pregeniculate nucleus (PGN) - structure homologous to IGL rodents, using immunohistochemical and cytoarchitectonic techniques. Observed in SCN the presence of neurons immunoreactive to NeuN and terminals immunoreactive subunit b of cholera toxin (CTb), neuropeptide Y (NPY) and serotonin (5- HT). In the PGN noted the presence of the NeuN and NPY immunoreactive neurons and the immunoreactive terminals CTb and 5-HT. Astrocytes are present throughout the extent of the SCN and the PGN this New World primate
Resumo:
As social animals, primates use different sensory modalities (acoustic, chemical, tactile and visual) to convey information about social and sexual status to conspecifics. Among these modalities, visual signals are widely used, especially color signals, since primates are the mammalian group that displays the greatest variety of colors in their skin and fur. Studies with Old World primate species suggest that hormonal variations are related to variations in the colors of individual faces and genitals. Therefore, chromatic cues can be used by conspecifics to identify the reproductive condition of an individual. To date, studies with the same approach are unknown for New World species. However, behavioral and physiological studies suggest that different New World primate species seem to perceive reproductive conditions such as the timing of female conception and gestation. Thus, in this study, our aim was to: i) identify whether there are chromatic cues on the skin of female common marmosets, (Callithrix jacchus) that indicate their reproductive condition; ii) define whether this chromatic variation can be perceived by all visual phenotypes known in this species; iii) identify if these chromatic cues can be perceived under different light intensity levels (dim, intermediate and high). For this, we selected 13 female common marmosets in four distinct reproductive conditions: pregnant female preceding parturition, postpartum mothers, noncycling and cycling females. The coloration of the skin in genital and thigh areas in females was measured using a spectrophotometer. Using mathematical models of visual perception, we calculated the values of quantum catch for each photoreceptor type known in this species, the visual opponency channels and color contrast between those body spots. Our results indicate the occurance of chromatic variations in the genital area during the weeks that precede and follow parturition, forming a U-pattern of variation perceptible to males and females in natural conditions of low and high luminosity. Furthermore, we observed distinct color patterns in the genital skin of pregnant and cycling females that indicate their reproductive conditions. Finally, we present evidence of color contrast in noncycling females that is higher than that of pregnant ones. This study suggests that there is a chromatic xii variation in the genital skin of females that can be perceived by conspecifics and that may be related to hormonal changes typical of pregnancy and the ovarian cycle
Resumo:
Gasteroid fungi include several distinct lineages of basidiomycetes that were grouped by presenting some striking features in common like angiocarpic development and passive release of basidiospores. For a long period these fungi were accomodate in Gasteromycetes class. However, biochemistry and molecular studies showed the polyphyly of this group and curriently this class lies devoid of taxonomic value. These organisms influence the ecology of the various biomes, however, are poorly studied and knowledge of their diversity in neotropical ecosystems remains insufficient, despite studies that have been developed in recent years. The Brazilian semiarid region has many areas with an unexplored mycobiota. Ceará State has many areas of extreme biological importance and for this study three protected areas were chosen: Área de Proteção Ambiental da Serra da Ibiapaba, Parque Nacional de Ubajara and Área de Proteção Ambiental de Baturité. Therefore, the aim of this study was to inventory gasteroid fungi ocorring in these three areas in the semiarid region of Ceará. The expeditions, herborization and analysis of specimes were based in traditional methodology used to identify gasteroid fungi. Were identified 16 species belong to 5 families: Agaricaceae, Clathraceae, Geastraceae, Nidulariceae and Phallaceae. Morganella nuda Alfredo & Baseia is recorded for the second time in the world, Blumenavia angolensis (Welw. & Curr) Dring and Mutinus elegans (Mont.) E. Fisch. corresponds to a first record in the Brazilian Northeastern. Except for Abrachium floriforme (Baseia & Calonge) Baseia & T.S. Cabral and Geastrum lloydianum Rick, all remaining species are new records for Ceará, increasing the list of gasteroid fungi in the region of 3 for 17 species. Identified species were deposited in the collection of the Herbarium of Universidade Federal do Rio Grande do Norte. Although these areas have proved conducive to the study of gasteroid fungi, more efforts are still needed to increase knowledge of these fungi in the region