Navegando por Palavras-chave "Circadian rhythms"
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- ItemAcesso aberto (Open Access)Análise da distribuição da frequência de polimorfismos em genes relógio, nos grupos étnicos asiático e caucasiano que compõem a população brasileira(Universidade Federal de São Paulo (UNIFESP), 2010-04-28) Barbosa, Ana Alves [UNIFESP]; Pedrazzoli, Mario [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)The Period 3 and Clock genes are important components of the mammalian molecular circadian system. Studies have shown association between polymorphisms in these clock genes and circadian phenotypes in different populations. Nevertheless, differences in the pattern of allele frequency and genotyping distribution are systematically observed in studies with different ethnic groups. To investigate and compare the pattern of distribution in a sample of Asian and Caucasian populations living in Brazil, we evaluated two well-studied polymorphisms in the clock genes: a variable number of tandem repeats (VNTR) in PER3 and a single nucleotide polymorphism (SNP) in CLOCK. The aim of this investigation was to search for clues about human evolutionary processes related to circadian rhythms. We selected 109 Asian and 135 Caucasian descendants. The frequencies of the shorter allele (4 repeats) in the PER3 gene and the T allele in the CLOCK gene among Asians (0.86 and 0.84, respectively) were significantly higher than among Caucasians (0.69 and 0.71, respectively). Our results directly confirmed the different distribution of these polymorphisms between the Asian and Caucasian ethnic groups. Given the genetic differences found between groups, two points became evident: first, ethnic variations may have implications for the interpretation of results in circadian rhythm association studies, and second, the question may be raised about which evolutionary conditions shaped these genetic clock variations.
- ItemAcesso aberto (Open Access)Do Caucasian and Asian clocks tick differently?(Associação Brasileira de Divulgação Científica, 2010-01-01) Barbosa, Ana Alves [UNIFESP]; Pedrazzoli, Mario [UNIFESP]; Koike, Bruna Del Vechio [UNIFESP]; Tufik, Sergio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)The Period 3 and Clock genes are important components of the mammalian molecular circadian system. Studies have shown association between polymorphisms in these clock genes and circadian phenotypes in different populations. Nevertheless, differences in the pattern of allele frequency and genotyping distribution are systematically observed in studies with different ethnic groups. To investigate and compare the pattern of distribution in a sample of Asian and Caucasian populations living in Brazil, we evaluated two well-studied polymorphisms in the clock genes: a variable number of tandem repeats (VNTR) in PER3 and a single nucleotide polymorphism (SNP) in CLOCK. The aim of this investigation was to search for clues about human evolutionary processes related to circadian rhythms. We selected 109 Asian and 135 Caucasian descendants. The frequencies of the shorter allele (4 repeats) in the PER3 gene and the T allele in the CLOCK gene among Asians (0.86 and 0.84, respectively) were significantly higher than among Caucasians (0.69 and 0.71, respectively). Our results directly confirmed the different distribution of these polymorphisms between the Asian and Caucasian ethnic groups. Given the genetic differences found between groups, two points became evident: first, ethnic variations may have implications for the interpretation of results in circadian rhythm association studies, and second, the question may be raised about which evolutionary conditions shaped these genetic clock variations.
- ItemSomente MetadadadosDoes the lunar phase have an effect on sudden unexpected death in epilepsy?(Elsevier B.V., 2009-02-01) Terra-Bustamante, Vera C.; Scorza, Carla A. [UNIFESP]; Albuquerque, Marly de [UNIFESP]; Sakamoto, Americo C.; Machado, Helio R.; Arida, Ricardo M. [UNIFESP]; Cavalheiro, Esper A. [UNIFESP]; Scorza, Fulvio A. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)The incidence of sudden unexpected death in epilepsy (SUDEP) in Our epilepsy unit over an 8-year period was analyzed to determine a possible association between phase of the moon and SUDEP. Analysis revealed that the number of SUDEPs was highest in full moon (70%), followed by waxing moon (20%) and new moon (10%). No SUDEPs Occurred during the waning cycle. These preliminary findings suggest that the full moon appears to correlate with SUDEP. (C) 2008 Elsevier Inc. All rights reserved.
- ItemSomente MetadadadosEffects of long-term continuous exposure to light on memory and anxiety in mice(Elsevier B.V., 2005-09-15) Castro, Juliana Pedroso Moraes Vilela de [UNIFESP]; Frussa-Filho, Roberto [UNIFESP]; Fukushiro, Daniela Fukue [UNIFESP]; Chinen, Cibele Cristina [UNIFESP]; Abílio, Vanessa Costhek [UNIFESP]; Silva, Regina Helena [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)The studies on the relationship between the light/dark cycle and memory function mostly used protocols of acute disruption of the circadian rhythm. the aim of the present study is to verify the effects of long-term continuous exposure to light on memory, anxiety and motor parameters of mice tested in the plus-maze discriminative avoidance task. Mice were conditioned to choose between the two enclosed arms (one aversive and one non-aversive) while avoiding the open arms of a modified elevated plus-maze apparatus. Memory was evaluated by the time spent in the aversive enclosed arm, anxiety was evaluated by the time spent in the open arms and locomotor behavior was evaluated by number of entries in the arms of the maze. the results showed that long-term (35-42 days) continuous light exposure did not modify memory or anxiety parameters but increased locomotor activity. While the increase in locomotor behavior is in line with previous studies, the unexpected absence of alterations in memory and anxiety (reported to be influenced by the circadian rhythm) is discussed. (c) 2005 Elsevier Inc. All rights reserved.
- ItemSomente MetadadadosNeonatal exposure to constant light prevents anhedonia-like behavior induced by constant light exposure in adulthood(Elsevier B.V., 2011-09-12) Martynhak, Bruno J.; Correia, Diego; Morais, Livia H.; Araujo, Paula [UNIFESP]; Andersen, Monica L. [UNIFESP]; Lima, Marcelo M. S.; Louzada, Fernando M.; Andreatini, Roberto; Univ Fed Parana; Universidade Federal de São Paulo (UNIFESP)Depressive episodes are associated with disturbances in circadian rhythms, and constant illumination has been reported to induce depressive-like behavior in rodents. Rats kept in constant darkness express the endogenous circadian rhythm, and most animals under constant light conditions lose circadian locomotor rhythmicity. Exposure to constant light in rats during lactation was reported to prevent this loss of circadian rhythm in adulthood. Thus, the aim of the present study was to verify whether exposure to constant light during lactation prevents anhedonia-like behavior induced by constant light in adult rats. in experiment 1, we replicated the anhedonia-like effects of constant light in adult male rats. We showed that this effect is reversed by imipramine treatment in the drinking water. in experiment 2, we subjected rats to constant darkness (neonatal-DD), constant light (neonatal-LL) or to normal light/dark cycle (neonatal-LD) during the neonatal phase and evaluated them after constant light exposure in adulthood. the group exposed to constant light during the neonatal phase did not reduce their sucrose preference and exhibited greater locomotor activity than the other groups. the neonatal-DD group exhibited decreased sucrose preference earlier than controls and had higher serum corticosterone concentrations. Prevention of arrhythymicity might protect neonatal-LL rats from anhedonia-like behavior induced by constant light, whereas constant darkness during the neonatal phase rendered the neonatal-DD group more susceptible to depressive-like behavior. These results corroborate with the literature data indicating that circadian disruption may contribute in mood disorders and that early life stress can influence stress responsivity in adulthood. (C) 2011 Elsevier B.V. All rights reserved.