O trabalho é considerado um importante zeitgeber social. Objetivo: O objetivo do presente estudo é avaliar o ritmo social de pacientes adultos dependente de crack, internados na Unidade de Adição/ Unidade Álvaro Alvim do Hospital de Clínicas de Porto Alegre. Método: Participaram da pesquisa 50 pacientes dependentes de crack, internados para desintoxicação e reabilitação, aos quais foram aplicados questionários sócio-demográficos que permitiram conhecer a situação social, de moradia, renda, trabalho e emprego, tratamentos prévios e rede sócio-assistencial dos participantes, questionário para avaliação de indivíduos matutinos e vespertinos, escala breve de avaliação de ritmo social e revisão de prontuário. Resultados: A média de idade da amostra foi de 34,6 anos, 54% solteiros, com maior predominância na religião católica (54,3%). Cerca de 40% dos indivíduos contam com renda familiar mensal de 3 salários mínimos ou mais. Dos indivíduos que estão trabalhando ou em benefício do INSS (60%), 14% desenvolve as suas atividades no comércio, e cerca de 12 % trabalham na construção civil. A média da regularidade das atividades desenvolvidas (HITs) ficou em torno de 5,8 e a média do montante de atividades desenvolvidas (ALIs) foi de 33,8. Não Houve diferença significativa na correlação entre abandono de tratamento. Com relação à ritimicidade (5,8), os pacientes internados apresentaram um alto índice de regularidade, comparados com pessoas sem uso de drogas não internadas (4,2).1. Não foi encontrada relação entre o cronotipo dos participantes e o resultado dos HITs e ALIs. Conclusão: Apesar de ser mencionado o trabalho como um dos principais motivos para abandono de tratamento, os resultados deste trabalho não sustentam esta premissa. A situação de trabalho e a profissão não estão associadas ao abandono prévio de tratamento. Por outro lado, contrariando nossa hipótese inicial, a escolaridade aparece de maneira significativa, sendo evidenciado que quanto maior a escolaridade maior o índice de abandono precoce. A relação entre HITs e ALIs sugere que quanto mais atividades desenvolvidas, maior a regularidade com que elas foram realizadas durante a internação. No entanto, estudos futuros de segmento serão necessários para avaliar a manutenção desta regularidade. / Work is considered an important social zeitgeber. Objective: The aim of this study is describe the social rhythm of adult crack-cocaine users that are hospitalized in the Addiction Treatment Unite of the Hospital of Clinics of Porto Alegre. Method: 50 crack-cocaine users were interviewed after admission for detoxification and rehabilitation. We performed interviews with socio-demographic questionnaires that allowed us to access the social characteristics, housing, income, labor and employment, previous treatments and social assistance network. Also, they answer to a instrument to identify which individuals were morning or evening subjects, the Brief Social Rhythm Scale and chart review were assessed. Results: Mean age of the sample was 34.6 years old, and 54% of individuals reported to be single with predominance in the Catholic religion (54.3%). About 40% of the sample have a monthly family income of three minimum wages or more. Among individuals who are currently working or receive a benefit from Government (60%), 14% develop their activities in trade and 12% work in construction. The average of regularity of activities performed inside the inpatient unit (HITs) was around 5.8 and the average of amount of activities performed inside the inpatient unit (ALIs) was 33.8. There was no significant difference in the correlation between treatment dropout and rhythmicity. Regarding rhythmicity (5.8), hospitalized patients reported high levels of regularity when compared to individuals who were not hospitalized, neither had drug use (4.2) .1 We did not find a correlation between participant’s chronotipes and HITs and ALIs results. Conclusion: Despite work is cited as a major reason for treatment dropout, the results of this study do not support this premise. Work situation and the profession are not associated with prior treatment dropout. Contrary to our initial hypothesis, schooling appears as an important issue because it is significantly associated to early treatment dropout. The relationship between HITs and ALIs suggests that the more activities were developed, the greater the regularity with which they were performed during hospitalization. However, future follow-up studies are needed to evaluate the maintenance of this regularity.

It is well known that 24-hour day-night (light-dark) cycles can entrain the circadian rhythms of most species possessing circadian clocks. However, much less is understood about how other environmental cycles operate as entraining signals (zeitgebers) to synchronize (entrain) the internal clock with the outside world. Potential non-photic zeitgebers include daily cycles of temperature, food availability, and social signals. This project’s goal is to evaluate the efficacy of temperature cycles of varying amplitudes, ranging from 1°C to 10°C, as potential zeitgebers for two different circadian rhythms, eclosion and locomotor activity, in the flesh fly (Sarcophaga crassipalpis). Both rhythms were monitored in individual flies, using infrared motion detectors, under precisely controlled 24-hour temperature cycles (12 hours of high temperature [thermophase] alternating with 12 hours of low temperature [cryophase]) in constant darkness. Our results show clear entrainment of eclosion, a once-in-a-lifetime event, and locomotor activity, reflecting daily sleep-wake rhythms, in response to temperature cycles at amplitudes of 2.5, 5, and 10o C. At 1o C amplitudes, the evidence indicates a partial effect of temperature on the phasing of the two behaviors but not true entrainment (phase regulation), suggesting that 1o C amplitudes may be near the threshold for detection by the entrainment pathways communicating with the circadian clock. Interestingly, although both light and temperature cycles entrain the locomotor activity rhythm, the entrainment profiles are remarkably different, thereby suggesting that light and temperature cycles activate different behavioral programs. Finally, flies placed under different constant temperatures have endogenous circadian periods of locomotor activity that are remarkably similar, indicating a high level of temperature compensation. Our results provide conclusive evidence that temperature is a strong circadian zeitgeber in flesh flies, thereby expanding the known repertoire of environmental cues these organisms use to sync their internal clock with the world around them. These findings also set the stage for future experiments designed to explore the interactions between light and temperature entrainment mechanisms – these zeitgeber interactions almost certainly occur in nature but have received little or no attention.

Tesis por compendio de publicaciones / La luz y los patrones de alimentación influyeron sobre el comportamiento, fisiología y reloj molecular de dos peces teleósteos. Se clonaron dos criptocromos de lubina (cry1 y cry2), expresándose en todos los tejidos estudiados y mostrando ritmos diarios de expresión en cerebro, hígado y corazón (excepto cry2). La fase (día/noche) de alimentación a demanda en lubina afecta a los patrones diarios de actividad amilasa intestinal y expresión de period1 en tejidos periféricos (i.e. hígado), pero no en cerebro. Durante las inversiones estacionales de alimentación de la lubina, mostraron mayores valores de glucosa sanguínea durante la fase de alimentación, revelando también los mayores valores medios en lubinas nocturnas invierno. El pez cebra utilizó un nuevo comedero a demanda, mostrando independencia de fase entre ritmos circadianos de alimentación (nocturno) y locomoción (diurno), con diferentes periodicidades. Además la actividad y posición del pez cebra resultó espectro-dependiente, provocando mayores efectos las longitudes de onda cortas. / Thesis summary in English Light and feeding patterns influence on the behaviour, physiology and molecular clock of two teleost fish. Two cryptochromes (cry1 and cry2) were cloned, being expressed in all studied tissues and showing daily rhythm of expression in brain, liver and heart (except cry2). The self-seabass feeding phase (day/night) affected on daily patterns of intestinal amylase activity and on the period1 expression in peripheral tissues (i.e. liver), but not in brain. During the seasonal feeding inversions in seabass, the highest blood glucose levels were shown during their feeding phase, revealing also the highest values in nocturnal seabass in winter. Zebrafish used a new self-feeding system, displaying phase-independence between feeding (nocturnal) and locomotor (diurnal) circadian rhythms, with different periodicities. Moreover, the zebrafish activity and vertical position were spectrum-dependent, being the main effects provoked by short-wavelengths.

Circadian rhythms dictate the timing of both once-in-a-lifetime adult emergence (eclosion) and daily locomotor activity rhythms in the flesh fly S. crassipalpis. Light cycles are considered the primary environmental time cue (zeitgeber), but the life history of S. crassipalpis suggests that temperature cycles (thermocycles) may also play a key role. This work evaluates the efficacy of thermocycling as a zeitgeber in S. crassipalpis. We found that shifting both light and temperature cycles of sufficient amplitude affect the phasing of eclosion and locomotor activity, but result in different patterns. Additional experiments suggest greater thermocycle sensitivity during the late metamorphic period and that thermocycling reduces variance in eclosion times. Taken together, these findings suggest that temperature cycles can be used by S. crassipalpis to time eclosion and adult locomotor activity, and that S. crassipalpis may be physiologically primed to use thermocycle information during metamorphosis.