To examine the role of light in the maturation of the circadian pacemaker, twelve groups of rats were raised in different conditions of exposure to constant bright light (LL) during lactation: both duration and timing of LL were varied. We studied the motor activity rhythm of the rats after weaning, first under LL and then under constant darkness (DD). In DD, two light pulses [at circadian time 15 (CT15) and CT22] were applied to test the response of the pacemaker. Greater exposure to LL days during lactation increased the number of rhythmic animals and the amplitude of their motor activity rhythm in the LL stage and decreased the phase delay due to the light pulse at CT15. The timing of LL during lactation affected these variables too. Because the response of the adult to light depended on both the number and timing of LL days during lactation, the exposure to light at early stages may influence the development of the circadian system by modifying it structurally or functionally.

The motor activity circadian rhythm of the rat is driven by at least two different pacemakers, one entrained by light-dark cycles and the other by periodic food access. The interaction between these two pacemakers generates the overt rhythm in many variables in the rat. In this paper we study the effects of restricted feeding (RF) for > 300 days on the motor activity of two groups of eight rats each (4 males and 4 females) that were kept under different light patterns. The first group was kept under dim red light, and the second group was kept initially for 70 days under bright light and afterward under dim red light. Rats had access to food for only 2 h/day. Results show that strong alterations in the motor activity pattern, such as relative coordination, bouncing, and several cases of entrainment, are shown in the first group. When these animals return to ad libitum feeding conditions the presence of the food component is clear, in some cases for > 20 days. In contrast, the rats that were previously subjected to bright light did not entrain to RF. In this group, there was a masking effect when lights were on, but a free-running component appeared when lights were off. The endogenous period (tau) of this component was not modified during the course of the experiment. After RF these rats showed a longer tau than the former group.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol consumption is highly prevalent in university students. Early detection in future health professionals is important: their consumption might not only influence their own health but may determine how they deal with the implementation of preventive strategies in the future. The aim of this paper is to detect the prevalence of risky alcohol consumption in first-and last-degree year students and to compare their drinking patterns. Risky drinking in pharmacy students (n=434) was assessed and measured with the AUDIT questionnaire (Alcohol Use Disorders Identification Test). A comparative analysis between college students from the first and fifth years of the degree in pharmacy, and that of a group of professors was carried to see differences in their alcohol intake patterns. Risky drinking was detected in 31.3% of students. The highest prevalence of risky drinkers, and the total score of the AUDIT test was found in students in their first academic year. Students in the first academic level taking morning classes had a twofold risk of risky drinking (OR=1.9 (IC 95%1.1-3.1)) compared with students in the fifth level. The frequency of alcohol consumption increases with the academic level, whereas the number of alcohol beverages per drinking occasion falls. Risky drinking is high during the first year of university. As alcohol consumption might decrease with age, it is important to design preventive strategies that will strengthen this tendency.

Purpose There is accumulating evidence of autonomic dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS); however, little is known about its association with circadian rhythms and endothelial dysfunction. This study aimed to explore the relationship between autonomic responses using an orthostatic test, skin temperature circadian variations, and circulating endothelial biomarkers in ME/CFS. Methods Sixty-seven adult female ME/CFS patients and 48 matched healthy controls were enrolled. Demographic and clinical characteristics suggestive of autonomic disturbances were assessed using validated self-reported outcome measures. Postural changes in blood pressure [BP], heart rate [HR], and wrist temperature (WT) were recorded during the orthostatic test. Actigraphy during one week was used to determine the 24-hour profile of peripheral temperature and motor activity. Circulating endothelial biomarkers were also measured as indicators of endothelial functioning. Results ME/CFS patients showed higher BP and HR values than healthy controls at rest (p < 0.05 for both), and also higher amplitude of the circadian activity rhythm (p < 0.01). Circulating levels of endothelin-1 (ET-1) and vascular cell adhesion molecule-1 (VCAM-1) were significantly higher in ME/CFS (p < 0.05). In ME/CFS, ET-1 levels were associated with the stability and amplitude of the temperature rhythm, (p < 0.01), and also with the self-reported questionnaires (p < 0.001). Conclusions ME/CFS patients exhibited alterations in circadian rhythms and hemodynamic measures that are associated with endothelial dysfunction, supporting previous evidence of dysautonomia in ME/CFS. Future investigation in this area is needed to assess vascular tone abnormalities and dysautonomia which may provide therapeutic targets for ME/CFS.

No abstract