Our results suggest that glucocorticoids do not mediate memory impairments but might be responsible for the weight loss induced by paradoxical sleep deprivation.

In this work, the thermoluminescent properties of pellets containing powdered Wollastonite embedded in Teflon were studied. The preliminary results using gamma rays from a 60 Co source showed linearity at the calibration curve between 0.5 Gy and 10 Gy. The main TL peaks are located at 125, 200 and 245 °C. The repeatibility of TL response presented a maximum coefficient of variation of 6.3%. The material can be used in successive irradiation-reading-annealing cycles without an appreciable change in its sensitivity. The calibration curve for a gamma source ( 60 Co) up to 20 kGy and the minimum detection limits were obtained. The results show that these Wollastonite-Teflon pellets present possibilities for use as TL dosimeters.

Background: Sleep loss in infants may have a negative effect on the functional and structural development of the nociceptive system. We tested the hypothesis that neonatal sleep restriction induces a long-term increase of pain-related behaviors in mice and that this hypersensitivity occurs due to changes in the neuronal activity of nociceptive pathways. Objectives: We aim to investigate the effects of sleep loss in neonatal mice on pain behaviors of adolescent and adult mice in a sex-dependent manner. We also analyzed neuroanatomical and functional changes in pain pathways associated with behavioral changes. Study Design: An experimental animal study. Setting: A basic sleep research laboratory at Universidade Federal de São Paulo in Brazil. Methods: Neonatal mice at postnatal day (PND) 12 were randomly assigned to either control (CTRL), maternal separation (MS), or sleep restriction (SR) groups. MS and SR were performed 2 hours a day for 10 days (PND 12 until PND 21). The gentle handling method was used to prevent sleep. At PND 21, PND 35, or PND 90, the mice were tested for pain-related behaviors. Their brains were harvested and immunohistochemically stained for c-Fos protein in the anterior cingulate cortex, primary somatosensory cortex, and periaqueductal gray (PAG). Results: Neonatal SR significantly increased nociceptive sensitivity in the hot plate test in adolescent mice (-23.5% of pain threshold). This alteration in nociceptive response was accompanied by a decrease in c-Fos expression in PAG (-40% of c-Fos positive cells compared to the CTRL group). The hypersensitivity found in adolescent mice was not present in adult animals, and all mice showed a comparable nociceptive response. Limitations: Even using a mild manipulation method, in which a minimal amount of handling was applied to maintain wakefulness, sleep deprivation was a stressful event evidenced by higher corticosterone levels. Conclusion: Repeated exposures to sleep loss during early life were able to induce changes in the nociceptive response associated with alterations in neural activity in descending control of pain. Key words: Brain maturation, hypersensitivity, neuronal activity, nociception, pain, periaqueductal gray, postnatal development, sleep, sleep deprivation

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