One of the most consistent behavioral changes that occurs with age in humans is the loss of sleep consolidation. This can be quite disruptive and yet little is known about its underlying basis. To better understand the effects of aging on sleep:wake cycles, we sought to study this problem in Drosophila melanogaster, a powerful system for research on aging and behavior. By assaying flies of different ages as well as monitoring individual flies constantly over the course of their lifetime, we found that the strength of sleep:wake cycles decreased and that sleep became more fragmented with age in Drosophila. These changes in sleep:wake cycles became faster or slower with manipulations of ambient temperature that decreased or increased lifespan, respectively, demonstrating that they are a function of physiological rather than chronological age. The effect of temperature on lifespan was not mediated by changes in overall activity level or sleep amount. Flies treated with the oxidative stress-producing reagent paraquat showed a breakdown of sleep:wake cycles similar to that seen with aging, leading us to propose that the accumulation of oxidative damage with age contributes to the changes in rhythm and sleep. Together, these findings establish Drosophila as a valuable model for studying age-associated sleep fragmentation and breakdown of rhythm strength, and indicate that these changes in sleep:wake cycles are an integral part of the physiological aging process.aging ͉ circadian rhythms ͉ sleep fragmentation

The rostral agranular insular cortex (RAIC) of rats has opioid receptors and has been implicated in the analgesic and reinforcing effects of opiates. To help in understanding the function of endogenous opioids in this structure, we sought to identify and describe the opioid peptides intrinsic to the RAIC by using immunohistochemical methods. Immunolabeling for proopiomelanocortin (POMC), the precursor to beta-endorphin, and endomorphin 1 and 2 on sectioned rat forebrain revealed limited labeling consisting of individual varicose fibers. Immunolabeling for prodynorphin and enkephalin revealed numerous immunopositive cell bodies and fibers with distribution and morphology unique to each. Prodynorphin-immunopositive cell bodies consisted of two types: large, lightly labeled, pyramidal-shaped cell bodies in lamina V and more intensely labeled, small, ovoid cell bodies scattered in other lamina. Axonal fibers immunolabeled for prodynorphin varied in size and were found in all lamina. Immunolabeling for the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) was rarely found in dynorphin-containing cell bodies (6%, 10/167) but was visible within a subpopulation of axons. Enkephalin immunolabeling was detected within a single morphological subpopulation of nonpyramidal neurons located predominantly in lamina II/III, 30% (33/109) of which were also GABA immunopositive. Axons immunolabeled for enkephalin were also abundant in lamina II/III. These results suggest that dynorphin and enkephalin peptides are the predominant endogenous opioids in the RAIC and their distinct distributions suggest divergent functional roles. The localization of prodynorphin immunoreactivity to pyramidal cells suggests the possibility that this neuropeptide may be used in RAIC projection neurons, whereas enkephalin distribution was more characteristic of a role in local networks.

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In what sense did Augustine attribute desires to the human body itself? Scholars disagree substantially about how to answer this question, yet it has rarely been treated as anything approaching a scholarly quaestio disputata. Some hold that bodily desire is in principle impossible according to Augustine’s anthropology. Others hold that bodily desire is of marginal significance in Augustine’s system. Still others hold that bodily desire is a central problem in human life according to Augustine. This essay is an intervention intended to prompt further exchange about the interpretation of Augustine’s thought on the issue of bodily desire. To achieve that goal, the essay closely examines two texts from Augustine’s writings against Julian of Eclanum in the early 420s. In book I of De nuptiis et concupiscentia, Augustine argues that the body does have its own desires and they are an extensive problem in human life. Furthermore, in Contra Iulianum we find that Augustine himself responds to three crucial objections that might be raised against my interpretation. In short, late in his life Augustine treated bodily desire as a grave and pervasive problem. The essay does not address his views in his earlier works. As an intervention, the essay inevitably prompts important questions it cannot fully address, especially around Augustine’s philosophy of mind, the development of Augustine’s thought, and the implications of Augustine’s claims about the body for other elements of his theological project. Future investigations will hopefully take up these topics in the scholarly exchange this intervention intends to foster.