Influence of sleep deprivation and morphine on the expression of inducible nitric oxide synthase and cyclooxygenase-2 in skin of hairless mice

Known unknowns: A review of opioid-induced hyperalgesia

Opioid-induced hyperalgesia (OIH) is a relatively new paradigm that has added to the already growing uncertainty surrounding long-term opioid treatment. OIH is the oversensitization to stimuli in the nervous system resulting from opioid exposure and subsequent neuroplastic changes. Because of its novelty and difficulty in identification, the true prevalence of OIH is unknown. Several mechanisms have been proposed for its development. These include changes in the N-methyl-D-aspartate system, descending pathway modulation, dynorphin activity, inflammatory changes mediated by cyclooxygenase, and increased sensitivity to excitatory neurochemicals. The clinical controversy regarding the management of OIH is due largely to the lack of guidance in diagnosis and lack of quality evidence to direct treatment. As a diagnosis of exclusion, several alternative causes of antianalgesia must be ruled out before OIH can be declared. Pharmacodynamic phenomena such as opioid tolerance share overlapping mechanisms with OIH and may present similarly. Pharmacokinetic changes such as drug-induced or disease-induced alterations to the cytochrome P450 or P-glycoprotein systems should also be excluded as causes of increased opioid demand that may be seen as OIH. Certain pharmacologic agents, such as N-methyl-D-aspartate receptor antagonists, alpha2 receptor agonists, and cyclooxygenase inhibitors, have been identified as possible treatments to reverse the effects of OIH. Opioid rotation and dose reductions have also been used with some degree of success. Pharmacist involvement in the identification and management of OIH will be central to success because of the unique expertise they offer. The quality of these studies is limited by study design, small sample sizes, and lack of generalizability to chronic pain patients with long-standing opioid use.

Sleep deprivation and oxidative stress in animal models: a systematic review

Because the function and mechanisms of sleep are partially clear, here we applied a meta-analysis to address the issue whether sleep function includes antioxidative properties in mice and rats. Given the expansion of the knowledge in the sleep field, it is indeed ambitious to describe all mammals, or other animals, in which sleep shows an antioxidant function. However, in this paper we reviewed the current understanding from basic studies in two species to drive the hypothesis that sleep is a dynamic-resting state with antioxidative properties. We performed a systematic review of articles cited in Medline, Scopus, and Web of Science until March 2015 using the following search terms: Sleep or sleep deprivation and oxidative stress, lipid peroxidation, glutathione, nitric oxide, catalase or superoxide dismutase. We found a total of 266 studies. After inclusion and exclusion criteria, 44 articles were included, which are presented and discussed in this study. The complex relationship between sleep duration and oxidative stress is discussed. Further studies should consider molecular and genetic approaches to determine whether disrupted sleep promotes oxidative stress.

Endogenous opiates and behavior: 2013

This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.