title: Brain phosphorus magnetic resonance spectroscopy imaging of sleep homeostasis and restoration in drug dependence.
abstract: Numerous reports have documented a high occurrence of sleep difficulties in drug-dependent populations, prompting researchers to characterize sleep profiles and physiology in drug abusing populations. This mini-review examines studies indicating that drug-dependent populations exhibit alterations in sleep homeostatic and restoration processes in response to sleep deprivation. Sleep deprivation is a principal sleep research tool that results in marked physiological challenge, which provides a means to examine sleep homeostatic processes in response to extended wakefulness. A report from our laboratory demonstrated that following recovery sleep from sleep deprivation, brain high-energy phosphates particularly beta-nucleoside triphosphate (beta-NTP) are markedly increased as measured with phosphorus magnetic resonance spectroscopy (MRS). A more recent study examined the effects of sleep deprivation in opiate-dependent methadone-maintained (MM) subjects. The study demonstrated increases in brain beta-NTP following recovery sleep. Interestingly, these increases were of a markedly greater magnitude in MM subjects compared to control subjects. A similar study examined sleep deprivation in cocaine-dependent subjects demonstrating that cocaine-dependent subjects exhibit greater increases in brain beta-NTP following recovery sleep when compared to control subjects. The studies suggest that sleep deprivation in both MM subjects and cocaine-dependent subjects is characterized by greater changes in brain ATP levels than control subjects. Greater enhancements in brain ATP following recovery sleep may reflect a greater disruption to or impact of sleep deprivation in drug dependent subjects, whereby sleep restoration processes may be unable to properly regulate brain ATP and maintain brain high-energy equilibrium. These studies support the notion of a greater susceptibility to sleep loss in drug dependent populations. Additional sleep studies in drug abusing populations are needed, particularly those that examine potential differential effects of sleep deprivation.
authors.affiliation: Behavioral Pharmacology Research Laboratory, McLean Hospital, Belmont, MA, USA. Gtrksak@mclean.harvard.edu
authors.forename: George H
authors.initials: GH
authors.lastname: Trksak
authors.forename: J Eric
authors.initials: JE
authors.lastname: Jensen
authors.forename: Perry F
authors.initials: PF
authors.lastname: Renshaw
authors.forename: Scott E
authors.initials: SE
authors.lastname: Lukas
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology*; D006706:Homeostasis / Q000187:drug effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D010758:Phosphorus / Q000378:metabolism*; D012890:Sleep / Q000502:physiology*; D019966:Substance-Related Disorders / Q000378:metabolism* / Q000503:physiopathology*
chemical_list: D010758:Phosphorus