title: Dopaminergic role in regulating neurophysiological markers of sleep homeostasis in humans.
abstract: While dopamine affects fundamental brain processes such as movement control, emotional responses, addiction, and pain, the roles for this neurotransmitter in regulating wakefulness and sleep are incompletely understood. Genetically modified animal models with reduced dopamine clearance exhibit hypersensitivity to caffeine, reduced-responsiveness to modafinil, and increased homeostatic response to prolonged wakefulness when compared with wild-type animals. Here we studied sleep-wake regulation in humans and combined pharmacogenetic and neurophysiologic methods to analyze the effects of the 3'-UTR variable-number-tandem-repeat polymorphism of the gene (DAT1, SLC6A3) encoding dopamine transporter (DAT). Previous research demonstrated that healthy homozygous 10-repeat (10R/10R) allele carriers of this genetic variant have reduced striatal DAT protein expression when compared with 9-repeat (9R) allele carriers. Objective and subjective estimates of caffeine sensitivity were higher in 10R allele homozygotes than in carriers of the 9R allele. Moreover, caffeine and modafinil affected wakefulness-induced changes in functional bands (delta, sigma, beta) of rhythmic brain activity in wakefulness and sleep in a DAT1 genotype-dependent manner. Finally, the sleep deprivation-induced increase in well established neurophysiologic markers of sleep homeostasis, including slow-wave sleep, electroencephalographic slow-wave activity (0.5-4.5 Hz), and number of low-frequency (0.5-2.0 Hz) oscillations in non-rapid-eye-movement sleep, was significantly larger in the 10R/10R genotype than in the 9R allele carriers of DAT1. Together, the data suggest that the dopamine transporter contributes to homeostatic sleep-wake regulation in humans.
authors.affiliation: Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland, Institute of Medical Molecular Genetics, University of Zürich, CH-8952 Schlieren, Switzerland, Zürich Center for Integrative Human Physiology, University of Zürich, 8057 Zürich, Switzerland, and Neuroscience Center Zurich, University of Zürich and ETH Zürich, 8057 Zürich, Switzerland.
authors.forename: Sebastian C
authors.initials: SC
authors.lastname: Holst
authors.forename: Alessia
authors.initials: A
authors.lastname: Bersagliere
authors.forename: Valérie
authors.initials: V
authors.lastname: Bachmann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Berger
authors.forename: Peter
authors.initials: P
authors.lastname: Achermann
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Landolt
mesh_terms: D000293:Adolescent; D000328:Adult; D004298:Dopamine / Q000235:genetics* / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics*; D004569:Electroencephalography; D005260:Female; D005838:Genotype; D006706:Homeostasis / Q000235:genetics*; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D017286:Polysomnography; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012890:Sleep / Q000235:genetics*; D055815:Young Adult
chemical_list: D050483:Dopamine Plasma Membrane Transport Proteins; D004298:Dopamine