What keeps us awake: the neuropharmacology of stimulants and wakefulness-promoting medications

Sleep. 2004 Sep 15;27(6):1181-94. doi: 10.1093/sleep/27.6.1181.


Numerous studies dissecting the basic mechanisms that control sleep regulation have led to considerable improvement in our knowledge of sleep disorders. It is now well accepted that transitions between sleep and wakefulness are regulated by complex neurobiologic mechanisms, which, ultimately, can be delineated as oscillations between two opponent processes, one promoting sleep and the other promoting wakefulness. The role of several neurotransmitter or neuromodulator systems, including noradrenergic, serotonergic, cholinergic, adenosinergic, and histaminergic systems and, more recently, the hypocretin/orexin and dopamine systems, has been clearly established. Amphetamine-like stimulants are known to increase wakefulness by blocking dopamine reuptake, by stimulating dopamine release, or by both mechanisms. Modafinil may increase wakefulness through activation of noradrenergic and dopaminergic systems, possibly through interaction with the hypocretin/orexin system. Caffeine inhibits adenosinergic receptors, which in turn can produce activation via interaction with GABAergic and dopaminergic neurotransmission. Nicotine enhances acetylcholine neurotransmission in the basal forebrain and dopamine release. Understanding the exact role of the hypocretin/orexin and dopamine systems in the physiology and pharmacology of sleep-wake regulation may reveal new insights into current and future wakefulness-promoting drugs.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Amphetamine / pharmacology
  • Amphetamine / therapeutic use
  • Benzhydryl Compounds / pharmacology
  • Benzhydryl Compounds / therapeutic use
  • Brain / drug effects*
  • Central Nervous System Stimulants / pharmacology*
  • Central Nervous System Stimulants / therapeutic use
  • Cocaine / pharmacology
  • Cocaine / therapeutic use
  • Dopamine Uptake Inhibitors / pharmacology*
  • Dopamine Uptake Inhibitors / therapeutic use
  • Humans
  • Methylphenidate / pharmacology
  • Methylphenidate / therapeutic use
  • Modafinil
  • Narcolepsy / drug therapy
  • Nicotine / pharmacology
  • Nicotine / therapeutic use
  • Sleep / drug effects
  • Wakefulness / drug effects*


  • Benzhydryl Compounds
  • Central Nervous System Stimulants
  • Dopamine Uptake Inhibitors
  • Methylphenidate
  • Nicotine
  • Amphetamine
  • Cocaine
  • Modafinil