Chemical Neurobiology of Sleep Induction and Wakefulness

Sleep and wakefulness are the two fundamental states that govern human life, playing critical roles in the maintenance of physiological homeostasis, cognitive function and emotional wellbeing. The neuropharmacology of sleep wakefulness involves a complex interplay of neurotransmitters, hormones and brain regions that regulate the sleep-wake cycle sleep and wakefulness are dynamic brain states regulated by interacting neural circuits and neuromodulatory systems. Understanding their neuropharmacology is essential for treating insomnia, hypersomnolence, narcolepsy, and other sleep disorders. This article reviews the neuroanatomy and cellular mechanisms of sleep/wake regulation, the major neurotransmitters and neuromodulators (adenosine, GABA, orexin/hypocretin, histamine, monoamines, acetylcholine, dopamine, glutamate, melatonin, endocannabinoids), and how available drugs act on these systems. We summarize evidence for clinically important hypnotics (benzodiazepines, Z-drugs, dual orexin receptor antagonists), wake-promoting agents (modafinil, solriamfetol, pitolisant), and circadian modulators, review clinical guidelines, and discuss emerging pharmacologic targets and safety considerations. This ARTICLE aims to provide an overview of key players and mechanisms involved in the neuropharmacology and the role of acetyl choline which plays a vital role in the regulation of sleep and wake cycle. This article emphasises the role of acetyl choline in sleep-wake cycle.