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Review Papers | Neuroscience | India | Volume 12 Issue 7, July 2023 | Rating: 5.2 / 10
Our Current Understanding of Theneurochemical Basis of Homeostatic Mechanisms that Regulate Sleep is Incomplete
Mousumi Chakrabarty [2] | Priya Gajendra Shinde
Abstract: The modern - day concept of 'sleep - wake regulation' was first proposed by Alexander Borbely in 1982. This two - process model proposes that there are primarily two mechanisms that control this cycle - 'process C' or circadian rhythm and 'process S' or homeostatic control. Numerous experiments in the past have enriched us with the knowledge of the neurochemical basis of the homeostatic regulation of sleep. The arousal systems are located mainly in the brainstem, posterior and lateral hypothalamus and basal forebrain. These networks utilize a number of neurotransmitters such as histamine, acetylcholine, serotonin, norepinephrine, dopamine, glutamate and orexin/hypocretin to promote wakefulness. The normal circadian cycle starts with the activation of SCN by sunlight. SCN then stimulates the LH and the TMN nucleus and through the neurotransmitters noradrenaline, serotonin and acetylcholine maintain wakefulness. During the day, the tonic activity of the SCN increases progressively and counteracts the homeostatic sleep drive till evening. By late evening, the pineal gland starts secreting melatonin. A second internal mechanism that promotes sleep results from the accumulation of inhibitory neurotransmitter adenosine which activates VLPO which in turn inhibits the wake - promoting nuclei and ensures sleep. Thus, the homeostatic regulation of sleep involves a very complex network of activities of different sleep substances, neurotransmitters and hormones on the various sleep and wake areas of the brain some of which have been discovered and described but there may be many more waiting to be discovered. Our present knowledge therefore is incomplete and lacks a complete grasp of the neurochemical basis of sleep.
Keywords: Homeostatic Mechanism, Sleep
Edition: Volume 12 Issue 7, July 2023,
Pages: 1530 - 1534