Dopamine sleep

Complicated processes govern wakefulness, sleep, and the transitions leading to sleep initiation and maintenance. Although the neurophysiology of sleep is complex, certain neurotransmitters promote sleep and wakefulness in different areas of the central nervous system (CNS). Serotonin is thought to control non-REM sleep, whereas cholinergic and adrenergic transmitters mediate REM sleep. Dopamine, norepinephrine, hypocretin, substance P, and histamine all play a role in wakefulness. Perturbations of various neurotransmitters are responsible for some sleep disorders and explain why various treatment modalities are beneficial. 

Caffeine binds to adenosine receptors in the brain, preventing adenosine from inducing sleep or opening blood vessels. Caffeine also increases levels of dopamine, the neurotransmitter associated with pleasure. This is the chemical mechanism for addiction. The response to adenosine competition causes increased adrenaline flow. 

FIGURE 38-1. Primary assessment and initial treatment for complaint of excessive daytime sleepiness. RLS, restless-legs syndrome NPSG, nocturnal polysomnography OSA, obstructive sleep apnea DA, dopamine agonist MSLT, multiple sleep latency test BZDRA, benzodiazepine receptor agonist SNRI, serotonin and norepinephrine reuptake inhibitor TCA, tricyclic antidepressant CPAP, continuous positive airway pressure. 

In the vertebrate CNS monoamines have been associated with a number of physiological functions (reviewed in Kandel et al., 1991). Serotonin has functions associated with mood, pain, sleep, learning, and memory. Dopamine has functions associated with schizophrenia, Parkinson s disease, and cocaine addiction. In vertebrates, dopamine is further metabolized into two additional neurotransmitters, norepinephrine and epinephrine. Norepinephrine increases the excitability of cells in response to sudden sensory input such as fear. Epinephrine has been identified in specific neurons of the brain, but the function of these cells is unknown. In addition, AADC has also been found in a class of neurons that do not have any of the four neurotransmitters discussed above (Jaeger et al., 1983). These neurons may use one of the trace amines, tyramine, tryptamine, or phenylethylamine, as a neurotransmitter. 

Lena, I., Parrot, S., Deschaux, O. et al. (2005). Variations in extracellular levels of dopamine, noradrenaline, glutamate, and aspartate across the sleep - wake cycle in the medial prefrontal cortex and nucleus accumbens of freely moving rats. J. Neurosci. Res. 81, 891-9. 

Figure 7.2 Diurnal variation of extracellular dopamine in the non-human primate putamen. Dopamine concentrations (dm) as determined by high-pressure liquid chromatography of microdialysates obtained from the putamen of two rhesus monkeys across their 12 12 h lights-on (waking 7 00 am 7 00 pm) and lights off (sleep 7 00 pm-7 00 am) periods. Ten minute samples (2 pl/min sampling rate) were derived from nine individual 8 h sessions in each animal in which the sleep-wake state was monitored simultaneously by standard electrophysiological parameters.

Wake-sleep-related, physiology of mesotelencephalic dopamine neurons... 

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