Sleep Disorders Flashcards
Where is melatonin released from?
Pineal gland
What is the role of the suprachiasmatic nucleus?
To stimulate the pineal gland to release melatonin
What increases concentrations of melatonin?
Darkness
When are cortisol levels highest?
In the morning
What constitutes a sleep disorder?
Conditions that affect the ability to sleep well on a regular basis and interferes with daily life
What is insomnia?
Difficulty falling or staying asleep
What is sleep apnoea?
Breathing repeatedly starts and stops during sleep
What is hypersomnia?
Exhaustion even after a full nights sleep
What is narcolepsy?
Irregular sleep wake cycles
What is parasomnia?
Unusual behaviour during sleep
What are results of insomnia?
Irritability Mood changes Poor concentration Memory defects Increased appetite Impaired creative thinking, verbal processing and problem solving
Describe the rodent model of insomnia
A rodent is placed on an inverted flowerpot with a smaller diameter than their body length. The flowerpot is placed in cold water
At the onset of REM sleep, muscle relaxation occurs so the mouse falls into the cold water and wakes up
What is fatal familial insomnia?
A genetic condition which results in an inability to reach REM sleep which causes dementia
What is the mortality rate for fatal familial insomnia?
100%
What neurological changes are seen in fatal familial insomnia?
Changes in the spongiform cortex
Thalamic atrophy
What is the genetic link to fatal familial insomnia?
Heterozygous D178N mutation, with methionine at position 129 of PRNP gene
How may sleep disorders be diagnosed?
Polysomnography
Wrist actigraphy
Describe polysomnography
The patient sleeps with a number of devices attached that measures eye movement, brain activity, nasal air flow, breathing and blood oxygen saturation
Describe wrist actigraphy
A device is worn on the non-dominant hand to determine time spent sleeping in each stage of sleep
What is the link between schizophrenia and sleep?
Schizophrenic patients saw a shift in sleep onset, melatonin peak and sleep offset which may contribute to hallucinations and psychosis
Which hormones promote sleep?
GABA, melatonin, adenosine
Which hormones promote wakefulness?
Noradrenaline, dopamine, serotonin, histamine, acetylcholine, hypocretin
What may be used to treat insomnia?
Benzodiazepines Benzodiazepine receptor agonists Antidepressants Hypocretin antagonists Melatonin agonists Anticonvulsants
What is the mechanism of a benzodiazepine or benzodiazepine receptor agonist?
Binding to Alpha-1 GABA subunit to increase sleep duration
Give an example of a benzodiazepine?
Clonazepam, clorazepate, diazepam, lorazepam, temazepam
Give an example of a benzodiazepine receptor agonist
Zolpidem, zaleplon, zopiclone, eszopiclone
What does drug treatment for narcolepsy aim to do?
Control daytime sleepiness and cataplexy
How does modafinil treat narcoleptic symptoms?
Mechanism unknown
Thought to be a dopamine reuptake inhibitor which increases hypocretins and histamines
How does methylphenidate treat narcoleptic symptoms?
Noradrenaline-dopamine reuptake inhibitor
How does sodium oxybate treat narcoleptic symptoms?
Mostly unknown
Interacts with GABA B receptors
