Neurochemistry of Wakefulness

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Questions and Answers

What effect does REM deprivation have on sleep patterns?

It results in decreased total sleep time

It leads to increased REM sleep later (correct)

It causes longer sleep cycles

It has no effect on sleep

Higher body temperature is associated with less REM sleep.

False

Name a class of drugs that suppress REM sleep.

Barbiturates

Most OTC sleep aids are __________.

anti-histamines Signup and view all the answers

Which of the following is a characteristic of the 'Z drugs' used for treating insomnia?

They produce an amnesic state Signup and view all the answers

Ramelton is a melatonin antagonist.

False Signup and view all the answers

What are the two types of oxerin receptors?

OX1R and OX2R Signup and view all the answers

Match the following sleep aids with their characteristics:

Zolpidem (Ambien) = Z drug with a longer half-life Zaleplon (Sonata) = Z drug with a half-life of about an hour Eszopiclone (Lunesta) = Z drug with a half-life of about six hours Suvorexant (Belsomra) = Oxerin receptor antagonist Signup and view all the answers

Which chemical is NOT considered an inhibitory neurotransmitter?

Glutamate Signup and view all the answers

The suprachiasmatic nucleus is responsible for regulating wakefulness.

False Signup and view all the answers

What is the primary role of orexin in the body?

Regulating wakefulness and appetite. Signup and view all the answers

Caffeine acts as an __________ receptor antagonist.

adenosine Signup and view all the answers

Match the following neurotransmitters with their roles:

GABA = Inhibitory Norepinephrine = Excitatory Melatonin = Sleep regulation Acetylcholine = Attention and arousal Signup and view all the answers

What condition is characterized by cell loss in the anterior hypothalamus?

Fatal Familial Insomnia Signup and view all the answers

Stages 3 and 4 of sleep are known as 'Rapid Eye Movement' sleep.

False Signup and view all the answers

How does caffeine affect the activity of dopamine and norepinephrine?

Caffeine suppresses their activity by blocking adenosine receptors. Signup and view all the answers

The brain's 'clock' is referred to as the __________.

suprachiasmatic nucleus Signup and view all the answers

What is the average caffeine content in a cup of coffee?

100 mg Signup and view all the answers

Study Notes

Wakefulness

Wakefulness is regulated by the balance of excitatory and inhibitory neurochemicals.
Excitatory neurochemicals include glutamate, acetylcholine, dopamine, norepinephrine, orexin, and histamine.
Inhibitory neurochemicals include GABA, melatonin, and adenosine.

Neural Control of Wakefulness

Reticular Formation: Releases glutamate in the forebrain.
Basal Forebrain: Releases acetylcholine in the forebrain.
Locus Coeruleus: Releases norepinephrine in the forebrain.
Hypothalamus: Crucial for wakefulness. Damage to the posterior hypothalamus can disrupt wakefulness. Releases histamine and orexin to the forebrain. The loss of orexin-producing neurons causes narcolepsy.
Suprachiasmatic Nucleus (SCN): The brain's internal clock, controlling melatonin release by the pineal gland.

Caffeine

Caffeine is an adenosine receptor antagonist.
Adenosine suppresses excitatory neurochemicals (dopamine, norepinephrine, glutamate, acetylcholine) and enhances GABA activity.
Adenosine accumulates during the day.
A cup of coffee contains ~100 mg of caffeine, a can of soda ~40 mg.
Caffeine is metabolized by CYP-IA2.
Half-life is ~4 hours, with active metabolites extending effects.
Caffeine constricts cerebral vessels, aiding in headaches.
Coffee consumption may protect against type 2 diabetes, cancer, Parkinson's, Alzheimer's, cardiovascular disease, and improve memory, but it can exacerbate anxiety.

Sleep Stages

Brain activity varies during wakefulness.
Brain activity becomes increasingly rhythmic from Stages 1 to 4 (slow-wave sleep).
Sleep isn't the absence of brain activity.
Stages 3-4 slow wave sleep are characterized by rhythmic brain activity, presumably as the hypothalamus stops sending signals to the cortex.
REM sleep is linked to body temperature.
REM deprivation leads to REM rebound.
Some drugs (e.g., barbiturates, alcohol) suppress REM sleep.
Higher body temperature correlates with more REM sleep.

Insomnia

Insomnia is highly comorbid with anxiety.
Types of insomnia include onset, maintenance, and termination.
Body temperature falling promotes sleep onset, while rising temperature promotes wakefulness.

Sleep Aids

Many over-the-counter sleep aids are antihistamines, with the 'Z-drugs' (e.g., Zolpidem, Zaleplon, Eszopiclone) considered for insomnia.
These are Non-benzodiazepine receptor agonists (NBZRAs) with varying half-lives (1-6 hours).
These bind to 1-2 GABA receptor subunits, not all 5.
Some sleep aids can cause amnesic states.
Ramelteon (Rozerem) is a melatonin agonist with a questionable efficacy.
Oxerin receptor antagonists (e.g., Suvorexant - Belsomra) target orexin pathways, preventing arousal system activation. Orexin is a peptide neurotransmitter regulating sleep-wake transitions.

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Description

This quiz explores the complex neurochemical landscape that regulates wakefulness, focusing on the roles of excitatory and inhibitory substances. It delves into the neural control mechanisms including key brain structures such as the reticular formation and hypothalamus, as well as the impact of caffeine on these processes.