Question

A man is having difficulty sleeping during the night. He has the habit of drinking coffee before bedtime. What is the role of caffeine in wakefulness?

• A. Blocks adenosine action and causes wakefulness
• B. Activates locus coeruleus and causes wakefulness
• C. No role in maintaining wakefulness if taken 1hr before sleep
• D. Activates histamine release and prevents sleep

Hint:

Caffeine blocks adenosine receptors, preventing the sleep-promoting effects of adenosine and thereby promoting wakefulness.

Answer 1

The Correct Option is A

Caffeine is a central nervous system stimulant commonly found in coffee. Its primary mechanism of action that contributes to promoting wakefulness is by blocking the action of a neurotransmitter called adenosine in the brain. Adenosine naturally promotes sleep and relaxation, and its levels increase with each hour an individual is awake. By blocking adenosine receptors, caffeine prevents the onset of drowsiness and maintains alertness, making it difficult for a person to fall asleep. This is why consuming coffee or other caffeine-containing products before bedtime can interfere with sleep.

To sum up: caffeine blocks adenosine action and causes wakefulness, making it challenging to sleep when consumed close to bedtime.