NARCOLEPSY IN THE BRAIN:
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A lot of what happens when we sleep has to do with how our brains perceive light. The green section pictured in this diagram refers to the hypothalamus, the part of the brain that regulates many important chemicals. In the hypothalamus, there is a cluster of nerves called the suprachiasmatic nucleus (or the SCN). These nerves transmit information about the light we perceive with our eyes.
The pineal gland (named for it's pinecone-like shape) is located nearby the suprachiasmatic nucleus. It produces melatonin. Melatonin is thought to be the hormone in the body that regulates time, or set's our "body-clock." Melatonin appears to trigger sleep or sleepiness.
When your eyes take in more light, your SCN sends a certain signal to the pineal gland to produce less melatonin. In the nighttime, when your brain perceives less light, melatonin is secreted for a longer period of time, regulating your sleep cycle.
The pineal gland (named for it's pinecone-like shape) is located nearby the suprachiasmatic nucleus. It produces melatonin. Melatonin is thought to be the hormone in the body that regulates time, or set's our "body-clock." Melatonin appears to trigger sleep or sleepiness.
When your eyes take in more light, your SCN sends a certain signal to the pineal gland to produce less melatonin. In the nighttime, when your brain perceives less light, melatonin is secreted for a longer period of time, regulating your sleep cycle.
what is hypocretin?
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Hypocretin is a small protein that regulates activity in the hypothalamus. It regulates wakefulness and inhibits REM sleep. Cataplexy is associated with hypocretin deficiency. Hypocretin deficiencies can cause many problems associated with sleep attacks. According to the NY Times In-Depth Report on Narcolepsy, these are some of the chemical responses associated with hypocretin deficiencies that may produce sleep attacks:
- lower levels of histamine, a chemical that promotes wakefulness
- low levels of epinephrine (commonly known as adrenaline), a hormone important in alertness and arousal
- increase in acetylcholine, which affects REM sleep
- changes in the enzyme monoamine oxidase, which is believed to be important in preventing arousal
- changes in dopamine, an important neurotransmitter (chemical messenger in the brain) that helps regulate sleep
- lower levels of leptin, a hormone associated with obesity when levels decline (people with narcolepsy tend to be overweight)
- higher-than-normal secretion of growth-hormone during the day, which may play a role is sudden falling-asleep episodes