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9 Cards in this Set
- Front
- Back
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What are the biological effects of melatonin? |
1. Promotes sleep 2. Affects reproductive formations by depressing gonadal activity - which affects thyroid and adrenal cortex 3. Season effective disorder - over production of melatonin 4. Role in initiating puberty |
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What is melatonin secretion controlled by? What is the production driven by? |
Controlled by light - produced in the pineal gland at night and also released at night. Ganglion cells in the eye report on the lack of light. Production is driven by a poly synaptic pathway from the suprachiasmatic nucleus. |
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What is melatonin generated from? |
Tryptophan and serotonin which diffuses across the blood brain barrier into the blood stream. |
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What is the rate limiting enzyme of melatonin biosynthesis? |
Arylalkylanine-N-Acetyl transferase (AA-NAT) |
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What is the activity of AA-NAT driven by? |
By noradrenergic stimulation of the pineal gland |
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Why does seasonal affective disorder occur? |
Due to the pathway of melatonin production including serotonin, as the concentration of melatonin rises, the amount of serotonin drops. |
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What types of receptors are melotonin receptors? |
G Protein coupled receptors - inhibitory type (Gi). |
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Where are the major melatonin receptors found? What is the name of the type of melatonin receptor? |
MT1a - In the suprachiasmtic nucleus, pituitary gland, cardiac blood vessels MT1b - In the retina and hippocampus |
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How is melatonin linked to cancer? |
Melatonin receptor stimulation reduces linoleic acid uptake - a major energy source for tumour cell growth. |
