Melatonin

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A Seminar on melatonin hormone

Presented By- Kuldeep Kinja M Pharma 2nd
Yr Pharmacology
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INTRODUCTION

• Melatonin also known chemically as
  N-acetyl-5-methoxytryptamine.
• Is a naturally occurring compound found in
  animals, plants, and microbes.
• In animals,circulating levels of the hormone
  melatonin vary in a daily cycle.
• Allowing the entrainment of the circadian
  rhythms of several biological function .
• It produced in the pineal gland which is outside
  of the blood-brain barrier acts as an endocrine
  hormone since it is released into the blood
• melatonin produced by the retina and the
  gastrointestinal (GI) tract

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• Many biological effects of melatonin are produced
  through activation of melatonin receptors
• powerful antioxidant, with a particular role in
  the protection of nuclear and mitochondrial DNA
• Known as the "hormone of darkness", it is
  secreted in darkness in both day-active (diurnal)
  and night-active (nocturnal) .
• It may also be produced by a variety of
  peripheral cells such as bone marrow cells,
  lymphocytes and epithelial cells.

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HISTORY
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Melatonin receptors

• Found in central nervous system and peripheral
• tissues
• In brain MT1 AND MT2 receptors are found in
  membranes of neurons of (SCN).
• MTI AND MT2 are G-protien-couple receptors.
• MT3 receptor is also found which is poorly
  understood.

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G-protein couple receptor

• They also called the metabotropic receptor.
• Have three subunits
• 1-Alpha
• 2-beta
• 3-gamma
• Seven transmembrane receptors.
• Called Heptahelical receptor

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Working of G-protein Receptor
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G-protein couple receptor effector system

• 1- Adenylate cyclase/C-AMP sytem
• 2- phospholipase C / inositol
  phosphate system

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Mechenisum of MT1 receptor
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Mechenisum of MT2 receptor
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Agonist of melatonin receptor

• Very few have been discovered
• 1-Ramelteon selective for MT1 MT2 is approved
  for treatment of insomnia.
• 2-luzindole
• 3-4P-ADOT

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SYNTHESIS OF MELATONIN

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• MELATONIN IN PLANTS
• In plants involve regulation of their response to
  photoperiod, defense against harsh environments,
  and the function of an antioxidant.
• Melatonin has been reported in foodstuffs
  including bananas and grapes, rice and cereals,
  herbs, olive oil, wine and beer.
• While no food has been found to elevate plasma
  melatonin levels in humans,when other animals
  consume melatonin-containing food, blood levels
  of melatonin do increase

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MELATONIN IN ANIMALS

• Melatonin can suppress libido by inhibiting
  secretion of (LH) and (FSH) especially in
  mammals that have a breeding season when daylight
  hours are long.
• The reproduction of long-day breeders is
  repressed by melatonin and the reproduction of
  short-day breeders is stimulated by melatonin.

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In Human

• The melatonin signal forms part of the system
  that regulates the sleep-wake cycle.
• Infants melatonin levels become regular in about
  the third month after birth, with the highest
  levels measured between midnight and (8 AM).
• In humans, 90 of melatonin is cleared through
  the liver, a small amount is excreted in urine
  and a small amount is found in saliva.

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Light dependence

• Production of melatonin by the pineal gland is
  inhibited by light and permitted by darkness. SO
  called "the hormone of darkness.
• Its onset called the Dim-Light Melatonin Onset
  (DLMO).
• Secretion in blood peaks in the middle of the
  night, and gradually falls during the second half
  of the night.
• When used several hours before sleep, the
  compound shifts the circadian clock earlier, thus
  promoting earlier sleep onset and morning
  awakening.

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• Cont
• It is principally blue light, around 460 to 480nm
  that suppresses melatonin.
• Kayumov showed that light containing only
  wavelengths greater than 530 nm does not suppress
  melatonin in bright-light conditions
• Use of blue-blocking goggles the last hours
  before bedtime advised for people who need to
  adjust to an earlier bedtime, as melatonin
  promotes sleepiness.

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Melatonin as antioxidant

• The discovery of melatonin as an antioxidant was
  made in 1993.
• Melatonin is a direct scavenger of OH, and NO.
• Melatonin once oxidized cannot be reduced to its
  former state because it forms several stable
  end-products upon reacting with free radicals.
• Called terminal or suicidal antioxidant.

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MELATONIN IN IMMUNE SYSTEM

• immunological effect is thought to result from
  melatonin acting on high affinity receptors (MT1
  and MT2).
• melatonin may enhance cytokine production
• melatonin might be useful fighting infectious
  disease including viral, such as HIV and
  bacterial infections, and cancer.
• Endogenous melatonin in human lymphocytes has
  been related to interleukin-2 (IL-2) production.

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MELATONIN IN DREAM

• Increase in vivid dreaming.
• 2 to10 mg increase the propensity of falling seep
  .
• 80mg can induce sleep in adult man.
• Extremely high doses of melatonin (50 mg)
  increased REM sleep time . Many drugs such as
  cannabis increase melatonin synthesis.

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MAKETED PRODUCT
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REFERENCES

• RANG DALES PHARMACOLOGY sixth edition ,
  churchill livingstone Publishers,page-no-503 to
  504.
• Katzung.g,trevor.j basic and cilinical
  pharmacology 11th edition,Tata McGraw-Hill
  publishers,page-no-1023to1025.
• Gillmans Goodmans the pharmacological basics
  of therapeutics Edition 10th, McGraw-hill
  Medical publishing division,page no-270.
• www.wikipedia.com
• http//www.drugs.com/melatonin.html

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• www.wikipedia.com
• http//www.drugs.com/melatonin.html