Melatonin, Questionnaire Example

What broad roles does melatonin play within the healthy human body

Melatonin is a chemical that is involved in a number of human body functions (Ehrlich, 2009). It is perhaps most widely known for regulating the sleep cycle. Nevertheless, there are other things that melatonin is responsible for. For example, it is a key component in the female reproductive cycle. It is also a known antioxidant. Such biorhythmic functions are important for overall health and well-being. They govern everything from breathing to cognition.
Provide information about the classification and/or structure of melatonin. Is it fat – or water soluble?

It is both fat and water soluble (DiGiovanna, 2000). It cannot be concluded simply as a fat or water soluble. Melatonin (5-methoxy-N-acetyltryptamine) is a vital hormonal outcome of the circadian system. It communicates timing cues to tissue. Melatonin receptors are the components that accept and convert this message to affect daily and seasonal rhythms of behavior and physiology.

Neurotransmitter?

Yes.  Melatonin is a neurotransmitter; it acts as a vital component of many signaling molecules (Buehler, 2003).

Hormone?

Yes. It is known as hormone secreted by pineal gland in the brain (Ehrlich, 2009).

Where is melatonin produced?

Melatonin is secreted by Pineal gland in the brain as well as certain parts of the digestive tract. It helps in regulating other hormones and helps in maintaining body’s circadian rhythm (Ehrlich, 2009).

What stimuli tell the body to synthesize or produce melatonin?

The endocrine system guides the body to produce hormones directly into the spaces surrounding their cells (Barron, 2010). The bloodstream picks it up and regulates in the body and finally reaches to a targeted place or hormone. Light is detected by the retina (even when the eye lids are closed) and signals the Pineal gland to reduce production of melatonin.

How does melatonin travel throughout the body (or throughout an area of the body)?

Melatonin gets secreted from a cell and binds to appropriate receptors on the cell membrane that signals cells to alter metabolic process rates (Barron, 2010). It is transported to the periphery thorough the bloodstream where it is influences bio-functions at the cellular level.

What signals tell the body to stop making melatonin?
Darkness tells the body to increase melatonin production (Barron, 2010). Light helps decrease the secretion and regulation of melatonin within the body and darkness helps in increasing it (Barron, 2010).

Is melatonin eliminated or recycled after use? Explain this process?

Melatonin is eliminated through urine (DiGiovanna, 2000). Through urine a required amount can be eliminated after used. As physical activity increases, excess melatonin is filtered through the kidneys out of the blood stream.

Can melatonin levels be measured in healthy humans? How?

Yes (Hsing, Meyer, Niwa, Quraishi, & Chu, 2010).  It can be measured with the help of Serum Melatonin assays of the blood or urine.
Melatonin and the Central Nervous System, (CNS)
Provide an overview of melatonin’s role in the CNS? 

Melatonin is mainly responsible for regulating circadian rhythms (Dubocovich, 2011). It works around retina and brain visual systems as models using functional responses. When light hits the retina, it signals the Pineal gland to reduce production of melatonin. When darkness sheds on the retina, the opposite is true.

What other signaling molecules from within the CNS come into contact with or affect melatonin?

Tryptophan is an amino acid considered as one of the building block of protein (Zwayer, n.d.). The conversion of tryptophan to serotonin can be elevated by number of methods. Patients found low levels of are usually seen depressed. Tryptophan and serotonin are two signaling molecules come into come into contract to affect melatonin.

What changes happen at the tissue/organ level?

Changes occur at different levels and stages, and it varies from human to human, but basically, in darkness, the retina signals the pineal gland to converts tryptophan to melatonin and secrets it into the bloodstream. Once there it tells the brain, digestive system, and other systems of the body to slow metabolic rates of member cells (Zwayer, n.d.).

How does the CNS request melatonin when it is needed?

It signals the pineal gland to release it into the blood stream (Zwayer, n.d.).

Locate two clinical studies relevant to melatonin. Briefly describe each and explain the significance and limitations of the study.

Melatonin is found to be a powerful antioxidant. This is important for longevity and healing. The limitations of the study is that it may have not covered all the ways in which melatonin helps limit damage caused by free radicals (Reiter, Tan, Osuna, Gitto, 2000).

Melatonin receptor cDNA has been isolated from various specifies. This is significant in that it shows which genes are responsible for producing receptors in many animals, including humans. The limit is that it does not identify all such genotype and phenotype (Ebisawa, Karne, Lerner, & Reppert, 1998).

Write and answer two additional questions relevant to melatonin and the CNS.
What amino acid seems to be necessary for melatonin production?

Tryptophan necessary for melatonin production (Zwayer, n.d.). As such, a number of health related issues may occur as a result of not ingesting enough tryptophan, such as sleeplessness (Zwayer, n.d.).

What do you think would happen to melatonin production if someone had too much tryptophan?

If someone had too much tryptophan, melatonin production would increase (Zwayer, n.d.) and would lead to feelings of sleepiness (Zwayer, n.d.).

Melatonin and the Digestive System
Provide an overview of melatonin’s role in the digestive System?

In human digestive system, certain receptors have been identified, and melatonin performs a vital role digestive physiopathology (Zwayer, n.d.). The hormone may interact with receptors and produces hormones necessary for digestive system.
What other signaling molecules from within the digestive system come into contact with or affect melatonin? Explain.

The gastrointestinal tract (GIT) is the most important source of melatonin outside the brain (Martinetti, Scolaro & Obbia, 2008). Melatonin is released from the GIT wall where it is transported to body cells through the bloodstream. “In the upper portion of GIT, melatonin exhibits a wide spectrum of activities such as circadian entrainment, free radical scavenging lesions such as stomatities, esophagities, gasrtities and peptic ulcer” (Martinetti, Scolaro & Obbia, 2008).

Provide detailed information about how melatonin affects the digestive system. Include information on receptors, binding (if appropriate), what changes happen on the molecular in the presence of melatonin?

“1. Digestive system especially… [The] small bowel, highly effective in the biosynthesis of melatonin.

2. Melatonin, originating from the pineal gland, is responsible of nocturnal rise in plasma level…whereas that produce during the day-time originates mainly in theGIT.
3. Melatonin accumulates in the portal blood, and after metabolizing, its metabolites as well as the unchanged relation molecule are excreted in the bile.” (Martinetti, Scolaro & Obbia, 2008).

What changes happen at the tissue/organ level?

The presence of melatonin suggests that it is essential to digestive pathophysiology. ‘Melatonin in GIT is should to be generated in about 500 times larger amounts then it is produced in pineal gland….[M]elatonin in upper portion of GIT, including oral cavity, esophagus, stomach and duodenum, where this indole is generated and released into the GIT lumen and into the portal circulation to be uptaken, metabolized by liver and realized with bile into duodenum.” (Martinetti, Scolaro & Obbia, 2008).

How does the digestive system request melatonin when it is needed?

“There is a relationship between melatonin and food intake: abundant melatonin production in GIT, occurs mainly after good intake and maintains the indole concentration in peripheral blood, especially following the intake of high dietary protein rich in tryptophan, which serves as this indoleamine precursor” (Martinetti, Scolaro & Obbia, 2008).

Locate two clinical studies relevant to melatonin. Briefly describe each and explain the significance and limitations of the study. (No more than 2 paragraphs per study, please).

In one study, it was found G protein-coupled receptors for melatonin were cloned from mammals and named Mel1a melatonin receptor (Reppert, Godson, Mahle, Weaver, Slaugenhaupt & Gusella, 1995). The limit of the study is that it does not identify all such genotypic and phenotypic relationships with respect to melatonin.

In another study, it was found in humans that a photo pigment may be principally liable for melatonin being trapped in certain cells (Brainard, Hannifin, Greeson, Byrne, Glickman, Gerner, & Rollag, 2001).This is important because it identifies a primary component the biochemistry involved in retinal absorption of melatonin. The limit of the study is that it does not identify how this relates to the entire melatonin cycle.

Write and answer two additional questions relevant to melatonin and the digestive system.

What would happen to the digestive system if someone did not ingest enough tryptophan?

There would not be enough melatonin produced for effective assimilation into biochemical processes (Martinetti, Scolaro & Obbia, 2008).

What would happen to the digestive system if someone was not exposed to enough darkness?

As long as enough tryptophan was ingested, there may be no direct effect on the digestive system (Martinetti, Scolaro & Obbia, 2008). It is only in its absence that it would make for systemic problems.

Conclusion

Think of a metaphor for melatonin’s role within the body. Explain the metaphor and summarize melatonin’s role.

The Sun is the metaphor for melatonin’s role within the body. As we have seen earlier, light stimulates the secretion of melatonin within the body and light instigates the best option for the best secretion of melatonin. As the Sun sets and raises so do our levels of melatonin ebb and flow.

Explain how melatonin and the information presented in this questionnaire are clinically relevant.

This information is clinically relevant for a number of reasons. First, sufficient exposure to light and dark is in part responsible for stable health (Ehrlich, 2009). Furthermore, because melatonin production is dependent on tryptophan intake, people should make sure they are getting enough of it (Zwayer, n.d.). These two factors seem most important in melatonin production which regulates biorhythms in humans. Such biorhythms include the sleep and digestive cycles in everyone and reproductive cycles in women.

References

Barron, J. (2010). The Endocrine System: Hypothalamus, Pituitary, & Pineal Glands. Retrieved from http://www.jonbarron.org/natural-health/endocrine-hypothalamus-pituitary-pineal-gland

Brainard, G.C., Hannifin, J.P., Greeson, J.M., Byrne, B., Glickman, G. Gerner, E. & Rollag, M.D. (2001). The Journal of Neuroscience, 21(16): 6405-6412.

Buehler, L.K. (2003). Tissue specialization of amino acid metabolism. Retrieved from http://www.whatislife.com/reader2/Metabolism/pathway/Neurotransmitter.html

DiGiovanna, A.G. (2000). Melatonin Notes. Retrieved from http://www.biologyofhumanaging.com/Topics/mela_nt3.htm

Dubocovich, M. (2011). Modulatory role of melatonin in CNS function. Retrieved from http://www.labome.org/grant/r01/mh/modulatory/role/modulatory-role-of-melatonin-in-cns-function-6391918.html

Ebisawa, T., Karne, S., Lerner, M.R., & Reppert, S.M. (1998). Expression cloning of a high-affinity melatonin receptor from Xenopus dermal melanophore. PNAS, 9(13): 6133-6137.

Ehrlich, S.D. (2009). Melatonin. Retrieved from http://www.umm.edu/altmed/articles/melatonin000315.htm

Helmenstine, A.M. (n.d.) Melatonin Chemical Structure. Retrieved from http://chemistry.about.com/od/factsstructures/ig/Chemical-Structures—M/Melatonin.htm

Hsing, A.W, Meyer, T.E., Niwa, S., Quraishi, S.M & Chu, L.W. (2010). Measuring Serum Melatonin in Epidemiologic Studies. Cancer Epidemiology and Biomarkers Prevention: 19(4): 932–937.

Martinetti, F. Scolaro, S. & Obbia, S. (2008). Melatonin: a modular molecule. Retrieved from http://flipper.diff.org/app/pathways/info/1360

Reiter, R., Tan, D., Osuna, C., Gitto, E. (2000). Actions of melatonin in the reduction of oxidative stress. Journal of Biomedical Science, 7(6): 444-458.

Reppert,  S.M., Godson, C., Mahle, C.D., Weaver, D.R., Slaugenhaupt, S.A., Gusella, J.F. (1995). Molecular characterization of a second melatonin receptor expressed in human retina and brain: the Mel1b melatonin receptor. PNAS, 92(19): 8734-8738.

Zwayer, J. (n.d.) From tryptophan to melatonin to serotonin. Retrieved from http://home.bluemarble.net/~heartcom/tryptophantoserotonintomelatonin.html