Melatonin Essay

Introduction to Melatonin

Melatonin1, a neurohormone that is synthesized in and secreted from the pineal gland, is a circadian cycle regulator, affecting when to sleep, wake up, eat, and so on. One’s circadian rhythm is affected by factors such as sunlight and temperature, and has more recently been studied in relation to light from electronics. Synthetically produced melatonin’s purpose is often misconstrued as being a sleeping aid, however its main purpose is to regulate circadian rhythms, and is commonly used as an anti-migraine medication as well.

Melatonin was first discovered in connection to the mechanism by which some animals change the color of their skin. It was later named melatonin, and linked with the circadian rhythm in humans

When melatonin is bound to an MT1 receptor, it results in an inhibition of neuronal firing, which is thought to mediate the sleep promoting effect of melatonin. Activation of this receptor inhibits cAMP formation and phosphorylation of the cAMP. It potentiates vasoconstriction by blocking calcium-activated potassium channels in smooth muscle due to decreases in cAMP, which decreases motor activity and induces fatigue by lowering body temperature and blood pressure. Studies on MT2 have not been conclusive in determining the relationship between sleep and melatonin, other than reinforcing the inhibition of cAMP signaling.

Melatonin’s analgesic effects on migraines involve β-endorphins, GABA receptor, opioid receptors, and the nitric oxide pathway (https://www.ncbi.nlm.nih.gov/pubmed/27698681). Melatonin was found to increase K+ currents; because K+ channels are able to produce antinociception, the idea is that melatonin could open these K+ channels and therefore assist in the production of antinociceptive effects has been studied thoroughly

When taking too much melatonin, the subject’s body thinks it no longer needs to produce melatonin, subsequently causing it to become dependent upon the artificial melatonin due to decreased natural synthesis. The proper dosage, according to one study, is 0.3 milligrams; yet, over-the-counter doses are often much larger. This can lead to higher plasma melatonin levels the next day, which can cause users to feel groggy. In migraine-prone subjects, this grogginess may also be a migraine trigger. However, another study showed that “90% of orally administered exogenous melatonin is cleared in a single passage through the liver, a small amount is excreted in urine, and a small amount is found in saliva,” alleviating common concerns regarding excess melatonin within one’s body after taking too large of a