Can you imagine the tiny, pea-sized pineal gland in your body can hold immense power? Well, it can!
Situated between the 2 hemispheres of brain, this endocrine gland is associated with controlling the human body’s biological rhythms. It is composed of the lobular parenchyma of pinealocytes, which make up the major portion of it. Its primary function is to secrete the sleep hormone called melatonin.
Short note on structure and function of Pineal Gland
Anatomy of the Pineal gland!
Pineal gland develops from the bottom of the diencephalon and is located behind the third cerebral ventricle. In adults, pineal gland weighs about 0.1 gm. and is 0.3 inches long. This gland has adrenergic nerves which influence its function. A significant portion of this gland is composed of pinealocytes and astrocytes.
Although this pineal gland exists in most vertebrates, there are certain exceptions like hagfish. Another existing relative to vertebrates lacking a pineal gland is lancelet Branchiostoma lanceolatum.
From the viewpoint of biological mechanism, this gland is an atrophied photoreceptor; meaning, it is linked to a light sensing organ known as ‘third eye’ or parietal eye.’
According to famous philosopher Rene Descartes, pineal gland is perceived to be “the principal seat of the soul.” Even though, in science, it doesn’t have any such metaphysical qualities, in the field of pseudo-science, this gland continues to possess an exalted status.
Cellular structure of the pineal gland
The pineal gland is composed of various kinds of cells, each varying in their structure; the most dominating cells being Pinealocytes. Their primary function is secretion of the hormone melatonin.
Further, this gland is subdivided into many capillaries containing perivascular phagocytes; these phagocytes are responsible for antigen formation.
Following are pineal neurons present in most vertebrates except certain rodents. Its last cells are the peptidergic neurons that have regulatory functions.
Nerve supply of the pineal gland
Nerve fibers stimulating the pineal gland in mammals originates in perikarya and are located in these 3 areas-
- Otic ganglia
- Parasympathetic sphenopalatine
- Sympathetic superior cervical ganglion
These nervous fibers consist of neuropeptide Y and norepinephrine which act as neurotransmitters. The parasympathetic nerve fibers possess peptide histidine isoleucine and vasoactive intestinal peptide. The neurons in the trigeminal ganglion comprising pituitary adenylate cyclase-activating peptide, substance P, and calcitonin gene-related peptide, affect the mammalian pineal gland.
The functions of pineal gland are as follows:
There are notably 2 main functions of the mammalian pineal gland –
- Regulates the body clock.
- Controls the reproductive hormones in the human body.
Pineal gland and Melatonin production
Melatonin, secreted by the pineal gland, is also called the darkness hormone. The reason is this hormone starts its production from dusk and keeps secreting till dawn. With the cessation of night, this gland stops production.
This melatonin produced induces sleep and further helps to protect a body from the following-
- Cardiovascular issues- hypertension and atherosclerosis
- Headaches and migraines
- Cancer and unnecessary pains in the body
Few interesting facts about the hormone melatonin
- Melatonin is also known as the body’s natural pacemaker. It plays a vital role in maintaining the body clock by signaling a time of year and time of day.
- Shift workers, to maintain their body’s internal clock, often take melatonin to escape insomnia and treat jet lag.
- Studies conducted showed that blue light inhibits production of natural melatonin; hence, it is considered melatonin’s archenemy. Whereas, red light is associated with enhancing melatonin production. Therefore, red lights are the ideal option for night-lamps.
- Melatonin production is the strongest 2 hours before going to Hence, a person with a dedicated sleep schedule falls asleep at the same time each day.
- This hormone plays a central role in regulating the female menstrual cycle. It governs the hormones affecting the onset, duration, and frequency of the cycle; all through their life.
- Melatonin supplements are not sleeping pills, but they do help in inducing slumber.
- Melatonin production is not only affected by different types of lights but also by its varying degrees. There are light sensitive receptors in the brain which trigger hormone responsible for melatonin secretion. These receptors depending on the intensity of the light, secrete the hormone.
- It acts as a neuroprotector which helps to slow down ageing. Moreover, due to its autoxidizing properties, it helps to treat Alzheimer’s disease (AD).
- This hormone helps children facing ADHD, as researchers showed that melatonin could decrease sleep onset latency. This is the amount of time taken by a person to go from the state of wakefulness to sleep.
- Melatonin production is dependent on age. It increases once an infant reaches 3 months and peaks when the child is 6, and diminishes at puberty.
What is the prescribed dosage for using melatonin supplements?
There is no such correct dose of melatonin supplements. However, the prescribed dose ranges from 0.3-0.5 mg for sleep promotion. Patients undergoing cancer treatments, however, utilize 3-50mg of doses but this should be considered only under a doctor’s recommendation. You can check here the melatonin dosage for kids.
Side effects and considerations while using melatonin sleeping aids
Side effects –
- Decreased body temperature
- Daytime Lethargy
- Increased irritability and crankiness
When to avoid using melatonin –
- Pregnant and breastfeeding women – It can react with the hormonal changes adversely.
- People with psychiatric medication – It might react with the drugs negatively.
- Women showing pre-menopausal tendencies – Melatonin inhibits symptoms of ovulation in women.
- Those suffering from auto-immune diseases – The supplement reacts with the body negatively.
- Diabetic patients – These aids increase blood sugar levels in the body.
How to take melatonin correctly?
- For use as a general sleeping aid, take 0.3-10 mg.
- For restless leg syndrome, not more than 3mg.
- To combat jet lag, a dosage of 0.5-8 before going to bed.
- For insomnia in adults, 0.5-5 mg is the prescribed choice of doctors.
What not to take with melatonin?
Two things can affect the sleep-wake cycle – alcohol and caffeine; hence, one should avoid these while consuming these supplements.
Moreover, before you take melatonin supplements it’s best to consult a doctor, especially if one is under other medication or birth control pills. Birth control pills, in general, increase melatonin production. So, taking a supplement can lead to the unhealthy secretion of this hormone.
In conclusion, it is still unclear what the relation of melatonin and pineal gland is. This hormone as mentioned regulates the wake-sleep pattern and has shown to benefit in treating various other ailments, besides sleep. Scientists are presently trying to find a more conclusive relation between melatonin supplements and their uses.