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Lit from Within: An introduction to ancient and modern perspectives of the pineal gland By Sarah Tewhey These same insrtuctions can be heard in mediation center, prayer groups and more recently in Western hospitals around the world. But what is it that allows this turning to take place, and as we make this motion what exactly do we come to face? According to ancient wisdom we turn to a plce deep within the center of the head, a place where the individual meets the universal, where day meets night, where light meets dark. This place has many names and its long history spans both distance and culture. It is best known today among spiritual seeker as the third eye. As modern research marches forward and the east/west exchange deepens an emerging connection between this mystic 'third eye' and the pineal gland is beginning to take shape. Anatomy and physiology The pineal is a neuroendocrine gland that resides deep within the portion of the brain known as the diencephalon in the epithalamus (Marieb, 2001). This tiny gland, roughly the size of a grain of rice remains untouchable and well protected deep within the brain tissue. The pineal gland is the only unpaired organ in the brain (Saraswati, 1973) and is composed of specialized cells known as pinealocytes. It literally hangs from the top of the third ventricle, arranged just superior to the spinal column in nearly the center of the head (Marieb, 2001). This small and carefully guarded gland receives a supply of blood that seconds only that of the kidneys (McMillin, 1991). Although not a direct light sensing organ in mammals, the pineal gland relies on light for information involving hormone production. For this reason the pineal gland and the eyes are intimately connected. The pineal gland receives information through photoreceptors in the eyes via a roundabout route that leads from the retina, to the suprachiasmatic nucleus of the hypothalamus, to the superior cervical ganglion and then to the pineal gland (Marieb, 2001). This path is abnormally long when compared to other routes leading from the eyes that go almost directly to visual processing centers toward the back of the brain. Information regarding natural lighting conditions travels from the retina of the eye to a particular area of the hypothalamus that acts as a biological timer. Light from the eyes is one source of information that keeps the suprachiasmatic nucleus in the hypothalamus running smoothly. From here the information regarding the length and the intensity of daylight travels to the superior cervical ganglion, a nerve bundle at the very top of the spinal column. These nerves help to control the blood and skin of the head, pupil dilation and the lifting of the eyelids. From this nerve bundle the information finally reaches the pineal gland (Marieb, 2001). In a human embryo, the pineal gland begins its formation at roughly seven weeks. This development closely corresponds to the appearance of gender. The pineal is not created from brain tissue, but emerges from a specialized tissue at the roof of the mouth. It is from this point that the fetal pineal gland travels to the center of the head (Strassman, 2001). Interestingly, in some yogic pranayama, the tip of the tongue is held at the roof of the mouth in order to create a mood of attention, awareness and serenity (personal notes, 2001). This position of the tongue is also said to regulate the movement of the cerebrospinal fluid and facilitate the release of 'bliss' molecules (Lad, 2002). Because the pineal gland does not develop from brain tissue it is exempt from the rules of the blood brain barrier that keeps the brain safe from blood impurities. Despite this, there are 'clean up' nerves around the pineal that protect it from certain substances in the blood. Among these are the hormones epinephrine and norepinephrine. These two hormones are known to modulate stress response in the body and are connected to the sympathetic nervous system (Strassman, 2001). Because these stress hormones do not effect the pineal gland in the same way as other endocrine organs, it may be possible that the pineal remains without a burden of stress and is consistently in a more relaxed state than the rest of the body. This idea has interesting implications based on the ancient views of the pineal gland described in following sections. The most well understood hormone of the pineal gland is melatonin. This hormone is known for its relationship to circadian rhythm. It rises in response to the onset of night and tapers off at daylight. Melatonin is created in the pineal gland from the amino acid tryptophan, which is then converted into serotonin. The pineal gland produces the neurotransmitter serotonin during the day and as night comes, chemically changes the serotonin to melatonin for distribution throughout the body (Hilton, 2003). Receptors for melatonin are concentrated in the suprachiasmatic nucleus of the hypothalamus, in the anterior pituitary, in the retina (Marieb, 2001) and are slowly being discovered throughout other parts of the brain and body. Recently scientists discovered that the pineal gland participates in 'biodirectional communication' with the immune system (Skwarlo-Sonta, 2003). Spiritual aspirants have long understood this particular mind/body connection (personal notes, 2001) and the research community is now actively at work proving this ancient knowledge. Melatonin receptors have recently been discovered in many lymph organs and immune cells indicating that this hormone directly affects immune function. In conjunction to this the pineal gland apparently picks up messages sent by immune cells in a complete feedback cycle (Skwarlo-Sonta, 2003). While the mechanisms and purposes of this transaction are not yet understood the discovery itself will hopefully inspire the evaluation of melatonin's effects on the body as an integrated system. The presence of melatonin increased humoral and cell-mediated immune function in research with hamsters. When injected into mice melatonin has been found to increase a number of chemicals related to the immune system including interleukins and interferon. When a pinealectomy was performed a marked reduction in antibody activity was found. These studies are uncovering melatonin's important, if not well-understood relationship to the immune system (Hilton 2003). Because of its relationship to cycles of light and darkness melatonin affects the bodily processes relating to circadian rhythm. Among these are the cycles of wakefulness and sleep. While not directly inducing sleep, melatonin appears to inhibit wakefulness. Insomniacs and individuals suffering from jet lag have both benefited tremendously from a dietary supplement of melatonin (Hilton 2003). This hormone has also been found to aid the function of the heart via its anti-platelet and anti-hypertensive effects. There is a close correlation between increased melatonin production and decreased risk of myocardial infarction (EECP Center of Northwest Ohio, n.d). Melatonin also appears to have anti-aging effects. Its levels are highest in childhood and begin to decrease just prior to the onset of puberty (Hilton, 2003). As humans grow older melatonin production slowly decreases. Due to this decrease ATP production within the cells also decreases creating an imbalance in energy production. With this comes the slow calcification of the pineal gland. At this point a substance known as 'brain sand' begins to develop. Brain sand is created during the aging process as molecules containing calcium salts begin to form. This creates granulation in the gland (EECP Center of Northwest Ohio, n.d.). Due to brain sand's material substance it shows up brightly on MRIs and X-rays. For this reason the pineal gland has become the reference point in the brain when reading these images (Marieb, 2001). The appearance of brain sand is literally the beginning of the aging process as the pineal gland is the first human organ to calcify (EECP Center of Northwest Ohio, n.d.). Calcification of the pineal gland is seen in most Americans by the age of 50. There appears also to be a relationship between the onset of calcification and cancer. Interestingly, cultures that spend more time in natural lighting and consume unrefined foods seem to have a lower incidence of pineal calcification (Colorado State University, n.d.). While sunlight and darkness naturally regulate melatonin each day, artificial lights do not have the same effect as daylight on the production of this hormone. Artificial lights do not have the ability to stop the production of melatonin during hours of darkness (Hilton, 2003). This information raises many questions regarding the effects of artificial light on the pineal gland and melatonin. Apparently, the artificial lighting of modern man does not fool the pineal. It may in the future be found that the natural circadian rhythm and the presence of abundant artificial light are causing conflicting signals. If this is found to be true it may help to explain the increased incidence of depression, heart attack, sleep disturbances, cancer and reproductive disorder s in the United States. While purely speculative, this is an area that deserves attention and research. Evolutionary History In many animals including other mammals the biological effects of melatonin are far more pronounced than those found in humans. Many animals that have a particular season for reproduction are alerted to the onset of the breeding season by the length of the day. Melatonin is known to be anti-gonadotrophic. Long and bright days of sunshine cause a decrease in melatonin production, thus stimulating breeding. Shorter days and longer nights increase melatonin secretion and signal the body that the breeding season is ending (National Institute of Health, n.d.). Circadian rhythm in house sparrows also contributes to the proper timing of behaviors such as migration, feeding, nest building and communal huddling (Hilton, 2003). It appears that the pineal gland at one time in evolutionary history actually did function as a third eye for many animals. This feature remains in a few species today. The Western Fence Lizard, the Pacific Tree Frog and the Pacific Sea Lamprey, are three classic examples of animals that have active pineal glands which also function as a third eye. In all three of these animals the pineal rests at the very top of the head above the brain and still has photoreceptive components for vision (McClay, 1976). Some eastern spiritual teachers say that as humans evolved and relied less on instinct and more on intellectual ability for survival that the sympathetic nervous system fell into the background as the central nervous system developed. Because yogic texts associate the sympathetic nervous system with the pineal, this small gland over time also took a less prominent role and receded into the head (Saraswati, 1973). It appears that the pineal gland in humans slowly is decreasing in size and was at one time a larger and more prominent organ. The human pineal is connected to the cerebellum, one of the most ancient parts of the human brain, responsible for coordination (McClay, 1976). At one point the human pineal gland probably did contain cells that were active photoreceptors. This era for the human pineal gland has passed and the gland now relies on the photoreceptors of the eyes and the processes of the sympathetic nervous system for its information (Saraswati, 1973). Ancient Knowledge Around the world there seems to be common mystical knowledge of a transcendent area that lies between the eyebrows in the center of the head. This ancient understanding miraculously appears in traditions and cultures around the world spanning thousands of years. How such a global realization could have emerged is both puzzling and fantastic to contemplate. While belief varies slightly between traditions, the position of the pineal gland in the head corresponds closely with what is commonly known of as the third eye. Across cultures it is an area of spiritual insight and connection with universal consciousness. One religious scholar, Rev. Dr. Mobiustrip speaks of the connection between 'pineal', the word in Latin given for it's pinecone like shape and the ancient Hebrew word 'p'nay el' which translates as 'the face of God'. This word is found early in the Torah in Genesis 32:21(Mobiustrip, n.d.). While there is no direct evidence that this is any more than a coincidence, it is well known that the Hebrew language in the Kabalistic sense is imbued with meaning. Each character and their combinations can be interpreted and contemplated to yield insight. Because words in the Hebrew language are deliberate and complex, there is a chance that this connection between pineal and p'nay el has a history that is yet undiscovered (personal communication with Yonatan Yoshpe, January 2, 2003). Ancient dialogues between teachers and students in the Chinese Taoist tradition show insight into the subtle function of the third eye and describe its exact location. In one such text the master Liao Jan states, "It is (in the center of the brain behind) the spot between the eyes. Lao Tze called it "the gateway to heaven and earth", hence he urged people to concentrate on the center in order to realize the oneness of all things." (McClay, 1976) Buddhists temples often place a precious jewel at the point of the third eye and the ancient Egyptians and many Native American tribes place special ornaments or designs in their headdresses at this sacred site on the forehead (Saraswati, 1973). Rick Strassman (2001), author of DMT: The spirit molecule briefly raises an interesting note regarding the influence the pineal gland plays in sexuality and spirituality. The pineal gland is known in the West to have an influence on the maturation of secondary sex characteristics and is responsible for the reproductive cycle of other mammals. While the pineal gland is known to have a role in sexuality, it has been believed in ancient cultures to play a role in human spiritual experience and enlightenment. These are two areas that have been linked over time and across traditions. In many cultures, those seeking spiritual knowledge turn to a life of celibacy or sexual restraint. Contemplative studies have uncovered close connections between the ancient yogic system of energy centers known as the chakras and the modern endocrine system. In the yogic tradition of India the location of the pineal gland bears a correlation with that of the Ajna Chakra. This chakra is understood to be the center of intuition, psychic awareness, siddhis, higher states of consciousness and connection to universal energies (Saraswati, 1973). Swami Sivanand taught, "The pineal gland is the receptor and sender of the subtle vibrations which carry thoughts and psychic phenomena throughout the cosmos. The pineal gland converts brain waves into subtle electrical energy traveling faster that the speed of light and which are stored by the individual brain." (Saraswati , 1973) Meditators with some experience sense that a long-term meditation practice somehow shifts the functioning of the pineal gland and the nervous system (Saraswati, 1973). In the recent article On a possible psychophysiology of the yogic chakra system by Dr. S.M. Roney- Dougal (1999) the pineal gland is paired with the pituitary gland in a 'command' role. The root of the word 'ajna' in Sanskrit is 'to know, obey and follow'. Dr. Roney- Dougal suggests that while the pituitary acts as a stimulator for the other endocrine glands, the pineal may acts as an inhibitor. This would give the pineal gland a crucial role in the regulatory function of every other endocrine organ in the body, and thus an ability to control and influence the six other chakras. Early Scientific Inquiry The pineal gland emerges throughout history in the writings of physicians and philosophers alike. The Greek Physician Herophilus wrote of discovering the small gland in the third-century B.C. (Strassman, 2001). The Greek physician Galen in the 2nd century A.D. also wrote of the presence of the pineal gland. Galen's belief was that the gland most likely was related to the movement of thought between hemispheres of the brain (McClay, 1976). Rene Descartes is perhaps best remembered for his writings on the role of the pineal gland. In the 1600's Descartes called the pineal gland the 'seat of the soul' and made a connection between the function of the eyes and the pineal via a network of 'strings' in the brain. He theorized that the pineal might interpret visual stimulus in order to create reaction by the muscles (McClay, 1976). From Herophilus forward the theories and arguments regarding the function of this tiny organ were varied, at times heated and interesting to say the least. The commonly held belief was that the pineal acted as a valve through which the spirit passed in order to activate different areas of the brain. Scholars even went so far as to describe how the spirit could be moved to different areas of the brain by tilting the head in various directions. The speed at which the spirit was able to move through the valve explained why some men were quick and clever and others slow and dimwitted (Lokhorst, Kaitaro, 2001). The pineal became a member of the endocrine system in 1898 by scientist Otto Heubner who also sited the pineal's connection with the onset of puberty (McClay, 1976). In 1927, scientists Carey Pratt McCord and Floyd Pierpont Allen performed a now famous experiment with tadpoles. The scientists found that when crushed pineal glands were added to water, tadpoles introduced to the mixture would inexplicably lighten in color. Despite this interesting effect little research was done until the 1950's when discoveries at major universities began to find relationships between the pineal gland, reproductive function and the presence of natural light. In 1958 Aaron Lerner at Yale University isolated the pineal's still only known hormone, melatonin (National Institute of Health, n.d.). In the later part of the 1950's Julius Axelrod, one of the pioneers in the field of neuroscience took an interest in the pineal gland. He began a series of studies that would span over fifteen years. Axelrod along with several fellow researchers discovered the link between melatonin and serotonin and contributed to the knowledge that melatonin acted as a biological clock (National Institute of Health, n.d.). After many years of belief that the pineal gland was an outdated and nonfunctioning human organ, these twentieth-century scientists took the pineal gland 'off the shelf' and opened up a critical new area of human research. Modern Research and Theory Compared with other glands there is still comparatively little known about the pineal. Research continues, speculation abounds and slowly but surely a picture of the pineal gland is beginning to emerge. In the mid-eighties connections between the pineal and the brain were discovered via tiny nerve fibers running through the posterior commissure and the habenula, two areas of the brain that govern coordination of the left and right hemispheres, sleep and mood (Pineal gland speaks to the brain, 1986). This research provided evidence that the pineal gland and the brain were in fact in direct communication. Studies have also shown that removing the entire eye or severing the nerves between the eyes and the pineal causes melatonin function to cease. Visual science has long shown that there are two photoreceptors in the retina known as the rod cells and the cone cells. Rod cells are activated in dim light while cone cells are stimulated by bright light and color. It was previously thought that through these photoreceptors all visual information was relayed to the brain. Recently studies with mice have shown that if the eyes remain intact and only the rod and cone cells are degenerated that pineal function continues as normal (Lucas, Freedman, Munoz, Garcia-Fernandez, Foster, 1999). This piece of research indicates that there are other groups of photoreceptors in the eyes besides the rod and cone cells. While scientists do not yet have a clear picture of what these new non-image photoreceptor cells may be, their presence may help to explain physiological puzzles such as blood pressure, pupil size, attention and mood which are all affected by environmental light (Lucas, Freedman, Munoz, Garcia-Fernandez, Foster, 1999). Recent research is also beginning to indicate a relationship between the presence of melatonin and the suppression of tumor growth. Removal of the pineal gland has been shown to promote the growth of tumors and metastasis, specifically in the breasts and the ovaries. Conversely, melatonin seems to inhibit certain types of cancer cells and may activate genes that suppress tumors. Studies are also showing that an extract of the pineal gland itself yields better results than melatonin alone, indicating that there may be other substances created in the pineal gland that are yet to be discovered (Hilton, 2003). This exciting information in conjunction with research linking melatonin and the immune system could yield highly effective and innovative treatments for cancer in the future. In Conclusion The pineal gland's history in the context of the human experience dates back many thousands of years and crosses ancient and modern cultures worldwide. Perhaps by observing remnants of a third eye in local animals or by deep spiritual practices individuals and communities were able to evaluate their own bodies in an similar, accurate and meaningful way. Today our instruments and experiments can measure the slightest chemical nuances of physiological processes. This brings understanding where there once were no explanations and emerging evidence where there once was only speculation. What our research lacks however is insight into what is unseen and what cannot be measured; meaning, wisdom and a more holistic understanding of our place in the universe. By honoring the intuitive knowledge of those that have come before us and continuing with the finite pursuits of modern science our logic will mesh with intuition, microcosm becomes macrocosm, individual becomes universal and night melts into day. Bibliography Colorado State University. (n.d.). The pineal gland and melatonin. Retrieved on November 10, 2003 from http://www.arbl.cumbs.colostate.edu. EECP Center of Northwest Ohio. (n.d.). Brain sand. Retrieved November 6, 2003, from http://heartfixer.com/Brain_sand.htm. Hilton, G. (2003). Melatonin and the pineal gland. Journal of Neuroscience Nursing, 34(2), 74-80. Retrieved on November 6, 2003 from Academic Search Premier. Lad, V. (2002). Textbook of ayurveda: Fundamental principles. Albuquerque: The Ayurvedic Press. Lokhorst, G.J.C., Kaitaro, T.T. (2001). The originality of Descartes' theory about the pineal gland. Journal for the History of the Neurosciences, 10, 6-18. Retrieved on November 2, 2003 from http://web.eur.nl/fw/staff/lokhorst/pineal.htm. Lucas, R.J., Freedman, M.S., Munoz, M, Garcia-Fernandez, J.M. and Foster, R.G. (1999). Regulation of the mammalian pineal by non-rod, non-cone ocular photoreceptors. Science, 284(5413) 505. Retrieved on November 1, 2003 from Academic Search Premier. Marieb, E.N. (2001). Human anatomy and physiology (5th ed.). San Francisco: Benjamin Cummings. McClay, R. (1976). The pineal gland LSD and serotonin. Retrieved November 6, 2003, from http://www.serendipity.li/mcclay/pineal.htm. McMillin, David. (1991). The pineal. The Treatment of Schizophrenia. (Appendix B). Virginia Beach, VA: A.R.E. Press. Retrieved on November 14, 2003 from http://www.meridianinstitute.com/mh/pineal.html. Mobiustrip, Rev. (2002). From the face of god to the seat of the soul. Retrieved on December 20, 2003 from http://www.the44net/blog/pineal.htm. National Institute of Health: National Library of Medicine. (n.d). The pineal gland and the melatonin hypothesis, 1959-1974. Retrieved on November 6, 2003, from http://profiles.nlm.nih.gov/HH/Views/Exhibit/narrative/pineal.htm. Pineal gland speaks to brain. (1986, Feb22). Science News, 129, 122(1). Retrieved November 6, 2003, from Lesley University, Health Reference Center - Academic. Roney-Dougal, S.M., (1999). On a possible psychophysiology of the yogic chakra system. Journal of Indian Psychology, 17(2). Retrieved on December 20, 2003 from http://www.yogamag.net. Strassman, R. (2001). DMT: the spirit molecule. Rochester, VT: Park Street Press. Saraswati, S.N. (1973). Ajna chakra. Bihar, India: Bihar School of Yoga. Retrieved on December 20, 2003, from http://www.beezone.com. Skwarlo-Sonta, K. (2003). Biodirectional communication between the pineal gland and the immune system. Canadian Journal of Physiology and Pharmacology, 81(4), 342-349. copyright 2004 ------------------------------------------------------------ Sarah Tewhey is a student and teacher of Yoga, Ayurveda and the healing arts. She completed two years of study with Dr. Vasant Lad at The Ayurvedic Institute and a B.S. at Lesley University in Mind/Body Studies with a specialization in the female healing process and its relationship to modern medicine. Sarah is currently a student in the Masters program at Southwest Acupuncture College in Albuquerque. Sarah can be contacted at: sarah@ayurlight.com |
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