Here is an article by Chris Bennett on Cannabis & the Power of the Pineal Gland ...
The pineal gland, located in the centre of the brain, is about a quarter of an inch in size, reddish-gray, and weighs about one-tenth of a gram. Unlike other parts of the brain which come in pairs, the pineal gland is singular. Its location in the center of the brain and presence in other species indicates it is an older part of humanity's evolutionary brain system.
The pineal gland is present in all lower vertebrae. In other species, like birds, reptiles and frogs, the pineal gland is called the parietal eye or "third-eye" as its functions closely resemble that of an actual eye. In these other species, the pineal gland has components of an actual eye, with a cornea, rod and cone. It is considered to be the vestige of a functional sense organ of early primitive vertebrates.
Directly affected by the light taken in through the eyes, the pineal regulates sleep, menstrual cycles, mating seasons, hibernation, seasonal flight patterns and many other "instinctual" behaviors.
Psychedelic researcher Dr Rick Strassman has explained how the pineal gland "is quite active in synthesizing compounds related to serotonin, an important neurotransmitter in the brain. Neurotransmitters are the chemical messengers allowing communication among individual nerve cells. Most typical psychedelic drugs, such as LSD, mescaline, psilocybin, and DMT are active in brain sites which are also affected by serotonin. In addition, most of these drugs are similar in their chemical structure to serotonin."
Strassman states that most of the above substances belong to the "tryptamine" class of drugs, and proposed that the pineal gland produces "one or two endogenous tryptamines found in human blood and cerebrospinal fluid. This latter fluid continually bathes the brain, and compounds found in it most likely affect brain function."
Strassman also explains how "psychedelic drugs, meditational states, spontaneous near-death experiences and other phenomena which may induce stereotypic death/rebirth and paradisal/hellish states act via the pineal gland.
Lyttle points to the universal mystic vision of God as an all-consuming white light, and postulates that on a physiological level, this experience is produced from chemical reactions in the pineal gland which is extremely light sensitive. "Light, the eyes and the 'third eye' or pineal gland form a triad which directly controls and regulates normal or altered consciousness and many bodily functions? these three factors are also directly related to, or implicated in, mystical states and the 'psychedelic' experience."
Visions of white light are not only associated with mysticism and psychedelic explorations, but are also a prevalent image recorded by those who experience the near-death state. A reason for this recurring theme in near-death states may be found with Dr Strassman, who suggests that after death, as the pineal gland shuts down, some of the chemical present in it may turn into "psychedelic" drugs!
According to Dr Strassman, the pineal gland may not only play an important role in death, but also in birth, possibly even in rebirth...
The pineal gland first becomes visible in the human fetus at the same time as does the clear differentiation of the fetus into female or male gender. The time for both of these events is 49 days, the period of time that, according to several Buddhist texts, the life force of a deceased individual coalesces around its next corporeal existence. If the life force does indeed enter through the pineal, the manifestation of this coming and going would be the release of psychedelic tryptamines, which would mediate the visionary experiences associated with near-death, and near-birth states.
Certain initiatory cults, such as Tantrism, Kundalini and Gnosticism, acknowledged the role of the pineal gland in the spiritual process. The spiritual/instinctual life force was seen as a serpent, due to its physical structure extending from the genitals, through the spine and up into its single all-seeing eye in the pineal gland.
These spiritual systems focussed around the raising of this primordial serpentine energy, based in the genitals and at the core of the pro-creative process. Through certain yogic practices this energy can be reversed and forced to travel up the spine into the brain, where it is reputed to cause "enlightenment".
In the Kundalini system, which has seven distinct energy centers, the pineal gland has been variously identified with the "Ajna Chakra" and alternatively the "Sahasrara Chakra". Both pre-Christian Mithraic and second century Gnostic texts also distinctly refer to the pineal gland in relation to seven distinct energy centers and this serpentine energy.
Not surprisingly, a common experience of those who have successfully raised their kundalini is the vision of all-consuming white light. More importantly, the devotee who successfully raises the kundalini experiences a radical switch in consciousness, obliterating the sense of individuation, and enters Nirvana.
Another potential reference to this curious little gland may occur at the end of the New Testament book of Revelation, where we find that the elect will know God intimately, "his name will be in their foreheads," which is where the pineal deeply lies. Noting the gland's strong connection with light, the rest of the passage is interesting: "There will be no more night; they will not need the light of a lamp or the light of the sun, for the Lord God will give them light."
Likewise in the Qabalistic tradition, the primordial archetypical man, Adam Kadmon, shines forth with a light from his forehead that was rich in complex patterns and linguistic symbols. Similar imagery occurs in the Persian tradition of the light-like sacred fluid, the "vivifying and spermatic" xvarenah. "Ahura Mazda is preeminently the possessor of xvarenah, but this 'flame' also springs from the forehead of Mithra and like a solar light emanates from the heads of sovereigns."
This mind-light from the forehead is also identical with the 3rd Eye of Shiva, which when opened in the individual burns away the concept of ego-bound consciousness, and when opened collectively has the potential to burn away the ties and fetters of the Old World Order.
Perhaps if enough modern psychonauts achieve the pineal experience we can push this new frame of mind onto the rest of ego-bound humanity. Here at the turning of the millennia, in the apocalyptic year of 1999, never has the potential for the state of mind which has been the goal of yogic sages, and psychedelic voyagers alike been so possible to attain for humanity as a whole.
Source: Psychedelic Adventure