Ouroboros represents a number of things consistent with the serpent: regeneration, rebirth, cyclical nature, wholeness, wisdom, enlightenment. Its circular configuration reinforces qualities already generally associated with the positive interpretations of the serpent that are nearly universal among traditional cultures.

Mythology - The Serpent as Divinity

India
The Aitareya Brahmana states that the serpent Ahi Budhnya is invisibly what Agni, [the 'furious serpent'] is visibly. In other words, the serpent is a virtuality of fire, whereas darkness is nonmanifested light. Again, when the sun rises at dawn, he 'frees himself from night ?just as Ahi frees himself from his skin'.
It is in India where we again meet the significant divine serpent in many aspects. In India the cobra has long been considered sacred, and even those cobras used by 'snake charmers' are not injured in any way, not defanged, and when they are used for while they are safely returned to the wild. The "Naga" which is the divine aspect of the cobra is found in both Hindu and Buddhist traditions. In some passages, King Varuna is regarded as being among the most preeminent of the Nagas, and he is included in the discussion of these mythical divine serpents. [Mahabarata 1.26.1. and 25.4] The 'naga' is a divine serpent who is a son of Kadru, the daughter of Daksha.
The word naga is a Sanscrit word which means "serpent". Nagas are believed to live in palaces [Patala] in the underground city Bhogavati. They are considered the protectors of springs, wells and rivers. They bring rain [ similar to the Chinese Lung dragons] and therefore fertility, but can also bring disasters such as floods and drought. In Malay myths nagas are many-headed dragons of enormous size. On Java and Thailand, the naga is a serpent-god, a ruler of the netherworld who possesses much wealth. In Java they are also called Sesas. In Thailand the naga can have five heads, much like the Hindu Naga Kanya.
In Mexico we find the word "Nagal" which describes a class of serpent guardian spirits. The avenue leading to the main temple at Ankhor Wat is lined with seven-headed nagas. The Chinese claim to be able to speak Naga-Krita, the language of the serpentine gods. For a place that has no serpents, Tibet, the naga are still known in a symbolic sensand are called "Lu' which is the Tibetan translation of " naga". For example Nagarjuna is called Lu-truh in Tibet.
The Naga represents cosmic power; they are a manifestation of the Vedic god Agni, or fire, and as such becomes the 'fierce spirit' who is the guardian. The cobra/naga is a mount of Vishnu and as such represents knowledge, wisdom and eternity. As Vishnu sleeps on the cosmic ocean, he sleeps on the coiled serpent on the primordial waters. Two serpents with downward and upward movement represent the divine sleep and divine awakening. The Naga and Nagni are serpent kings and queens, which are divine in their own right. They are depicted as either fully human, fully snake, humans with cobra heads and hoods, or as humans from the waist upwards and snake below that.
The naga as a god is widespread and significant in all of Southern Asia. As far away as the Malay peninsula we find Raja Naga, or King Naga. Who is the king of all of the many sea snakes which populate the area. In India the chief function of the naga is apparent in temple architecture; they guard the doors.
Vishnu, the preserver aspect of the Trinitarian Brahma principle, is recognized as one of the most important and most revered of the deities of the Hindu pantheon. He is most often depicted as reclining on a the coils of the great serpent. The Great Naga, Ananta [ the 'endless'], also called Sesha. Ananta has 1000 hooded heads which form a canopy for Vishnu. Ananta represents the cosmic ocean.
The symbol for water, in Hindu mythology, is the serpent [naga]. So that, not only the gigantic anthropomorphic form and the boundless elemental sea are Vishnu, but the naga is also Vishnu. He is man, ocean and snake. All are one. Springing forth from the navel of Vishnu is a lotus stem, and on the flower at the end of the stem sits the god Brahma who creates the world. Ananta spits out venomous fire at the end of each Kalpa [age] to assist Shiva in destroying the creation.
Nagas are recognized as superior to humans. They inhabit subaquatic paradises, dwelling at the bottoms of rivers, lakes and seas. A most important function of these divine serpents is their function as guardians. We find them at the doors of Hindu and Buddhist shrines. They van not only frighten ordinary human intruders with their dangerous aspect as cobras, they can as divinities, discern and repel any divine invader.

Krishna tells Arjuna all about 'divine' serpents. [ Bhagavad-Gita Ch. 11].

The Cosmic Serpent:
DNA and the Origins of Knowledge
Narby, Jeremy (1999)
New York: Jeremy P. Tarcher/Putnam
ISBN: 0-87477-964-2 paperback

Excerpt(s):

Chapter 3: The Mother of the Mother of Tobacco Is a Snake
I left with the strange feeling that the problem had more to do with my incapacity to understand what people said, rather than the inadequacy of their explanations. they always used such simple words.
I was sitting in the main reading room, surrounded by students, and browsing over Claude Levi-Strauss's latest book, when I jumped. I had just read the following passage: "In Aztec, the word coatl means both 'serpent' and 'twin.' The name Quetzalcoatl can thus be interpreted either as 'Plumed serpent" or "Magnificent twin.'" A twin serpent, of cosmic origin, symbolizing the sacred energy of life? Among the Aztecs?
It was the middle of the afternoon. I needed to do some thinking. I left the library and started driving home. On the road back, I could not stop thinking about what I had just read. Staring out of the window, I wondered what all these twin beings in the creation myths of indigenous people could possibly mean.
When I arrived home, I went for a walk in the woods to clarify my thoughts. I started recapitulating from the beginning: I was trying to keep one eye on DNA and the other on shamanism to discover the common ground between the two. I reviewed the correspondences that I had found so far. Then I walked in silence, because I was struck. Ruminating over this mental block I recalled Carlos Perez Shuma's words: "Look at the FORM."
That morning, at the library, I had looked up DNA in several encyclopedias and had noted in passing that the shape of the double helix was most often described as a ladder, or a twisted rope ladder, or a spiral staircase. I was during the following split second, asking myself whether there were any ladders in shamanism, that the revelation occurred: "THE LADDERS! The shamans' ladders, 'symbols of the profession' according to Metraux, present in shamanic themes around the world according to Eliade!"
I rushed back to my office and plunged into Mircea Eliade's book Shamanism: Archaic techniques of ecstasy and discovered that there were "countless examples' of shamanic ladders on all five continents, here a "spiral ladder," there a "stairway" or "braided ropes." In Australia, Tibet, Ancient Egypt, Africa, North and South America, "the symbolism of the rope, like that of the ladder, necessarily implies communication between sky and earth. It is by means of a rope or a ladder (as, too, by a vine, a bridge, a chain of arrows, etc.) that the gods descended to earth and men go up to the sky." Eliade even cites an example from the Old Testament, where Jacob dreams of a ladder reaching up to heaven, "with the angels of God ascending and descending on it." According to Eliade, the shamanic ladder is the earliest version of the idea of an axis of the world, which connects the different levels of the cosmos, and is found in numerous creation myths in the form of a tree. (pages 62 - 63)
I was staggered. It seemed that no one had noticed the possible links between the "myths" of "primitive peoples" and molecular biology. No one had seen that the double helix had symbolized the life principle for thousands of years around the world. On the contrary, everything was upside down. It was said that the hallucinations could in no way constitute a source of knowledge, that Indians had found their useful molecules by chance experimentation, and that their "myths" were precisely myths, bearing no relationship to the real knowledge discovered in laboratories. (page 71)