Cold sore: Viruses or localised infections can cause the eye to redden â the problem usually starts in one eye, but can spread to both. The cold sore virus, which 90 per cent of us carry, can sometimes also infect the eye, causing inflammation.
Endorphins are chemicals, called peptides, that are made in the body. They have much of the same effect on a person as opium or morphine. As a result, they actually lower the feeling of pain in the body and can create a feeling of bliss or euphoria.
With further research, the two groups of scientists found not one but a whole family of these endogenous pain-killing chemicals. The Aberdeen investigators called the smaller members of the family enkephalins, which translates into in the head (Cook, 1998). In time the larger molecules were also discovered and it was called endorphins, meaning the morphine within. Nowadays, the word endorphins is often used to refer to the groups as a whole.