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.
Naloxone, buprenorphine and other opioid antagonists prevent the agonists from binding with the body's opioid receptors. Exercise promotes the release of endorphins, which serve as the body's natural pain relievers. Morphine sulfate is a powerful narcotic that mimics the action of endorphins, the body's natural opiates.