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.
Endorphins are neurotransmitters, chemicals that pass along signals from one neuron to the next. Neurotransmitters play a key role in the function of the central nervous system and can either prompt or suppress the further signaling of nearby neurons. Endorphins are produced as a response to certain stimuli, especially stress, fear or pain. They originate in various parts of your body -- the pituitary gland, your spinal cord and throughout other parts of your brain and nervous system -- and interact mainly with receptors in cells found in regions of the brain responsible for blocking pain and controlling emotion.