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.