Endorphins Definition

Endorphins ("endogenous morphine") are part of a group of chemicals that naturally exist in the brain and help to alleviate pain and elevate a person's mood and spirit – very much like Opioids, thus being what we call endogenous opioidpeptides. They are neurotransmitters usually defined as neuromodulators – chemicals that change the activity of the postsynaptic cells and/or regulate it.
These chemicals are produced by the pituitary gland and the hypothalamus during physical activity, sexual activity, joy, pain, laughter massage and even during sleep. It is also well established that eating chocolate causes release of endorphins.
The Endorphins play an important role in controlling the emotional behaviors (such as anxiety, fear and pleasure) and pain.
Drugs such as opium and morphine attach to the same receptors as the Endorphins, which can hint us as to the role of these neuro-modulators. Some people call Endorphins the "Keys to Heaven" because of their ability enable control over pleasure and pain.

The term endorphin implies a pharmacological activity (analogous to the activity of the corticosteroid category of biochemicals) as opposed to a specific chemical formulation. It consists of two parts: endo- and-orphin; these are short forms of the words endogenous and morphine, intended to mean "a morphine-like substance originating from within the body".
The term "endorphin rush" has been adopted in popular speech to refer to feelings of exhilaration brought on by pain, danger, or other forms of stress, supposedly due to the influence of endorphins. When a nerve impulse reaches the spinal cord, endorphins that prevent nerve cells from releasing more pain signals are released. Immediately after injury, endorphins allow animals to feel a sense of power and control over themselves that allows them to persist with activity for an extended time.