The cause of fibromyalgia is unknown; however, it is believed to involve a combination of genetic and environmental factors with half the risk attributed to each. The condition runs in families and many genes are believed to be involved.
Agonist: A substance that acts like another substance and therefore stimulates an action. Agonist is the opposite of antagonist. Antagonists and agonists are key players in the chemistry of the human body and in pharmacology.
FULL AGONISTS. Full agonists are opioid drugs that bind to mu opioid receptors in the brain, and cause them to produce endorphins which give analgesic (pain relief) and, depending on the dose and frequency, addictive effects and feelings of euphoria.