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.
A drug that is an agonist attaches itself to receptors in the brain, and then produces a chemical reaction. For example, heroin is an opioid agonist. It binds to opioid receptors that control pleasure and pain, the result being a feeling of euphoria and well being.Other examples of opioid agonists, sometimes referred to as âfull agonists,â are oxycodone, morphine and opium.or example, heroin is an opioid agonist. It binds to opioid receptors that control pleasure and pain, the result being a feeling of euphoria and well being. Other examples of opioid agonists, sometimes referred to as âfull agonists,â are oxycodone, morphine and opium.