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.
An antagonist is a drug that blocks the response produced by an agonist. It interacts with the receptor or other component of the effector mechanism, but is devoid of intrinsic activity (ie, the ability to elicit a response upon binding to a receptor).t considers both drug action, which refers to the initial consequence of a drug-receptor interaction, and drug effect, which refers to the subsequent effects. The drug action of digoxin, for example, is inhibition of membrane Na + /K + -ATPase; the drug effect is augmentation of cardiac contractility.