(biology) Any chemical or agent which regulates one or more genes by increasing the rate of transcription.
One who, or that which, activates.
An opponent or enemy.
One who antagonizes or stirs.
(biochemistry) A chemical that binds to a receptor but does not produce a physiological response, blocking the action of agonist chemicals.
2001: The calcium antagonists represent one of the top ten classes of prescription drugs in terms of commercial value, with worldwide sales of nearly $10 billion in 1999. " Leslie Iversen, Drugs: A Very Short Introduction (Oxford 2001, p. 41)