Agonist The term “agonist” was given to heros within Greek dramas and stands as a personification for their biological function, as an agonist is a drug which enhances a neurotransmitter’s activity. Agonists may work in one of a few ways. First, an agonist may block reuptake, a process which sends transmitters back to their appropriate presynaptic neuron. If the transmitter fails to complete reuptake, it remains within the synapse and therefore continues to be influential. Secondly, agonists might counter-balance reuptake by increasing precursor, a substance which allows for the neurotransmitter’s creation. In this way, though neurotransmitters are being sent back to their appropriate presynaptic neuron, more of the same neurotransmitters are being created, thus there is less of a net loss of that specified neurotransmitter.
Antagonist Accordingly, an “antagonist”, which is the term given for whoever opposes the hero, is a drug which impedes neurotransmitter activity. An antagonist may work by increasing the rate by which reuptake occurs, by increasing the strength of enzyme responsible for coordinating reuptake, or by limiting the amount of precursors available. For example, South American Indians have been covering their arrows in the antagonist curare, a substance found in a plant extract. This antagonist works by impeding acetylcholine at the synapse juncture between motoneurons and muscle fibers, resulting in total paralysis and eventual death from suffocation.
Agonist and Antagonist Grey Area However, agonists are not always more beneficial than antagonists. Though it is true the antagonist curare is lethal, the venom found in a black widow spider is an agonist which is as dangerous as curare. This particular agonist increases acetylcholine production at the neuromuscular juncture. However, this quickly exhausts the neuron’s quantity of neurotransmitter because it cannot produce enough to counter-balance the expedited rate by which it is used. Thus, someone suffering from a curare injection or that of the venom from a black widow will ultimately face the same paralyzed state, though the first was instigated by an antagonist and the second from an agonist.
Gerow, Joshua R., Roddrick Chatmon, and Don Crews. Basic Psychology. New York: Custom Pub., 2009. Print.