What do we call a chemical that mimics a neurotransmitter and can bind to receptor sites and cause postsynaptic potentials

A)  an agonist
B)  an artificial neurotransmitter 
C)  an endogenous neurotransmitter
D)  an antagonist

Agonist

A chemical or drug that binds to receptors in the brain and causes a reaction typically producing a biological response.

Antagonist

A substance that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it.

Artificial Neurotransmitter

A synthetically produced chemical used to emulate the effects of natural neurotransmitters in the nervous system.