Final answer:
An agonist mimics a neurotransmitter's effects, while an antagonist inhibits its release and blocks its effect.
Step-by-step explanation:
An agonist is a drug that mimics the effects of a neurotransmitter by binding to its receptors. It activates the receptors and produces a similar response as the neurotransmitter. On the other hand, an antagonist blocks the effects of a neurotransmitter by binding to its receptors without activating them. It inhibits the release and blocks the function of the neurotransmitter.
For example, dopamine agonists are used to treat Parkinson's disease, while selective serotonin reuptake inhibitors (SSRIs) act as serotonin agonists to treat depression. These drugs help restore the balance of neurotransmitters in the brain.
In summary, an agonist mimics a neurotransmitter's effects, while an antagonist inhibits its release and blocks its effect.
Learn more about neurotransmitters