Final answer:
An agonist explains the paradoxical effect of stimulants in calming down children with ADHD, as these medications increase dopamine levels in the brain, leading to improved attention and reduced hyperactivity.
Step-by-step explanation:
The paradoxical effects of giving children with attention deficit hyperactivity disorder (ADHD) a stimulant to calm them down can be explained by the action of an agonist. Stimulant medications used for ADHD treatment increase neurotransmitter activity in the brain areas associated with impulse control, such as the prefrontal cortex and basal ganglia, thereby improving attention and reducing hyperactivity.
These stimulants, including amphetamines, block the reuptake of dopamine as well as stimulate its release, which increases dopamine levels in certain parts of the brain, ultimately leading to a calming effect. This is contrary to what one might expect from a stimulant, which is why the effect is described as paradoxical. On the other hand, an antagonist decreases the activity of neurotransmitters, which is not the effect stimulant medications for ADHD are designed to produce.