In a study, researchers administered a drug to mice that blocked the reuptake of serotonin at the synaptic cleft. They then compared the mice with a control group that received saline. Behavioral observations indicated that the drug-treated mice showed reduced anxiety-related behaviors in an open-field test, while the saline group showed typical anxiety responses. Synaptic recordings confirmed elevated serotonin levels in the cleft for the experimental group.
The drug used in this study most directly functions as which type of agent?
- Acheck_circle
An agonist that increases serotonin's effect at the receptor
- B
An antagonist that blocks serotonin receptors
- C
A precursor that stimulates serotonin synthesis
- D
An enzyme that degrades excess serotonin
Explanation
Reuptake inhibitors prolong the action of a neurotransmitter in the synaptic cleft, thereby increasing its postsynaptic effect. Functionally, this acts as an agonist of serotonin signaling.