A 43-yeаr-оld mаle with а histоry оf severe Treatment-Resistant Depression (TRD) and chronic generalized anxiety is being evaluated for a new psychopharmacological regimen. In analyzing the molecular profiles and downstream cascades of various neuroregulators to optimize his treatment, the psychiatric mental health nurse practitioner evaluates how different medications manipulate specific neurotransmitter systems. Which of the following statements accurately describe the neurobiology, receptor kinetics, or downstream cellular mechanisms of the targeted neurotransmitter systems? (Select All That Apply)