Psychiatric Drugs and Medications Q 39

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Antidepressants generally exert influence by:

  

     A. Increasing the reuptake of norepinephrine

     B. Altering the action of the cyproprotein (MAO)

     C. Changing the availability of dopamine

     D. Changing the availability of select neurotransmitters

    

    

Correct Answer: D. Changing the availability of select neurotransmitters

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This choice best describes the effect of antidepressants in general. All currently licensed antidepressants are believed to work by increasing the neurotransmitters serotonin or norepinephrine, or both, in the synapse. The mechanisms to increase these neurotransmitters vary, though antidepressant drugs target reuptake by the nerve terminals.

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Option A: Selective serotonin reuptake inhibitors (SSRIs) work by inhibiting 5-HT reuptake by the presynaptic cleft in a synapse, thus increasing available serotonin levels. Serotonin and norepinephrine reuptake inhibitors (SNRIs) block serotonin reuptake, like SSRIs, however, they also block norepinephrine reuptake in the synapse.

Option B: Monoamine oxidase inhibitors (MAOIs), work by inhibiting the monoamine oxidase enzyme, which catabolizes serotonin, norepinephrine, and dopamine. Another antidepressant drug that does not work by blocking reuptake is mirtazapine. Mirtazapine works by blocking alpha-2 adrenergic receptors on the cell bodies and nerve terminals, promoting the release of norepinephrine into the synapse.

Option C: Another atypical antidepressant, agomelatine, works by agonizing melatonin receptors MT1 and MT2 while antagonizing serotonergic 5-HT2C receptors, promoting dopamine and norepinephrine release. Serotonin modulators, like nefazodone, may work by down-regulating postsynaptic serotonin 5-HT2A receptors.

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