RECENT PHARMACOLOGICAL ADVANCES IN ANTIDEPRESSANT THERAPY

The serotonergic properties of newer generation antidepressants unders core the role of 5-hydroxytryptamine (5-HT, serotonin) in both the pat hophysiology and the pharmacotherapy of major depression. Clinical dif ferences between selective serotonin reuptake inhibitors (SSRIs) and t ricyclic antidepressants (TCAs) are attributed to the greater potency and selectivity for 5-HT transporter inhibition by the SSRIs and the c omparatively weak interaction of the SSRIs with nonserotonin neurotran smitter receptors. The SSRIs, monoamine oxidase inhibitors (MAOIs), an d TCAs share a common adaptive regulation of noradrenergic, 5-HT, and glutamate neurotransmission, suggesting possible unifying mechanisms o f action underlying their antidepressant effects, In vivo neuroimaging techniques, such as positron emission tomography (PET) and single pho ton emission computed tomography (SPECT) have yielded a functional neu roanatomy of compromised neurocircuitry in major depression and promis e to be invaluable in mapping the in vivo effects of future novel anti depressant drugs.