The importance of brain serotonergic receptor mechanisms for the action of antidepressant drugs.

The present studies have shown that chronic antidepressant treatment with different types of antidepressant drugs results in adaptive changes in postsynaptic 5-HT receptor mechanisms which appear to result in 5-HT sub- or supersensitivity development depending upon the 5-HT nerve terminal system analyzed. The results underline the heterogeneity of the central 5-HT neuron systems in their responses to chronic antidepressant treatment. In addition, a number of antidepressant drugs have potent, direct actions on 5-HT2 receptors, which may be of clinical relevance.