5-HT-1A receptor-mediated effects of antidepressants.

1. Antidepressant (AD) drugs in general induce subsensitivity of behavioural functions associated with activation of 5-HT-1a receptors in animals. 2. Electrophysiological studies in animals in general indicate increased serotonergic transmission after AD administration, mediated partly by increased functioning of post-synaptic 5-HT-1a receptors in the hippocampus. 3. Binding studies have in general shown no change in 5-HT-1a receptor number either pre-or post-synaptically, while results of second messenger studies (inhibition of adenylate cyclase) indicate subsensitivity after AD administration. 4. Human studies also indicate subsensitivity of 5-HT-1a receptors after ADs.