Time-course of changes in key catecholaminergic receptors and trophic systems in rat brain after antidepressant administration
Time is needed to observe the effects of antidepressants. A large study by Chiodo and Antelman, using an electrophysiological approach, showed a hypersensitivity of dopamine D2 autoreceptors 7-10 days after a single dose of imipramine or after electroshock, with an effect identical to that observed after chronic administration of pharmacological or non-pharmacological stimuli (Chiodo and Antelman, 1980). Based on large behavioural and biochemical data, a theory of 'time-dependent sensitisation' was proposed. Antelman postulated that dosage represents a foreign stress stimulus and, like activation of the immune system, can induce changes that are not immediate but can be long-lasting. According to Antelman, tissues exposed to a drug for the first time recognise its foreign nature and activate rapid non-specific adaptive processes, such as amphetamine-induced corticosterone release, which can also be observed two weeks after a single amphetamine dose (Antelman et al., 1992). How