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). However, later exposure to the drug may result in a stronger response, as observed during immune responses and after administration of antipsychotics (Antelman et al., 2000). Biochemical data obtained in our study indicate the dynamic reaction of the CNS to drugs administered acutely, which may be a strong evidence that short and transient blockade of neurotransmitter reuptake affects the further function of neuronal networks. 

Our biochemical study on the delayed effects of antidepressants has been published! 

We encourage you to read !

Time-course of changes in key catecholaminergic receptors and trophic systems in rat brain after antidepressant administration - PubMed (nih.gov)