Role of the dopaminergic system in depression
ABSTRACT A hypothesis implicating dopamine in depression was proposed over 15 years ago (Randrup et al 1975). The identification of multiple new subtypes of dopamine receptors and evolving views regarding the function of the dopamine systems in the brain require a reexamination of this hypothesis. Results from studies in depression, Parkinson's disease, and animal models of depression suggest a deficiency of dopamine in depression. Dopamine precursors, dopamine agonists, and dopamine reuptake inhibitors show therapeutic efficacy in depression. Electroconvulsive therapy (ECT) and standard pharmacological antidepressants enhance dopamine function. Studies using receptor-specific drugs in clinical trials and neuroimaging studies are needed to further clarify the role of dopamine in depression.
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ABSTRACT: A substantial proportion of depressed patients do not respond to current antidepressant drug therapies. So far, antidepressant drugs have been developed based on the "monoaminergic hypothesis" of depression, which considers a synaptic deficiency in 5-hydroxytryptamine (5-HT; serotonin) or noradrenaline as main cause. More recently, the dopaminergic system has been implicated in the efficacy of some antidepressants, such as desipramine, amineptine, nomifensine. Dysfunction of dopaminergic neurotransmission within the mesolimbic system may contribute to anhedonia, loss of motivation and psychomotor retardation in severe depressive disorders. Dopamine D3 receptor subtype is located both pre- and postsynaptically in brain areas regulating motivation and reward-related behavior and has been implicated in depression-like behaviors. Activity of mesolimbic dopamine neurons in the reward circuit is a key determinant of behavioral susceptibility/resilience to chronic stress, which plays a central role in the pathogenesis of depression. Dopamine D3 receptor expression and function are both down-regulated in stress and depression, and these changes are reversed by antidepressant treatments, suggesting that enhanced dopaminergic neurotransmission mediated by dopamine D3 receptor participates in adaptive changes related to antidepressant activity. Of note, brain derived neurotrophic factor (BDNF) controls the expression of the dopamine D3 receptor in some brain areas and BDNF induction by antidepressant treatments is related to their behavioral activity. A number of experimental drugs in pre-clinical or clinical development, including aripiprazole and cariprazine, may act as antidepressants because of their partial agonist activity at dopamine D3 receptors. These preclinical and clinical data are discussed in the present review.European journal of pharmacology 07/2013; 719(1-3). DOI:10.1016/j.ejphar.2013.07.022
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ABSTRACT: Zuojin Pill (ZJP), a traditional Chinese medicinal decoction, contains two herbal drugs: Coptis chinensis Franch. and Evodia rutaecarpa (Juss.) Benth. in the ratio of 6:1 (w/w). Previous pharmacological studies have shown that two herbs in ZJP have the antagonistic effects on catecholamine secretion in bovine adrenal medullary cells. Furthermore, the alkaloids from the two herbs in ZJP may provide a protective effect for depression in individuals with a low expressing 5-HTT allele by increasing receptor concentration in serotonergic neurons. However, antidepressant effect has not been reported before and has not been fully clarified.Journal of ethnopharmacology 05/2013; 148(2). DOI:10.1016/j.jep.2013.05.011
- Clinical, Research and Treatment Approaches to Affective Disorders, 02/2012; , ISBN: 978-953-51-0177-2