Antidepressant drugs dopamine function

Bupropion is an atypical antidepressant drug that is the only nonnicotine-based prescription medicine approved for smoking cessation by the FDA. Its mechanism of action is presumed to be mediated by its capacity to block neuronal reuptake of dopamine and/or norepinephrine (Fiore et al. 2000). Relative to other antidepressants, bupropion has a relatively high affinity for the dopamine transporter (Baldessarini 2001). There is also evidence that bupropion acts as a functional nicotine antagonist, suggesting another potential mechanism by which bupropion could reduce smoking rates (Slemmer et al. 2000). 

In a manner similar to that observed following treatment with antidepressant drugs, the side effects of dopamine receptor blockade occur rather quickly but the clinical benefits require 2 to 3 weeks, or more, to fully develop. This also implies that compensatory changes in brain function are required for these drugs to produce clinical benefits in psychotic patients. These changes most likely require the activation or inactivation of... 

Prolactin-producing hypophyseal adenoma (prolactinoma) is the most common functional pituitary adenoma. Its prevalence peaks in women between 20 and 30 years of age. Hyperprolactinemia can be a cause of infertility and is associated with diminished gonadotropin secretion, secondary amenorrhea, and galactorrhea. The patient should first be examined for drug-induced hyperprolactinemia before any infertility work-up is initiated. For example, antidepressants, cimetidine, dopamine antagonists, reser-pine, sulpiride, verapamil, methyldopa, and estrogen therapy are known to interface with prolactin secretion. 

Monoamine oxidase inhibitors MAO is found in neural and other tissues, such as the gut and liver. In the neuron, this enzyme functions as a "safety valve" to oxidatively deaminate and inacti vate any excess neurotransmitter molecules (norepinephrine, dopamine, or serotonin) that may leak out of synaptic vesicles when the neuron is at rest. The MAO inhibitors2 may irreversibly or reversibly inactivate the enzyme, permitting neurotransmitter molecules to escape degradation and, therefore, to both accumu late within the presynaptic neuron and to leak into the synaptic space. This causes activation of norepinephrine and serotonin receptors, and may be responsible for the antidepressant action of these drugs. 

Amfebutamone is an amphetamine-like drug. It is structurally and pharmacologically distinct from other antidepressants, and apparently enhances both dopamine and noradrenaline function in the brain (SEDA-8, 18) (SEDA-10, 20). 

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