Molecular and pharmacodynamic interactions between caffeine and dopaminergic system

Many drugs targeting dopaminergic system were developed for treating schizophrenia (antagonists of D2 dopaminergic receptors, e.g. antipsychotics) or Parkinson' disease (agonists of dopaminergic receptors, e.g. L-DOPA). Because many of the patients treated with these drugs consume caffeine based beverages, pharmacodynamics and pharmacokinetics interactions between caffeine and dopaminergic system or drugs influencing this system are possible. The present review is assessing the current available scientific data on pharmacodynamics interactions between the dopaminergic and adenosinergic system but also on caffeine and dopaminergic system interactions. Caffeine can significantly improve Parkinson's disease symptoms but also the extrapyramidal syndrome induced by antipsychotics via dopaminergic pathways. No study so far has directly evaluated the influence of caffeine in schizophrenia, but there is growing evidence that adenosine dysfunction may contribute to the neurobiological and clinical features of schizophrenia. Caffeine has also effects on the reward system but it seems that this effect does not involve dopaminergic system. Caffeine has some endocrine effects via dopaminergic system such as decreasing the milk production in lactating women or other potential reproductive and nutritional consequences.