[Dopamine receptor subtypes].

Dopamine is a neurotransmitter in both central and peripheral nervous system. In the central nervous system dopamine is involved in regulation of: movements, emotional processing of sensory input, appetite, vomiting and secretion of anterior pituitary hormones. The most important peripheral effect of dopamine is control of splanchnic and renal blood flows. There are five subtypes of dopamine receptors. D1 receptors are responsible for majority of peripheral dopamine effects; in the brain they modulate activity of limbic system. Symptoms of schizophrenia are produced by increased activation of D2 and D4 receptors. On the other hand, Parkinson's syndrome could be induced by D2 receptors blockade. D3 receptors decrease craving in drug-dependent laboratory animals. Although D5 receptors were found in many brain regions and in peripheral blood lymphocytes, their functions remain unknown. Linking dopamine receptor subtypes with actual effects of dopamine will enable more selective therapy of disorders caused by malfunction of this important system.