Previous studies using a variety of drugs with different affinities for the dopamine (DA) D3 receptor suggested that this receptor is involved in regulating motor activity and hypothermia. However, the in vivo selectivity of many of these compounds has been repeatedly questioned. To examine the precise roles of the DA D3 receptor in motor activity and hypothermic responses, we used mutant mice ...

Dopamine plays an important role in the regulation of renal sodium excretion. The synthesis of dopamine and the presence of dopamine receptor subtypes (D1A, D1B, as D1-like and D2, and D3 as D2-like) have been shown within the kidney. The activation of D1-like receptors located on the proximal tubules causes inhibition of tubular sodium reabsorption by inhibiting Na,H-exchanger and Na,K-ATPase ...

Background Cariprazine, a D3-preferring dopamine D2/D3 receptor partial agonist, is a new antipsychotic drug recently approved in the United States for the treatment of schizophrenia and bipolar mania. We recently demonstrated that cariprazine also has significant antianhedonic-like effects in rats subjected to chronic stress; however, the exact mechanism of action for cariprazine's antidepress...

The cloning of the D2 dopamine receptor (6) in 1988 and the subsequent identification of multiple dopamine receptors referred to as D1, D3, D4, and D5 (10, 35, 46, 48, 49, 52, 54, 59) has profoundly changed our understanding of dopamine receptor anatomy and pharmacology. Prior to the isolation of these dopamine receptor subtypes, the dopamine field distinguished two subtypes of dopamine recepto...

The cDNA for the dopamine D3 receptor was isolated and characterized in 1990. Subsequent studies have indicated that D3 receptors, as well as D3 receptor mRNA, are primarily localized in limbic regions in mammals. This finding led to the postulate that D3 receptors may be involved in drug dependence and addiction. However, this hypothesis has been difficult to test due to the lack of compounds ...

The neuromodulator dopamine plays an important role in synaptic plasticity. The effects depend on receptor subtypes, affinity, concentration level, and the kind of neuroplasticity induced. In animal experiments, dopamine D2-like receptor stimulation revealed partially antagonistic effects on plasticity, which might be explained by dosage dependency. In humans, D2 receptor block abolishes plasti...

Repeated exposure to cocaine can induce persistent alterations in the brain. The structural remodeling of dendrites and dendritic spines is thought to play a critical role in cocaine addiction. We previously demonstrated that signaling via dopamine D1 and D3 receptors have opposite effects on cocaine-induced gene expression. Here, we show that cocaine-induced structural remodeling in the nucleu...

D3 receptors act synergistically with D1 receptors to inhibit sodium transport in renal proximal tubules; however, the mechanism by which this occurs is not known. Because dopamine receptor subtypes can regulate and interact with each other, we studied the interaction of D3 and D1 receptors in rat renal proximal tubule (RPT) cells. The D3 agonist PD128907 increased the immunoreactive expression...

Anti-psychotic drugs The anti-psychotic drugs, e.g. haloperidol and chlorpromazine, comprise a large group of drugs that are used to treat the symptoms of schizophrenia [ l ] . The principal therapeutic effect of the drugs is on the positive (psychotic) symptoms of the disorder, although some drugs, e.g. clozapine, are claimed to have effects on the negative symptoms. After the discovery of dop...

PROGRESS TOWARDS DEVELOPMENT OF MULTIFUNCTIONAL, DOPAMINED2/D3 RECEPTOR AGONISTS AS SYMPTOMATIC AND DISEASE-MODIFYINGTHERAPEUTIC AGENTS FOR PARKINSON’S DISEASE