Both splicing variants of the dopamine D2 receptor mRNA are up-regulated by antipsychotic drugs

Structural Basis and Mechanism of Chiral Benzedrine Molecules Interacting With Third Dopamine Receptor

In order to investigate the chiral benzedrine molecules corresponding to their different characteristics in biochemical systems, we studied their interaction with D3 R using the docking method, molecular dynamic simulation, and quantum chemistry. The obtained results indicate that the active residues for R-benzedrine (RAT) bound with D3 R are Ala132, Asp133, and Tyr55, while Asn57, Asp133, Asp168, Cys172, Gly54, Trp24, and Vall136 act as the active residues for S-benzedrine (SAT). The different active pockets are observed for ART or SAT because they possess different active residues. The binding energies between RAT and SAT with D3 R were determined to be -44.0 kJ.mol(-1) and -71.2 kJ.mol(-1) , respectively. These results demonstrate that SAT within the studied pocket of D3 R has a stronger capability of binding with D3 R, while it is more feasible for RAT to leave from the interior positions of D3 R. In addition, the results suggest that the D3 R protein can recognize chiral benzedrine molecules and influence their different addictive and pharmacological effects in biochemical systems. Chirality 28:674-685, 2016. © 2016 Wiley Periodicals, Inc.

Psychotropic drug effects on gene transcriptomics relevant to Parkinson's disease

OBJECTIVES

Psychotropic drugs are widely prescribed in Parkinson's disease (PD) without regard to their pathobiological effects, and these drugs affect the transcription of a large number of genes. Effects of these drugs on PD risk gene transcription were therefore surveyed.

METHODS

Results summarize a comprehensive survey of psychotropic effects on messenger ribonucleic acid (mRNA) expression evident in published data for 70 genes linked to PD risk.

RESULTS

Psychotropic drugs can meaningfully affect PD risk gene mRNA transcription, including antipsychotics (upregulate dopamine receptors D2 and D3 (DRD2, DRD3); downregulate low-density lipoprotein receptor-related protein 8 (LRP8), ubiquitin carboxyl-terminal esterase L1 (UCHL1, also known as PARK5)), haloperidol (upregulates DRD3, parkin (PRKN, also known as PARK2), DRD2; downregulates brain-derived neurotrophic factor (BDNF)), risperidone (upregulates monoamine oxidase B (MAOB), DRD2), olanzapine (upregulates transmembrane protein 163 (TMEM163), BDNF, glutathione S-transferase mu 1 (GSTM1), MAOB, DRD2, solute carrier organic anion transporter family, member 3A1 (SLCO3A1)), aripiprazole (upregulates DRD2), quetiapine, paliperidone, lurasidone, carbamazepine, and many antidepressants (upregulate BDNF), lithium and bupropion (downregulate BDNF), amitriptyline (upregulates DRD3, DRD2), imipramine (upregulates BDNF, DRD3, DRD2), desipramine (upregulates BDNF, DRD3), and fluoxetine (upregulates acid beta-glucosidase (GBA), coiled-coil domain containing 62 (CCDC62), BDNF, DRD3, UCHL1, unc-13 homolog B (UNC13B), and perhaps huntingtin interacting protein 1 related (HIP1R); downregulates microtubule-associated protein tau (MAPT), methylcrotonoyl-coenzyme A carboxylase I (MCCC1), GSTM1, 28kDa calbindin 1 (CALB1)). Fluoxetine effects on BDNF and UCHL1 in GEO Profiles were statistically robust.

CONCLUSIONS

This report provides an initial summary and framework to understand the potential impact of psychotropic drugs on PD-relevant genes. Antipsychotics and serotoninergic antidepressants may potentially attenuate PD risk, and lithium and bupropion may augment risk, through MAPT, GBA, CCDC62, HIP1R, BDNF, and DRD2 transcription, with MAPT, GBA, and CCDC62 being strongly associated with PD risk in recent meta-analyses. Limitations of these findings and a research agenda to better relate them to the nigrostriatum and PD are discussed.

The neuroprotective disease-modifying potential of psychotropics in Parkinson's disease

Neuroprotective treatments in Parkinson's disease (PD) have remained elusive. Psychotropics are commonly prescribed in PD without regard to their pathobiological effects. The authors investigated the effects of psychotropics on pathobiological proteins, proteasomal activity, mitochondrial functions, apoptosis, neuroinflammation, trophic factors, stem cells, and neurogenesis. Only findings replicated in at least 2 studies were considered for these actions. Additionally, PD-related gene transcription, animal model, and human neuroprotective clinical trial data were reviewed. Results indicate that, from a PD pathobiology perspective, the safest drugs (i.e., drugs least likely to promote cellular neurodegenerative mechanisms balanced against their likelihood of promoting neuroprotective mechanisms) include pramipexole, valproate, lithium, desipramine, escitalopram, and dextromethorphan. Fluoxetine favorably affects transcription of multiple genes (e.g., MAPT, GBA, CCDC62, HIP1R), although it and desipramine reduced MPTP mouse survival. Haloperidol is best avoided. The most promising neuroprotective investigative priorities will involve disease-modifying trials of the safest agents alone or in combination to capture salutary effects on H3 histone deacetylase, gene transcription, glycogen synthase kinase-3, α-synuclein, reactive oxygen species (ROS), reactive nitrogen species (RNS), apoptosis, inflammation, and trophic factors including GDNF and BDNF.

The role of dopamine in reward and pleasure behaviour--review of data from preclinical research

OBJECTIVE

The purpose of this article is to review some of the basic aspects of the dopaminergic system and its role in reward and pleasure behaviour. We also discuss the association between dopamine and unpleasant symptoms that are commonly found in neuropsychiatric disorders and may also be side-effects of neuroleptic drugs.

METHOD

A computer-based search of the literature, augmented by extensive bibliography-guided article reviews, were used to find basic information on the dopamine and the reward systems, and symptoms such as dysphoria, anhedonia and depression.

RESULTS

Central dopaminergic neurotransmission is complex, having multiple actions at each level of the mesocorticolimbic reward pathway. The role of dopamine in the reward process was classically associated with the ability to experience pleasure; recent data suggest a more motivational role. Dysfunction of the dopamine transmission in the reward circuit is associated with symptoms such as anhedonia, apathy and dysphoria found in several neuropsychiatric disorders, including Parkinson's disease, depression, drug addiction, and neuroleptic-induced dysphoria.

CONCLUSION

Viewing the dysfunctions of the reward pathways within a broader spectrum and exploring its complex relations with the dopaminergic transmission may help understand the pathophysiology of these neuropsychiatric disorders and lead to a rational development of novel treatments.

Reversal of antipsychotic-induced working memory deficits by short-term dopamine D1 receptor stimulation

Chronic blockade of dopamine D2 receptors, a common mechanism of action for antipsychotic drugs, down-regulates D1 receptors in the prefrontal cortex and, as shown here, produces severe impairments in working memory. These deficits were reversed in monkeys by short-term coadministration of a D1 agonist, ABT 431, and this improvement was sustained for more than a year after cessation of D1 treatment. These findings indicate that pharmacological modulation of the D1 signaling pathway can produce long-lasting changes in functional circuits underlying working memory. Resetting this pathway by brief exposure to the agonist may provide a valuable strategy for therapeutic intervention in schizophrenia and other dopamine dysfunctional states.

Aripiprazole, a novel antipsychotic drug, inhibits quinpirole-evoked GTPase activity but does not up-regulate dopamine D2 receptor following repeated treatment in the rat striatum

Aripiprazole, a quinolinone derivative, is a new dopaminergic agent which has been recently developed and demonstrated to be clinically useful as an antipsychotic drug with reduced extrapyramidal motor side effects. Here, we found that aripiprazole competed [3H]spiperone binding with a 100-fold higher affinity than [3H]SCH23390 binding, and inhibited the quinpirole-induced facilitation of high-affinity GTPase activity in rat striatal membranes. The effects of chronic administration of aripiprazole and haloperidol on dopamine D2 receptor binding and mRNA level in rat striata were examined by a [3H]spiperone binding assay and a ribonuclease protection assay. Haloperidol induced a significant rise in Bmax of [3H]spiperone binding at 1 mg/kg and in the level of dopamine D2L receptor mRNA at 4 mg/kg. A high dose of aripiprazole (100 mg/kg) only tended to increase the Bmax of [3H]spiperone binding non-significantly, and had no effect on the level of dopamine D2L receptor mRNA. These results indicated that aripiprazole had an antagonistic activity to dopamine D2 receptors with a high affinity, but that the potency of aripiprazole to up-regulate dopamine D2 receptors in the striatum was much smaller than that of haloperidol. This small up-regulation may be related to the ability to aripiprazole to act without side effects including tardive dyskinesia.

Effect of S(-)- and R(+)-salsolinol on the POMC gene expression and ACTH release of an anterior pituitary cell line

Tetrahydroisoquinolines (TIQs) are thought to play an important role in the process of development of alcohol dependence. Being a condensation product between the alcohol metabolite acetaldehyde and dopamine they might be involved in the balance of the opioid system as well as the reward system. Therefore, the influence of the TIQ salsolinol (SAL) on the pro-opiomelanocortin (POMC) gene expression was investigated using the ArT-20 mouse anterior pituitary tumor cell line. Our results show a significant decrease in the POMC gene expression by the S(-)-enantiomer of SAL. The basal secretion of adrenocorticotropin (ACTH) as well as the corticotropin-releasing factor (CRF)-stimulated ACTH released remained unchanged after R(+)- and S(-)-SAL treatment. Interestingly, it was clearly shown that a reduction of intracellular cAMP level occurred after the treatment of the cells with S(-)-SAL whereas R(+)-SAL did not affect the cAMP production. The obtained results suggest that S(-)-SAL is possibly involved in the establishment of the opioid deficiency in alcoholics.

The effect of haloperidol on D2 dopamine receptor subtype mRNA levels in the brain

Chronic neuroleptic treatment induces an increase in the density of D2 dopamine receptors in the striatum. The effect of prolonged administration of haloperidol on mRNA levels of the short (D2S) and long (D2L) isoforms of the D2 dopamine receptor and the D3 dopamine receptor in different brain regions was examined. Haloperidol caused a significant rise in both D2L and D2S mRNA levels in the striatum, but had no effect on D3 mRNA levels. This rise was restricted to the striatum, showing that the effect of haloperidol on dopamine receptor mRNA is both subtype- and tissue-specific.

Clozapine and sulpiride up-regulate dopamine D3 receptor mRNA levels

Chronic treatment (32 days) with sulpiride (100 mg/kg/day) up-regulated rat brain dopamine D3 receptor mRNA levels by 4-fold but had no effect on the mRNA levels encoding the dopamine D1A, D1B or D2 receptors or the enzymes tyrosine hydroxylase and aromatic amino acid decarboxylase as measured by multiprobe oligonucleotide solution hybridisation. Clozapine (30 mg/kg/day) increased D3 receptor mRNA levels by 5-fold after 4 days, the level dropping to basal after 32 days and also increased D1B mRNA levels by 0.5-fold in a similar pattern. Clozapine did not affect any other dopamine receptors or the synthesising enzyme mRNA levels. We have previously shown that the typical antipsychotics haloperidol and loxapine also increased the mRNA levels of the dopamine D3 receptor and these results suggest that up-regulation of dopamine D3 receptor mRNA may be associated with the therapeutic action of antipsychotic drugs.