Dopamine signaling in the striatum

Ganshuang granule plays a pharmacological role in anti-alcoholic and anti-hangover via regulating alcohol metabolism and affecting neurotransmitters

BACKGROUND

To explore the effect of Ganshuang granule on anti-alcoholic and anti-hangover and its potential mechanism.

METHODS

SPF SD rats' drunken model and SPF Kunming mice's hangover model were used as models.

RESULTS

Ganshuang granule could significantly reduce sleep time, the time to climb in mice, and significantly prolong the tolerance time and shorten sleep time in rats (p < 0.05). The blood ethanol concentration of rats in each administration group was lower than that in the model group at each time point (p < 0.05). Compared with the control group, the activities of ADH and ALDH in the liver of the model group were significantly decreased (p < 0.05); the content of DA and 5-HT in the striatum of the model group was significantly increased (p < 0.05); and the activity of AchE in the hippocampus was significantly decreased (p < 0.05). The above processes could be improved and regulated in the drug administration group. Compared with the control group, there was no significant difference between ADH and ALDH in the serum of the model group (p > 0.05). However, the activities of ADH and ALDH in the liver of drunk rats could be upregulated by Ganshuang granule (p < 0.05).

CONCLUSION

Ganshuang granule has the pharmacological effects of anti-alcoholic and anti-hangover, which is related to regulating the activities of ADH and ALDH in the liver, the contents of DA and 5-HT in striatum, and the activity of AchE in the hippocampus.

Age-Dependent Modulation of Layer V Pyramidal Neuron Excitability in the Mouse Primary Motor Cortex by D1 Receptor Agonists and Antagonists

The primary motor cortex (M1) receives dopaminergic (DAergic) projections from the midbrain which play a key role in modulating motor and cognitive processes, such as motor skill learning. However, little is known at the level of individual neurons about how dopamine (DA) and its receptors modulate the intrinsic properties of the different neuronal subpopulations in M1 and if this modulation depends on age. Using immunohistochemistry, we first mapped the cells expressing the DA D1 receptor across the different layers in M1, and quantified the number of pyramidal neurons (PNs) expressing the D1 receptor in the different layers, in young and adult mice. This work reveals that the spatial distribution and the molecular profile of D1 receptor-expressing neurons (D1+) across M1 layers do not change with age. Then, combining whole-cell patch-clamp recordings and pharmacology, we explored ex vivo in young and adult mice the impact of activation or blockade of D1 receptors on D1+ PN intrinsic properties. While the bath application of the D1 receptor agonist induced an increase in the excitability of layer V PNs both in young and adult, we identified a distinct modulation of intrinsic electrical properties of layer V D1+ PNs by D1 receptor antagonist depending on the age of the animal.

ADHD co-morbidities: A review of implication of gene × environment effects with dopamine-related genes

ADHD is a major burden in adulthood, where co-morbid conditions such as depression, substance use disorder and obesity often dominate the clinical picture. ADHD has substantial shared heritability with other mental disorders, contributing to comorbidity. However, environmental risk factors exist but their interaction with genetic makeup, especially in relation to comorbid disorders, remains elusive. This review for the first time summarizes present knowledge on gene x environment (GxE) interactions regarding the dopamine system. Hitherto, mainly candidate (GxE) studies were performed, focusing on the genes DRD4, DAT1 and MAOA. Some evidence suggest that the variable number tandem repeats in DRD4 and MAOA may mediate GxE interactions in ADHD generally, and comorbid conditions specifically. Nevertheless, even for these genes, common variants are bound to suggest risk only in the context of gender and specific environments. For other polymorphisms, evidence is contradictory and less convincing. Particularly lacking are longitudinal studies testing the interaction of well-defined environmental with polygenic risk scores reflecting the dopamine system in its entirety.

Reveal the Antimigraine Mechanism of Chuanxiong Rhizoma and Cyperi Rhizoma Based on the Integrated Analysis of Metabolomics and Network Pharmacology

Migraine is a common neurological disorder that manifests as recurrent attacks of unilateral and throbbing headache. Conioselinum anthriscoides “Chuanxiong” (Apiaceae; Chuanxiong rhizoma) and Cyperus rotundus L. (Cyperaceae; Cyperi rhizoma) (CRCR), is a classic prescription for treating migraine. This study aimed to reveal the potential mechanisms of CRCR extract against migraine using integrated analysis of metabolomics and network pharmacology. Behavioral changes in the nitroglycerin rat migraine model were determined from von Frey withdrawal response. Untargeted serum metabolomics was used to identify the differentially expressed metabolites and metabolic pathways. The differentially expressed metabolites were analyzed to obtain the corresponding targets by a compound–reaction–enzyme–gene network. Network pharmacology was used to construct a compound–target–pathway network. The common targets of metabolomics and network pharmacology were further analyzed. Metabolomics analysis identified 96 differentially expressed metabolites and 77 corresponding targets. Network pharmacology analysis identified 201 potential targets for CRCR against migraine. By intersecting 77 targets with 201 targets, monoamine oxidase A (MAO-A), monoamine oxidase B (MAO-B), and catechol-O-methyltransferase (COMT) were identified as the common targets, and MAO-A, MAO-B, and COMT were involved in the tyrosine metabolism pathway. Further experiments demonstrated that the contents of MAO-A and COMT were significantly increased in serum and brainstem tissue of the migraine rats. CRCR extract significantly decreased the contents of MAO-A and COMT, while no significant difference was found in MAO-B. Metabolomics analysis indicated that the contents of 3,4-dihydroxyphenylacetate (DOPAC) and 3-(4-hydroxyphenyl)pyruvate (HPP) were significantly increased in the migraine rats, and CRCR extract caused significant decreases in DOPAC and HPP. Interestingly, DOPAC and HPP were two differentially expressed metabolites involved in the tyrosine metabolism pathway. Correlation analysis showed that DOPAC and HPP were highly positively correlated with MAO-A and COMT. Taken together, two key differentially expressed metabolites (DOPAC and HPP), two key targets (MAO-A and COMT), and one relevant metabolic pathway (tyrosine metabolism) showed great importance in the treatment of migraine. This research could provide a new understanding of the potential mechanism of CRCR against migraine. More attentions should be paid into the tyrosine metabolism pathway in future studies.

Immunomodulatory Effects of Dopamine in Inflammatory Diseases

Dopamine (DA) receptor, a significant G protein-coupled receptor, is classified into two families: D1-like (D1 and D5) and D2-like (D2, D3, and D4) receptor families, with further formation of homodimers, heteromers, and receptor mosaic. Increasing evidence suggests that the immune system can be affected by the nervous system and neurotransmitters, such as dopamine. Recently, the role of the DA receptor in inflammation has been widely studied, mainly focusing on NLRP3 inflammasome, NF-κB pathway, and immune cells. This article provides a brief review of the structures, functions, and signaling pathways of DA receptors and their relationships with inflammation. With detailed descriptions of their roles in Parkinson disease, inflammatory bowel disease, rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis, this article provides a theoretical basis for drug development targeting DA receptors in inflammatory diseases.

PDE10A Inhibitors-Clinical Failure or Window Into Antipsychotic Drug Action?

PDE10A, a phosphodiesterase that inactivates both cAMP and cGMP, is a unique signaling molecule in being highly and nearly exclusively expressed in striatal medium spiny neurons. These neurons dynamically integrate cortical information with dopamine-signaled value to mediate action selection among available behavioral options. Medium spiny neurons are components of either the direct or indirect striatal output pathways. Selective activation of indirect pathway medium spiny neurons by dopamine D2 receptor antagonists is putatively a key element in the mechanism of their antipsychotic efficacy. While PDE10A is expressed in all medium spiny neurons, studies in rodents indicated that PDE10A inhibition has behavioral effects in several key assays that phenocopy dopamine D2 receptor inhibition. This finding gave rise to the hypothesis that PDE10A inhibition also preferentially activates indirect pathway medium spiny neurons, a hypothesis that is consistent with electrophysiological, neurochemical, and molecular effects of PDE10A inhibitors. These data underwrote industry-wide efforts to investigate and develop PDE10A inhibitors as novel antipsychotics. Disappointingly, PDE10A inhibitors from 3 companies failed to evidence antipsychotic activity in patients with schizophrenia to the same extent as standard-of-care D2 antagonists. Given the notable similarities between PDE10A inhibitors and D2 antagonists, gaining an understanding of why only the latter class is antipsychotic affords a unique window into the basis for this therapeutic efficacy. With this in mind, we review the data on PDE10A inhibition as a step toward back-translating the limited antipsychotic efficacy of PDE10A inhibitors, hopefully to inform new efforts to develop better therapeutics to treat psychosis and schizophrenia.

The Tail of the Striatum: From Anatomy to Connectivity and Function

The dorsal striatum, the largest subcortical structure of the basal ganglia, is critical in controlling motor, procedural, and reinforcement-based behaviors. Although in mammals the striatum extends widely along the rostro-caudal axis, current knowledge and derived theories about its anatomo-functional organization largely rely on results obtained from studies of its rostral sectors, leading to potentially oversimplified working models of the striatum as a whole. Recent findings indicate that the extreme caudal part of the striatum, also referred to as the tail of striatum (TS), represents an additional functional domain. Here, we provide an overview of past and recent studies revealing that the TS displays a heterogeneous cell-type-specific organization, and a unique input-output connectivity, which poises the TS as an integrator of sensory processing.

Concurrent amygdalar and ventromedial prefrontal cortical responses during emotion processing: a meta-analysis of the effects of valence of emotion and passive exposure versus active regulation

Anatomically interconnected, the ventromedial prefrontal cortex (vmPFC) and amygdala interact in emotion processing. However, no meta-analyses have focused on studies that reported concurrent vmPFC and amygdala activities. With activation likelihood estimation (ALE) we examined 100 experiments that reported concurrent vmPFC and amygdala activities, and distinguished responses to positive vs. negative emotions and to passive exposure to vs. active regulation of emotions. We also investigated whole-brain experiments for other regional activities. ALE and contrast analyses identified convergent anterior and posterior vmPFC response to passive positive and negative emotions, respectively, and a subregion in between to mixed emotions. A smaller area in the posterior ventral vmPFC is specifically involved in regulation of negative emotion. Whereas bilateral amygdala was involved during emotional exposure, only the left amygdala showed convergent activities during active regulation of negative emotions. Whole-brain analysis showed convergent activity in left ventral striatum for passive exposure to positive emotions and downregulation of negative emotions, and in the posterior cingulate cortex and ventral precuneus for passive exposure to negative emotions. These findings highlight contrasting, valence-specific subregional vmPFC as well as other regional responses during passive exposure to emotions. The findings also suggest that hyperactivation of the vmPFC is associated with diminished right amygdala activities during regulation of negative emotions. Together, the findings extend the literature by specifying the roles of subregional vmPFC and amygdala activities in emotion processing.

Contrasting patterns of ERK activation in the tail of the striatum in response to aversive and rewarding signals

The caudal part of the striatum, also named the tail of the striatum (TS), defines a fourth striatal domain. Determining whether rewarding, aversive and salient stimuli regulate the activity of striatal spiny projections neurons (SPNs) of the TS is therefore of paramount importance to understand its functions, which remain largely elusive. Taking advantage of genetically encoded biosensors (A-kinase activity reporter 3) to record protein kinase A signals and by analyzing the distribution of dopamine D1R- and D2R-SPNs in the TS, we characterized three subterritories: a D2R/A2aR-lacking, a D1R/D2R-intermingled and a D1R/D2R-SPNs-enriched area (corresponding to the amygdalostriatal transition). In addition, we provide evidence that the distribution of D1R- and D2R-SPNs in the TS is evolutionarily conserved (mouse, rat, gerbil). The in vivo analysis of extracellular signal-regulated kinase (ERK) phosphorylation in these TS subterritories in response to distinct appetitive, aversive and pharmacological stimuli revealed that SPNs of the TS are not recruited by stimuli triggering innate aversive responses, fasting, satiety, or palatable signals whereas a reduction in ERK phosphorylation occurred following learned avoidance. In contrast, D1R-SPNs of the intermingled and D2R/A2aR-lacking areas were strongly activated by both D1R agonists and psychostimulant drugs (d-amphetamine, cocaine, 3,4-methyl enedioxy methamphetamine, or methylphenidate), but not by hallucinogens. Finally, a similar pattern of ERK activation was observed by blocking selectively dopamine reuptake. Together, our results reveal that the caudal TS might participate in the processing of specific reward signals and discrete aversive stimuli. Cover Image for this issue: doi: 10.1111/jnc.14526. Open Science: This manuscript was awarded with the Open Materials Badge For more information see: https://cos.io/our-services/open-science-badges/.