Global trends of purinergic receptors and depression:A bibliometric analysis from 2003 to 2023

BACKGROUND Depression significantly threatens human health.Purinergic receptors are reported to be associated with depression.However,there is no bibliometric research in this field have been published.AIM To provide some reference for the further research in the field of purinergic receptors and depression utilizing bibliometric analysis.METHODS Relevant researches were retrieved from the Web of Science Core Collection database.The period of the search was from January 1,2003 to December 31,2023.The CiteSpace(6.2.R7)and VOSviewer(1.6.19)were applied to identify the main contributors of countries,authors,institutions,references and journals.Besides,we evaluate keywords to assess the hotspots and trends over the previous 2 decades.RESULTS Totally,247 articles were identified,showing an increasing trend over time.The most productive country,institution,and journal in this field are China,Harvard University,and Biological Psychiatry,respectively.Liang SD and Rodrigues,Ana Lucia S were the most prolific authors.Burnstock G ranked first among the cited authors.The cooperation among countries and disciplines is crucial.The P2X7 receptor provides promising prospects for treating depression and further studies are warranted to validate the scope and significance of depression therapeutic strategies.CONCLUSION This study provides an overview of the worldwide research status and future trends in purinergic receptors and depression.P2X7 receptor is considered an appropriate target for the treatment of depression,as well as neurological diseases.It is implied that based on purinergic system,the future prospects for interventions aimed at depression treatment are promising,showing the way for both augmentation strategies and new drug treatments in the context of the pharmacology of depression.

WJSC 6^(th) Anniversary Special Issues(2):Mesenchymal stem cells Purinergic receptors and nucleotide processing ectoenzymes:Their roles in regulating mesenchymal stem cell functions

Human mesenchymal stem cells(MSCs)are a rare population of non-hematopoietic stem cells with multilineage potential,originally identified in the bone marrow.Due to the lack of a single specific marker,MSCs can be recognized and isolated by a series of features such as plastic adherence,a panel of surface markers,the clonogenic and the differentiation abilities.The recognized role of MSCs in the regulation of hemopoiesis,in cell-degeneration protection and in the homeostasis of mesodermal tissues through their differentiation properties,justifies the current interest in identifying the biochemical signals produced by MSCs and their active crosstalk in tissue environments.Only recently have extracellular nucleotides(eNTPs)and their metabolites been included among the molecular signals produced by MSCs.These molecules are active on both ionotropic and metabotropic receptors present in most cell types.MSCs possess a significant display of these receptors and of nucleotide processing ectoenzymes on their plasma membrane.Thus,from their niche,MSCs give a significant contribution to the complex signaling network of eNTPs and its derivatives.Recent studies have demonstrated the multifaceted aspects of eNTP metabolism and their signal transduction in MSCs and revealed important roles in specifying differentiation lineages and modulating MSC physiology and communication with other cells.This review discusses the roles of eNTPs,their receptors and ectoenzymes,and the relevance of the signaling network and MSC functions,and also focuses on the importance of this emerging area of interest for future MSC-based cell therapies.

The role of purinergic receptors in neural repair and regeneration after spinal cord injury

Spinal cord injury is a serious injury of the central nervous system that results in neurological deficits.The pathophysiological mechanisms underlying spinal cord injury,as well as the mechanisms involved in neural repair and regeneration,are highly complex.Although there have been many studies on these mechanisms,there is no effective intervention for such injury.In spinal cord injury,neural repair and regeneration is an important part of improving neurological function after injury,although the low regenerative ability of nerve cells and the difficulty in axonal and myelin regeneration after spinal cord injury hamper functional recovery.Large amounts of ATP and its metabolites are released after spinal cord injury and participate in various aspects of functional regulation by acting on purinergic receptors which are widely expressed in the spinal cord.These processes mediate intracellular and extracellular signalling pathways to improve neural repair and regeneration after spinal cord injury.This article reviews research on the mechanistic roles of purinergic receptors in spinal cord injury,highlighting the potential role of purinergic receptors as interventional targets for neural repair and regeneration after spinal cord injury.

Uridine adenosine tetraphosphate acts as a pro-angiogenic factor in vitrothrough purinergic P2Y receptors

OBJECTIVE Uridine adenosine tetraphosphate(Up4A),a dinucleotide,contains both purine and pyrimidine moieties,and exerts its vascular influence via activation of purinergic receptors.Here,we aimed to investigate the effects of Up4 A on angiogenesis and the putative purinergic receptors(PR)involved in this process.METHODS Tubule formation assay was performed in 3D matrix system.In this assay,human umbilical vein endothelial cells(HUVECs)were co-cultured with pericytes with various Up4 A doses(0,1,2.5,5,10 and 20μmol·L-1)in the absence and presence of P2Y6 R antagonist MRS2578(10μmol·L-1)for 5d.Expression profile of PR subtypes and angiogenic factors was assessed in HUVECs by q-PCR with and without P2Y6 R antagonist.RESULTS No difference in initial tubule formation was detected between Up4 A stimulation and control conditions at day 2.In contrast,a significant increase in vascular density in response to Up4 A was observed at day 5.Up4 A at a dose of 2.5and 5μmol·L-1 promoted total tubule length(by-1.89 fold and-2.23fold),number of tubules(by-1.71 fold and-1.89fold)as well as number of junctions(by-2.24 fold and-2.80fold),all of which were inhibited by MRS2578.Further increase in Up4 A dose to10 and 20μmol·L-1 did not induce an increase in these vascular parameters as compared to non-treated controls.Moreover,Up4 A increased mRNA level of P2YRs(P2Y2R,P2Y4 R and P2Y6R)but not P2XR(P2X4R and P2X7R)or P1R(A2AR and A2BR),while Up4 A upregulated VEGFA and ANGPT1 but not VEGFR2,ANGPT2,Tie1 and Tie2at mRNA level.Transcriptional upregulation of P2 YRs and angiogenic factors by Up4 A was inhibited by MRS2578.CONCLUSION Up4 A is functionally capable of promoting tubule formation in vitro co-culture system.This process is likely mediated by activation of pyrimidine-favored P2 YRs but not P2 XR or P1 Rs,and involves stimulation of well known angiogenic factors.

THE ROLE OF P_1-PURINERGIC RECEPTORS IN THE SPINAL MECHANISMS OF ACUPUNCTURE ANALGESIA

It has been extensively proved that electro-acupuncture elicit analgesia in bothextensive areas and local region via supraspinal structures and spinal cord.The present investigationwas to study the role of P1-purinergic receptors in the spinal mechanisms of weak electroacupuncture-induced analgesia.Leg withdrawal latency（LWL）to noxious radiant heat focused on the ankle regionwas used to assess the effects of acupuncture and that of P1-purinergic（adenosine）receptor antago-nists,theophylline and caffeine on the electro-acupuncture（EA）analgesia.EA prolonged the LWLby 16.7%±20.3%,with an after-effect lasting about 15 min.Both theophylline and caffeineblocked the EA-induced prolongation of LWL in a dose-dependent manner at the doses of 1.6-16 mg/kg.These results suggest that P1-purinegic receptor is involved in the spinal mechanisms of weak EAproduced analgesia in the rat.

Genomic Organization of Purinergic P2X Receptors

Purinergic P2X receptors are a family of ligand-gated cationic channels activated by extracellular ATP. P2X subunit protein sequences are highly conserved between vertebrate species. However, they can generate a great diversity of coding splicing variants to fulfill several roles in mammalian physiology. Despite intensive research in P2X expression in both central and peripheral nervous system, there is little information about their homology, genomic structure and other key features that can help to develop selective drugs or regulatory strategies of pharmacological value which are lacking today. In order to obtain clues on mammalian P2X diversity, we have performed a bioinformatics analysis of the coding regions and introns of the seven P2X subunits present in human, simian, dog, mouse, rat and zebrafish. Here we report the arrangements of exon and intron sequences, considering its number, size, phase and placement;proposing some ideas about the gain and loss of exons and retention of introns. Taken together, these evidences show traits that can be used to gain insight into the evolutionary history of vertebrate P2X receptors and better understand the diversity of subunits coding the purinergic signaling in mammals.

Olfactory receptors in neural regeneration in the central nervous system

Olfactory receptors are crucial for detecting odors and play a vital role in our sense of smell,influencing behaviors from food choices to emotional memories.These receptors also contribute to our perception of flavor and have potential applications in medical diagnostics and environmental monitoring.The ability of the olfactory system to regenerate its sensory neurons provides a unique model to study neural regeneration,a phenomenon largely absent in the central nervous system.Insights gained from how olfactory neurons continuously replace themselves and reestablish functional connections can provide strategies to promote similar regenerative processes in the central nervous system,where damage often results in permanent deficits.Understanding the molecular and cellular mechanisms underpinning olfactory neuron regeneration could pave the way for developing therapeutic approaches to treat spinal co rd injuries and neurodegenerative diseases like Alzheimer's disease.Olfa ctory receptors are found in almost any cell of eve ry orga n/tissue of the mammalian body.This ectopic expression provides insights into the chemical structures that can activate olfactory receptors.In addition to odors,olfactory receptors in ectopic expression may respond to endogenous compounds and molecules produced by mucosal colonizing microbiota.The analysis of the function of olfactory receptors in ectopic expression provides valuable information on the signaling pathway engaged upon receptor activation and the receptor's role in proliferation and cell differentiation mechanisms.This review explo res the ectopic expression of olfa ctory receptors and the role they may play in neural regeneration within the central nervous system,with particular attention to compounds that can activate these receptors to initiate regenerative processes.Evidence suggests that olfactory receptors could serve as potential therapeutic targets for enhancing neural repair and recovery following central nervous system injuries.

Cortico-striatal gamma oscillations are modulated by dopamine D3 receptors in dyskinetic rats

Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Currently,studies have reported increased oscillation power in cases of levodopa-induced dyskinesia.However,little is known about how the other electrophysiological parameters of gamma oscillations are altered in levodopa-induced dyskinesia.Furthermore,the role of the dopamine D3 receptor,which is implicated in levodopa-induced dyskinesia,in movement disorder-related changes in neural oscillations is unclear.We found that the cortico-striatal functional connectivity of beta oscillations was enhanced in a model of Parkinson’s disease.Furthermore,levodopa application enhanced cortical gamma oscillations in cortico-striatal projections and cortical gamma aperiodic components,as well as bidirectional primary motor cortex(M1)↔dorsolateral striatum gamma flow.Administration of PD128907(a selective dopamine D3 receptor agonist)induced dyskinesia and excessive gamma oscillations with a bidirectional M1↔dorsolateral striatum flow.However,administration of PG01037(a selective dopamine D3 receptor antagonist)attenuated dyskinesia,suppressed gamma oscillations and cortical gamma aperiodic components,and decreased gamma causality in the M1→dorsolateral striatum direction.These findings suggest that the dopamine D3 receptor plays a role in dyskinesia-related oscillatory activity,and that it has potential as a therapeutic target for levodopa-induced dyskinesia.

Metabotropic glutamate receptors(mGluRs)in epileptogenesis:an update on abnormal mGluRs signaling and its therapeutic implications

Epilepsy is a neurological disorder characterized by high morbidity,high recurrence,and drug resistance.Enhanced signaling through the excitatory neurotransmitter glutamate is intricately associated with epilepsy.Metabotropic glutamate receptors(mGluRs)are G protein-coupled receptors activated by glutamate and are key regulators of neuronal and synaptic plasticity.Dysregulated mGluR signaling has been associated with various neurological disorders,and numerous studies have shown a close relationship between mGluRs expression/activity and the development of epilepsy.In this review,we first introduce the three groups of mGluRs and their associated signaling pathways.Then,we detail how these receptors influence epilepsy by describing the signaling cascades triggered by their activation and their neuroprotective or detrimental roles in epileptogenesis.In addition,strategies for pharmacological manipulation of these receptors during the treatment of epilepsy in experimental studies is also summarized.We hope that this review will provide a foundation for future studies on the development of mGluR-targeted antiepileptic drugs.

The bumpy road of purinergic inhibitors to clinical application in immune-mediated diseases

Purinergic signaling plays important roles throughout the body in the regulation of organ functions during and following the disruption of homeostasis.This is also reflected by the widespread expression of two families of purinergic receptors(P1 and P2)with numerous subtypes.In the last few decades,there has been increasing evidence that purinergic signaling plays an important role in the regulation of immune functions.Mainly,signals mediated by P2 receptors have been shown to contribute to immune system-mediated pathologies.Thus,interference with P2 receptors may be a promising strategy for the modulation of immune responses.Although only a few clinical studies have been conducted in isolated entities with limited success,preclinical work suggests that the use of P2 receptor inhibitors may bear some promise in various autoimmune diseases.Despite the association of P2 receptors with several disorders from this field,the use of P2 receptor antagonists in clinical therapy is still very scarce.In this narrative review,we briefly review the involvement of the purinergic system in immunological responses and clinical studies on the effect of purinergic inhibition on autoimmune processes.We then open the aperture a bit and show some preclinical studies demonstrating a potential effect of purinergic blockade on autoimmune events.Using suramin,a non-specific purinergic inhibitor,as an example,we further show that off-target effects could be responsible for observed effects in immunological settings,which may have interesting implications.Overall,we believe that it is worthwhile to further investigate this hitherto underexplored area.

Immunomodulation of Proton-activated G Protein-coupled Receptors in Inflammation

Proton-activated G protein-coupled receptors(GPCRs),initially discovered by Ludwig in 2003,are widely distributed in various tissues.These receptors have been found to modulate the immune system in several inflammatory diseases,including inflammatory bowel disease,atopic dermatitis,and asthma.Proton-activated GPCRs belong to the G protein-coupled receptor family and can detect alternations in extracellular pH.This detection triggers downstream signaling pathways within the cells,ultimately influencing the function of immune cells.In this review,we specifically focused on investigating the immune response of proton-activated GPCRs under inflammatory conditions.

Characterization of Domeless receptors and the role of Bd Domeless3 in anti-symbiont-like virus defense in Bactrocera dorsalis

The Janus kinase/signal transducers and activators of transcription(JAK/STAT)signaling pathway play a pivotal role in innate immunity.Among invertebrates,Domeless receptors serve as the key upstream regulators of this pathway.In our study on Bactrocera dorsalis,we identified three cytokine receptors:BdDomeless1,BdDomeless2,and BdDomeless3.Each receptor encompasses five fibronectin-type-III-like(FN III)extracellular domains and a transmembrane domain.Furthermore,these receptors exhibit the increased responsiveness to diverse pathogenic challenges.Notably,only BdDomeless3 is upregulated during symbiont-like viral infections.Moreover,silencing BdDomeless3 enhanced the infectivity of Bactrocera dorsalis cripavirus(BdCV)and B.dorsalis picorna-like virus(BdPLV),underscoring BdDomeless3’s crucial role in antiviral defense of B.dorsalis.Following the suppression of Domeless3 expression,six antimicrobial peptide genes displayed decreased expression,potentially correlating with the rise in viral infectivity.To our knowledge,this is the first study identifying cytokine receptors associated with the JAK/STAT pathway in tephritid flies,shedding light on the immune mechanisms of B.dorsalis.

The Role of Toll-Like Receptors and Nuclear Factor κB p65 Protein in the Pathogenesis of Otitis Media

The role of Toll-like receptor 4 (TLR4) and nuclear factor κB p65 (NF-κB p65) proteins in the pathogenesis of otitis media is explored. In recent years, the incidence of otitis media has been rising globally, becoming a significant threat to human health. More and more studies have found that Toll-like receptor 4 (TLR4), as a member of the Toll-like receptor family, can promote the generation of inflammatory factors and is closely related to the body’s immune response and inflammatory response. Nuclear factor-κB p65 (NF-κB p65) is a nuclear transcription factor that can interact with various cytokines, growth factors, and apoptotic factors, participating in processes such as oxidative stress, apoptosis, and inflammation in the body [1]. This article elaborates on the structure, function, and signaling pathways of TLR4 and NF-κB p65 proteins in the pathogenesis of otitis media, aiming to provide more precise targets and better therapeutic efficacy for the diagnosis and treatment of otitis media. The role of inflammation in disease.

Toll-like receptors 2 polymorphism is associated with psoriasis: A case-control study in the northern Chinese population

Background:Psoriasis is a disease caused by genetics and immune system dysfunction,affecting the skin and joints.Toll-like receptors(TLRs)play an important role in triggering the innate immune response and controlling adaptive immunity.The role of TLR2 in the progression of psoriasis is not well understood.Methods:A case-control study was conducted on a northern Chinese Han population,consisting of psoriasis patients and healthy control subjects.Genotyping was performed using the tetra-primer amplification refractory mutation system-polymerase chain reaction(ARMS-PCR),and allele and genotype frequencies of four SNPs in TLR2 were analyzed in 270 psoriasis patients and 246 healthy controls.Results:Four TLR2 SNPs(rs11938228,rs4696480,rs3804099,rs5743699)were genotyped and found to be in linkage disequilibrium.The genotype distributions of rs11938228 and rs4696480 in two groups were in Hardy-Weinberg equilibrium and statistically significant except for the overdominance model.The haplotypes ATTC and ATCC were found to be protective against psoriasis.Conclusion:Our study found a correlation between TLR2 genetic variations and the likelihood of psoriasis in northern China.

Nuclear receptors and pathogenesis of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a median overall survival time of 5 mo and the five years survival less than 5%, a rate essentially unchanged over the course of the years. A well defined progression model of accumulation of genetic alterations ranging from single point mutations to gross chromosomal abnormalities has been introduced to describe the origin of this disease. However, due to the its subtle nature and concurring events PDAC cure remains elusive. Nuclear receptors (NR) are members of a large superfamily of evolutionarily conserved ligand-regulated DNA-binding transcription factors functionally involved in important cellular functions ranging from regulation of metabolism, to growth and development. Given the nature of their ligands, NR are very tempting drug targets and their pharmacological modulation has been widely exploited for the treatment of metabolic and inflammatory diseases. There are now clear evidences that both classical ligand-activated and orphan NR are involved in the pathogenesis of PDAC from its very early stages; nonetheless many aspects of their role are not fully understood. The purpose of this review is to highlight the striking connections that link peroxisome proliferator activated receptors, retinoic acid receptors, retinoid X receptor, androgen receptor, estrogen receptors and the orphan NR Nur, chicken ovalbumin upstream promoter transcription factor II and the liver receptor homologue-1 receptor to PDAC development, connections that could lead to the identification of novel therapies for this disease.

Fluorescent probes for imaging and detection of plant hormones and their receptors

Exploring plant behavior at the cellular scale in a minimally invasive manner is critical to understanding plant adaptation to the environment.Phytohormones play vital regulatory roles in multiple aspects of plant growth and development and acclimation to environmental changes.Since the biosynthesis,modification,transportation,and degradation of plant hormones in plants change with time and space,their content level and distribution are highly dynamic.To monitor the production,transport,perception,and distribution of phytohormones within undamaged tissues,we require qualitative and quantitative tools endowed with remarkably high temporal and spatial resolution.Fluorescent probes are regarded as excellent tools for widespread plant imaging because of their high sensitivity and selectivity,reproducibility,real-time in situ detection,and uncomplicated mechanism elucidation.In this review,we provide a systematical overview of the progress in the sensing and imaging of phytohormone fluorescent probes and fluorescently labeled phytohormones to their receptors in plants.Moreover,forthcoming viewpoints and possible applications of these fluorescent probes within the realm of plants are also presented.We hold the conviction that the new perspective brought by this paper can promote the development of fluorescent probes,enabling them to have better detection performance in plant hormone imaging.

Contribution of altered signal transduction associated to glutamate receptors in brain to the neurological alterations of hepatic encephalopathy

Patients with liver disease may present hepatic enceph- alopathy (HE), a complex neuropsychiatric syndrome covering a wide range of neurological alterations, including cognitive and motor disturbances. HE reduces the quality of life of the patients and is associated with poor prognosis. In the worse cases HE may lead to coma or death. The mechanisms leading to HE which are not well known are being studied using animal models. The neurological alterations in HE are a consequence of impaired cerebral function mainly due to alterations in neurotransmission. We review here some studies indicating that alterations in neurotransmission associated to different types of glutamate receptors are responsible for some of the cognitive and motor alterations present in HE. These studies show that the function of the signal transduction pathway glutamate-nitric oxide-cGMP associated to the NMDA type of glutamate receptors is impaired in brain in vivo in HE animal models as well as in brain of patients died of HE. Activation of NMDA receptors in brain activates this pathway and increases cGMP. In animal models of HE this increase in cGMP induced by activation of NMDA receptors is reduced, which is responsible for the impairment in learning ability in these animal models. Increasing cGMP by pharmacological means restores learning ability in rats with HE and may be a new therapeutic approach to improve cognitive function in patients with HE. However, it is necessary to previously assess the possible secondary effects.Patients with HE may present psychomotor slowing, hypokinesia and bradykinesia. Animal models of HE also show hypolocomotion. It has been shown in rats with HE that hypolocomotion is due to excessive activation of metabotropic glutamate receptors (mGluRs) in substantia nigra pars reticulata. Blocking mGluR1 in this brain area normalizes motor activity in the rats, suggesting that a similar treatment for patients with HE could be useful to treat psychomotor slowing and hypokinesia. However, the possible secondary effects of mGluR1 antagonists should be previously evaluated. These studies are setting the basis for designing therapeutic procedures to specifically treat the individual neurological alterations in patients with HE.

Melanocortin 3,5 receptors immunohistochemical expression in colonic mucosa of inflammatory bowel disease patients:A matter of disease activity?

BACKGROUND Melanocortin 3 and 5 receptors(i.e.,MC3R and MC5R)belong to the melanocortin family.However,data regarding their role in inflammatory bowel diseases(IBD)are currently unavailable.AIM This study aims to ascertain their expression profiles in the colonic mucosa of Crohn’s disease(CD)and ulcerative colitis(UC),aligning them with IBD disease endoscopic and histologic activity.METHODS Colonic mucosal biopsies from CD/UC patients were sampled,and immunohisto-chemical analyses were conducted to evaluate the expression of MC3R and MC5R.Colonic sampling was performed on both traits with endoscopic scores(Mayo endoscopic score and CD endoscopic index of severity)consistent with inflamed mucosa and not consistent with disease activity(i.e.,normal appearing mucosa).RESULTS In both CD and UC inflamed mucosa,MC3R(CD:+7.7 fold vs normal mucosa,P<0.01;UC:+12 fold vs normal mucosa,P<0.01)and MC5R(CD:+5.5 fold vs normal mucosa,P<0.01;UC:+8.1 fold vs normal mucosa,P<0.01)were significantly more expressed compared to normal mucosa.CONCLUSION MC3R and MC5R are expressed in the colon of IBD patients.Furthermore,expression may differ according to disease endoscopic activity,with a higher degree of expression in the traits affected by disease activity in both CD and UC,suggesting a potential use of these receptors in IBD pharmacology.

Role of bitter contributors and bitter taste receptors:a comprehensive review of their sources,functions and future development

Bitterness,one of the 5“basic tastes”,is usually undesired by humans.However,abundant literature reported that bitter fruits and vegetables have beneficial health effects due to their bitter contributors.This review provided an updated overview of the main bitter contributors of typical bitter fruits and vegetables and their health benefits.The main bitter contributors,including phenolics,terpenoids,alkaloids,amino acids,nucleosides and purines,were summarized.The bioactivities and wide range of beneficial effects of them on anti-cancers,anti-inflammations,anti-microbes,neuroprotection,inhibiting chronic and acute injury in organs,as well as regulating behavior performance and metabolism were reported.Furthermore,not only did the bitter taste receptors(taste receptor type 2 family,T2Rs)show taste effects,but extra-oral T2Rs could also be activated by binding with bitter components,regulating physiological activities via modulating hormone secretion,immunity,metabolism,and cell proliferation.This review provided a new perspective on exploring and explaining the nutrition of bitter foods,revealing the relationship between the functions of bitter contributors from food and T2Rs.Future trends may focus on revealing the possibility of T2Rs being targets for the treatment of diseases,exploring the mechanism of T2Rs mediating the bioactivities,and making bitter foods more acceptable without getting rid of bitter contributors.

Insights into the structural biology of G-protein coupled receptors impacts drug design for central nervous system neurodegenerative processes

In the last few years, there have been important new insights into the structural biology of G-protein coupled receptors. It is now known that allosteric binding sites are involved in the affinity and selec- tivity of ligands for G-protein coupled receptors, and that signaling by these receptors involves both G-protein dependent and independent pathways. The present review outlines the physiological and pharmacological implications of this perspective for the design of new drugs to treat disorders of the central nervous system. Specifically, new possibilities are explored in relation to allosteric and or- thosteric binding sites on dopamine receptors for the treatment of Parkinson＇s disease, and on muscarinic receptors for Alzheimer＇s disease. Future research can seek to identify ligands that can bind to more than one site on the same receptor, or simultaneously bind to two receptors and form a dimer. For example, the design of bivalent drugs that can reach homo/hetero-dimers of D2 dopa- mine receptor holds promise as a relevant therapeutic strategy for Parkinson＇s disease. Regarding the treatment of Alzheimer＇s disease, the design of dualsteric ligands for mono-oligomeric mus- carinic receptors could increase therapeutic effectiveness by generating potent compounds that could activate more than one signaling pathway.