Neuropharmacology of Alcohol Addiction with Special Emphasis on Proteomic Approaches for Identification of Novel Therapeutic Targets
INTRODUCTION Alcohol consumption is commonplace in many societies. These cultures pay a high price for the benefits connected with the production, sale, and consumption of alcoholic beverages . Alcohol-related disorders, including alcohol use disorder (AUD), result from a person's genetic make-up, cumulative responses to alcohol exposure, and environmental perturbations over time. Alcohol consumption can become compulsive and eventually addictive, depending on many modifying factors, for instance, genetic predisposition, provoking environmental events, social context, pharmaceutical history, and others . Associated psychiatric problems, for example, anxiety and, foremost depressive disorders, are genetically established nonspecific susceptibility factors that significantly raise the likelihood of increasing alcohol addiction . AUD is defined as a chronic and progressive disorder characterized by the development of alcohol tolerance, alcohol dependence ( i.e ., uncontrolled intake of alcohol even though negative consequences), and craving and/or removal syndrome once alcohol is detached. Furthermore, the pharmacokinetics of alcohol is determined by several mechanisms. It is generally known that genes with a significant impact on alcohol metabolism influence how people react to alcohol and how likely they are to develop an addiction to it . According to current research, acetaldehyde's contribution to alcohol's effects is finest described by a procedure in which acetaldehyde regulates, rather than intercedes, some of the effects of alcohol . Long-term, uncontrolled alcohol usage can lead to antisocial personality disorder, as well as mood and anxiety issues. For more than a century, scientists have been studying the mechanisms that underpin ethanol's activities in the central nervous system (CNS). The Meyer-Overton connection defines the straight association between an alcohol's hydrophobicity and its potency for creating intoxication . An early study on the effects of alcohol focused on physical qualities of alcohol and created the highly acclaimed Meyer-Overton relation. Alcohol affects the activity of several neurotransmitter receptors ( e.g ., acetylcholine, glutamate, GABAA, nor-epinephrine, glycine, dopamine, and serotonin) and transporters ( e.g ., dopamine, adenosine, serotonin, nor-epinephrine) . Recent research has revealed that gene regulation is significantly more complex than formerly thought and does not fully clarify changes in protein levels. As a result, direct study of the proteome, which differs significantly from the genome/transcriptome in complexity and dynamicity, has yielded distinctive insights to many investigators . Neuroproteomics has the potential to revolutionize alcohol research by allowing researchers to gain a better knowledge of how alcohol impacts protein structure, function, connections, and networks on a global scale . The Neuroproteomic workflow of the alcohol model (human sample and some parts from bioinformatics approach using human data) is shown in Fig. . These discoveries have yielded a plethora of information that can be used to find essential biomarkers for initial detection and improved prognosis of AUD, as well as prospective pharmacological targets for the treatment of this addiction. Furthermore, multidimensional approaches to addiction, for instance, the planned addictions neuroclinical assessment (ANA), could be utilized to discover new addiction biomarkers and refine existing ones . This article discusses some of the core neurobiological underpinnings of alcohol addiction, focusing on neuroproteomics. In addition, the essay discusses the latest findings on identifying novel treatment targets and proteomic biomarkers for alcohol addiction.   INITIATION AND MAINTENANCE OF ALCOHOL CONSUMPTION The onset of alcohol use is primarily impacted by an individual's biological (genetically determined) traits . Multiple genetic factors determine the level of sensitivity to alcohol and the resulting intoxication stop indication . A range of neuropharmacological research, including lesion, microinjection, and microdialysis tests, found brain areas that assist an essential part in facilitating the reinforcing effects of alcohol . Glutamatergic activity affects a significant portion of the mesolimbic DAergic pathway . Additionally, the dorsal raphe nucleus 5-hydroxy-tryptamine (5-HT) system influences the ventral tegmental area (VTA) and nucleus accumbens (NAC) DAergic activity . Aside from these physiologically and genetically defined reactions (early sensitivity, alcohol reinforcement) to a severe alcohol challenge in alcohol-drunk individuals (Fig. ), environmental factors such as stress exposure have long been hypothesized to accelerate the initiation of alcohol use . Stressors are hypothesized to affect several neurobiological systems, including hypothalamic-pituitary–adrenal axis and additional hypothalamic corticotropin-releasing factor (CRF) signalling . 5-hydroxytryptamine (5-HT) acts on diverse 5-HT receptor subtypes to modify glutamate and GABA-mediated actions . 5-HT can influence neurotransmitter release at the pre-synaptic level; for example, 5-HT1A, 5-HT1B, and 5-HT6 receptors inhibit glutamate release in diverse brain areas . The amplitude of a T-type stumpy threshold voltage-dependent Ca 2+ current, which is accountable for rhythmic oscillations of membrane potential, is augmented by 5-HT and decreased by GABAB agonists in interneurons from the stratum lacunosum-molecolare of the CA1 area . The increased quantity and function of the N-methyl-D-aspartate receptor (NMDAR) is assumed to be a physiopathological state linked with alcohol withdrawal . NMDARs are ionotropic glutamate receptors that are widely expressed in CNS. In alcohol-treated primary cortical and hippocampal cultures, the NMDA-induced upsurge in cytosolic calcium level, along with NMDA-induced excitotoxicity, was observed to be potentiated. NMDARs are influenced by neurosteroids as well . Estrogen and pregnenolone sulfate (PS) was previously thought to directly affect NMDA receptors, increasing the incidence of first and mean open time of the ion channel. The unique characteristics of these receptors, such as high permeability to Ca 2+ ions, comparatively slow activation/deactivation kinetics, and voltage-sensitive obstacle by Mg 2+ ions, explain their involvement in miscellaneous neural functions such as excitatory synaptic transmission, synaptic plasticity, and excitotoxicity . Alcohol misuse induces significant brain neuroadaptations that lead to tolerance, dependence, and behavioral changes. The study of the protein complexes and species that make up the nervous system is known as neuroproteomics. In terms of profiling the entire neural proteome, neuroproteomics is a complicated field with a long way to go. Multiple neuroadaptations in the brain, comprising extensive modifications in gene/protein expression patterns, contribute to alcohol addiction, tolerance, and physical dependence, at least in part. The fact that alcoholism is a complex characteristic illness that affects numerous genes, even if each gene's effect is tiny, identifies these adaptations. Furthermore, here, 'omic' techniques have been widely used to investigate altered gene/protein expression patterns following excessive alcohol use in the brain. Although using miRNAomic, transcriptomic, and proteomic approaches in alcohol research have yielded a wealth of data, our knowledge of how individual expression changes interact to contribute to alcoholism remains restricted.   NEUROCHEMICAL SYSTEMS AND SIGNALING PATHWAYS INVOLVED IN THE ACTION OF ALCOHOL With increasing concentrations of alcohol, the intoxication signal ranges from disinhibition to sedation and even hypnosis, with the distinctive acute particular effects including the discriminative stimulus properties of alcohol, and connected with psychotropic effects, the intoxication signal extending from disinhibition to tranquility and even hypnosis occurs. A10 DA neurons in the midbrain are essential in beginning reinforcement processes . They start in the VTA and project to limbic system regions, most notably the NAC shell area and the prefrontal cortex (PFC). The VTA receives glutamatergic projections from PFC, stria terminals bed nucleus, laterodorsal tegmental nucleus, and lateral hypothalamus . Growth hormone secretagogue receptors (GHSR-1A), the efficient ghrelin receptor, are expressed in both locations, and there is cholinergic involvement from the laterodorsal tegmental area to the VTA. Alcohol dose-response curves for DA discharge in alcohol-naive, high-alcohol-drinking (HAD), and low-alcohol-drinking (LAD) cells exhibited no change in sensitivity to alcohol concerning the lines . In a separate investigation, “no-net-flux” quantitative microdialysis was used to assess the basal and ethanol-stimulated DA release in the NAC in the alcohol-naive HAD/ LAD model . Alcohol-induced activation of DAergic A10 neurons has been found to comprise central nACh and strychnine-sensitive glycine receptors, implying that these receptors can play a role in alcohol reinforcing . The most common substance use disorder, AUD, has a substantial global impact. After decades of attempts to find new treatment methods that have failed to deliver increased sobriety rates, relapse rates remain incredibly high. Excessive alcohol consumption negatively affects the CNS and may lead to AUDs. Current research suggests that myelin impairments may directly affect the CNS dysfunctions linked with AUDs. Electrical insulation and trophic support are provided by myelin, which is made up of compact lipid membranes that cover the axons. Because of its substantial effects on neural network computation, myelin regulation is seen as a unique form of brain plasticity. The endocannabinoid system appears to play a key role in the control of the rewarding characteristics of substances of abuse, including alcohol, according to mounting research. Orphan receptor G protein-coupled receptor 55 (GPR55), Cannabinoid type 1 receptor (CB1), and Cannabinoid type 2 receptor (CB2) a novel CB receptors, as well as endocannabinoids such as 2-arachidonoylglycerol (2-AG) and anandamide, their biosynthetic and inactivating enzymes, and maybe endocannabinoid transporters, make up the endocannabinoid system . CB1 receptor activation is required for alcohol reinforcing mechanisms. Although few studies have shown that acute ethanol administration upsurge proopiomelanocortin (POMC) mRNA in the arcuate nucleus, others have been incapable of finding any outcome of acute ethanol on arcuate POMC mRNA content, it is uncertain whether the ethanol-induced escalation in extracellular NAC endorphin levels is a consequence of direct activation of the arcuate-NAC endorphin pathway. D1-like receptors , which comprise the DA D1 and D5 receptors, boost adenylyl cyclase (AC) activity by connecting to stimulatory G proteins (Gs). D2-like receptors (D2-D4), on the other hand, block AC through inhibitory G proteins (Gi). The stimulation of D1-like receptors causes a rise in cAMP levels and the stimulation of cAMP-dependent protein kinase A (PKA) signalling, which leads to substrate phosphorylation. The transcription factor cAMP response element-binding protein (CREB) is one of the substrates of PKA, which leads to enhanced transcription of genes with cAMP response elements (CRE) in their promoter region . Voluntary alcohol consumption reduces Ca 2+ /calmodulin-dependent protein kinase IV (CaMKIV) expression and CREB phosphorylation, particularly in the shell of NAC, implying that reduced CaMKIV-dependent CREB phosphorylation in the shell region of NAC is implicated in alcohol reinforcing . Dopamine- and cAMP-regulated neuronal phosphoprotein-32 (DARPP-32), a 32-kDa protein produced primarily on striatal medium spiny neurons, is likewise phosphorylated when D1 cAMP-PKA signalling is activated, in addition to CREB . It operates as a potent inhibitor of protein phosphatase-1 (PP1) in its phosphorylated state, making it a key regulator of DAergic signalling. nNOS/NO/cGMP/cGKII signalling has been linked to the effect of alcohol in pharmacological and knockout investigations . The nucleus accumbens medium spiny neurons receive an excitatory glutamatergic response from the forebrain and dopaminergic response from the ventral tegmental region. This integration point could be a site where glutamate receptors of the NMDA subtype increase drug reinforcement. In DARPP-32 experimental models, the alcohol sensitivity of NMDA receptors is not regulated by D1 receptors. Following activation of dopaminergic neurons in the ventral tegmental region, DARPP-32-mediated blunting of the response to alcohol initiates molecular changes that influence synaptic plasticity in this circuit, increasing the establishment of alcohol reinforcing.   EFFECTS OF ALCOHOL ON PROTEIN-PROTEIN INTERACTIONS AND NEUROPROTEOMICS The proteome is an organism's whole collection of proteins. It is much bigger and more complicated than the genome, the collection of genes that code for these proteins. External stimuli, such as alcohol consumption, can change the number of proteins and the post-translational changes they experience. When researching genes and encoded proteins affected by alcohol or that intervene in its effects, developments in proteomics offer considerable benefits over traditional molecular techniques. Investigators can use a high-throughput technique like this to survey many putative target molecules in an unbiased manner, deprived of knowing which molecules are involved. Chronic alcohol abuse can cause a variety of changes in brain function. Multiple brain regions have been proven to be damaged by alcohol, resulting in cognitive impairment and other abnormalities in brain function. When the brain's neural and behavioral adaptations to the continual presence of alcohol are disrupted, severe withdrawal symptoms can occur. Trans-splicing, differential gene splicing, post-translational alterations, and other processes result in a wide diversity of proteins. Phosphorylation is essential for NMDAR function modulation . Fyn and Src are two highly similar tyrosine kinases that have been involved in phosphorylating NR2 subunits on tyrosine residues on sites thus far . The development of long-term potentiation (LTP) in the CA1 area of the hippocampus increases NR2B phosphorylation, but inhibitors of Src tyrosine kinases stop LTP from occurring . Calcineurin regulates the activity of PP1  via dopamine and cAMP-regulated phosphoprotein by requiring calcium/calmodulin binding for activation . DARPP-32 is primarily expressed in the neostriatum's medium spiny dopaminergic neurons, and it is a crucial regulator of various processes, including NMDAR control . It was recently shown that in the presence of ethanol, the DARPP-32/PP1 cascade is a key regulating mechanism for neostriatal NMDARs. Some significant phenomena, including cell signalling, vesicular trafficking etc ., induced by alcohol etc ., are shown in Fig. , which ultimately ends with the alcohol addiction of an individual. The effects of alcohol on intracellular signalling pathways contribute to both acute and neuroadaptive responses to repeated alcohol intake. PKA is involved in learning and memory, and behavioral responses to alcoholic beverages. PKA is activated when cyclic adenosine monophosphate (cAMP) binds to the regulatory subunits, forcing them to dissociate from the catalytic subunits, which become active. Signals produced from lipid second messengers are facilitated by protein kinase C (PKC) family of serine-threonine kinases. PKC-related kinases, triggered by the tiny G-proteins Rac and Rho, have recently been classified as a subfamily. Alcohol has been discovered to promote tumor angiogenesis and accelerate tumor growth. In vitro and in vivo , alcohol increases the expression of vascular endothelial growth factor (VEGF) in mammary gland carcinoma cells. Mitogen-activated protein kinase (MAPK) family members and extracellular-signal-regulated kinases (ERKs) are serine-threonine protein kinases. A Ras–Raf–MEK signalling cascade is initiated by RTK or calcium influx through NMDA and voltage-gated calcium channels, activating ERKs. Dopamine and glutamate receptor activate ERK activity, and it may serve as a coincidence detector during the development of addiction, combining information about rewards and contextual information. Recent research has revealed that neuroproteomics can revolutionize alcohol research by allowing researchers to gain a better knowledge of how alcohol impacts protein structure, function, connections, and networks on a global scale . Names of a few proteins expressed in alcoholic cells are shown in Table . With recent breakthroughs in high-resolution mass spectroscopy (MS) and bioinformatics, concurrent quantitative analysis of hundreds of proteins is now possible. Proteomic techniques , such as two-dimensional (2D) electrophoresis , have been used to investigate the effects of alcohol exposure on cell cultures, and different proteomic approaches were used to study . Mutation in type 1 equilibrative nucleoside transporter (ENT1) have found to be related with increased alcohol consumption . Greater glutamate neurotransmission in the nucleus accumbens is linked to increased alcohol preference in these animals (NAC). A recent study employed 2-D fluorescence difference gel electrophoresis (2D-DIGE) to examine cerebral cortices and midbrains  that had been treated with chronic intermittent ethanol (CIE) two-bottle choice (2BC) paradigm, which causes substantial drinking and is one of the best available animal models for alcohol dependency. Diverse alcohol-sensitive brain areas from simple and hepatic cirrhosis-convoluted human alcoholics have been studied using global proteome techniques on the human post-mortem brain .   GENE TRANSCRIPTION AND EPIGENETIC EFFECTS MEDIATED BY ALCOHOL Recent research suggests that ethanol can cause epigenetic changes, such as histone acetylation and methylation, as well as hypo- and hypermethylation of DNA . This has sparked an innovative concern in alcohol research by revealing novel information on ethanol's actions at the nucleosomal level concerning gene expression along with pathophysiological effects . Changes in methylation and acetylation patterns caused by alcohol could lead to long-term changes in gene expression. Nevertheless, it is too early to say whether epigenetic changes in synuclein gene represent a biological switch that causes long-term brain maladaptations. ATP converts methionine to S-adenosyl-methionine (SAM). It can transfer methyl groups to cytosine residues in genomic DNA's CpG dinucleotide sequence. Homocysteine levels are commonly elevated in alcohol-dependent individuals, whether they are actively drinking alcoholics or are in the early stages of abstinence . Pharmacological specificity of medication action is characterized by site-specific effects inside the anatomical and cellular intricacy of the brain. The exact activation patterns of ethanol-evoked c-fos responses have been extensively examined, and they most likely reflect action via many neurotransmitter systems . After ethanol administration, stimulus-activated transcription can be detected using histochemistry to map CRE-mediated gene transcription in the brain of the CRE lacZ transgenic experimental model . Axon remodeling is aided by myelin-related genes, and the prefrontal cortex appears to be particularly vulnerable to the toxic effects of ethanol . Furthermore, research on animal models selected for diverse ethanol-related characteristics, such as penchant and tolerance, suggests that ethanol affects different sets of genes depending on the dose . Tenacious alcohol-induced gene expression changes have been postulated as a 'molecular switch' that might facilitate long-term brain adaptations and mal-adaptations, as well as disordered behavior .   SYNAPTIC, CELLULAR AND NEURONAL NETWORK EFFECTS INDUCED BY ALCOHOL The ability of all synapses to endure activity-dependent alterations in synaptic plasticity, which may be examined most successfully using electrophysiological methods in brain slices, is a universal trait of all synapses . Abuse of alcohol boosts the reactivity of DA neurons to glutamate by increasing synaptic strength, enhancing LTP, or preventing long-term depression (LTD), and, as a result, induces increased DA release in brain areas, for instance, the NAC and the prefrontal cortex . Changes in α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor subunit composition are linked to alcohol-induced synaptic strengthening in DA neurons in the ventral tegmental area (VTA). Incorporation of AMPA receptor subunit GluR1 increases alcohol-induced synaptic reinforcement, most likely by forming highly conductive, Ca 2+ -permeable GluR1 homomeric AMPA receptors, whereas GluR2-containing receptors reverse it . The activation of NMDA receptors is required for synaptic recruitment of GluR1 subunits and resulting synaptic potentiation. In the dorsomedial striatum, a striatal sub-region which plays a vital role in the acquisition and assortment of goal-focused activities, the effects of ethanol on long-standing synaptic plasticity have also been investigated . The processes of brain injury in alcohol-dependent people have been revealed using structural magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), spectroscopy, and positron emission tomography (PET) . Using graphic alcohol stimuli shows that a close relationship develops in teenagers with concise drinking histories, implying that the observed reaction to alcohol advertisements in teenagers with drinking issues has a neurological foundation. Measurable and noninvasive access to various metabolites in diverse brain areas in vivo is possible with proton magnetic resonance spectroscopy (MRS) . Reduced N-acetyl aspartate and choline-containing substances are significant neurometabolic alterations in alcohol-dependent patients . PET imaging has been used to investigate the DA system extensively. The most consistent findings in alcohol-dependent patients have been altered DA function with decreased DA transmission in the NAC and a decrease in DA D2 receptor density, which may be connected to the intensity of desire and relapse behavior. The development of NMDA receptor, in addition to metabotropic glutamate receptor PET ligands, as well as recent improvements in glutamate spectroscopy, will aid in applying this knowledge to alcohol-dependent individuals .   PHARMACODYNAMIC EFFECTS OF ALCOHOL AND TREATMENT ASPECTS Alcohol has complicated pharmacology, affecting different receptor or effector proteins through direct or indirect interactions, and at very high doses, it may even modify the lipid makeup of the surrounding membrane . The ability of several alcohols to suppress the NMDA-activated current is proportional to their intoxicating potency, implying that alcohol-induced suppression of responses to NMDA receptor activation may contribute to intoxication-related neurological and cognitive deficits. Alcohol enhances the action of 5-hydroxytryptamine 3 (serotonin) and neuronal nicotinic ACh receptor (nAChR) in addition to GABAA and glycine receptors . Alcohol also has a strong affinity for ion channels, and as a result, alcohol blocks dihydropyridine-sensitive L-type Ca 2+ channels . Recent molecular pharmacology studies show that alcohol has significantly less key targets, counting NMDA, GABAA, 5-HT3, nAChRs, and L-type Ca 2+ channels, despite the belief that it is an unspecific pharmacological agent . Activated G-protein inwardly rectifying K channels (GIRKs) , where concentrations as low as 1mM influence the activity of these receptors and ion channels. N-cholinergic agonists and 5-HT3 receptor agonists also enhance the alcohol stimulation effect. As a result, treatment has progressed from social and behavioral rehabilitation to complementary pharmacotherapies aimed at disrupting the underlying mechanisms. Pharmacological inhibition of opioid receptors resulted in a considerable reduction in high alcohol intake in an animal model displaying excessive alcohol consumption generated by such a post-dependent condition . Following their preclinical discovery of a genetic defect in the neurokinin 1 receptor  have a significant reduction in voluntary alcohol consumption. Neramexane  is a brand-new NMDA glutamate receptor antagonist with a moderate affinity and low competitiveness. It works by shutting down the NMDA receptor channel. Topiramate (Topamax), an anticonvulsant that inhibits glutamate activity  while facilitating GABA action, lowers the negative consequences of binge drinking and relapse rates in alcoholics. Ondansetron, a 5-HT3 antagonist , is another potential medicine for treating AUD. Galantamine  is an allosteric modulator of nACh receptors and a reversible, competitive inhibitor of acetylcholinesterase . In an operant self-administration drinking scenario, acute treatment of varenicline in dosages reported diminishing nicotine reinforcement lowered selectively desire for ethanol but not sucrose . There is an urgent need for novel pharmacotherapies, and alcohol-related diseases have been treated with medicines that target GABAB receptors . Additionally, a summary of laboratory studies looking at the biobehavioral effects of Baclofen, polymorphisms related to baclofen treatment, and safety issues with GABAB therapies will be covered. A possible treatment for AUD is Baclofen, a selective gamma-aminobutyric acid-B (GABA-B) receptor agonist. Since the early 1970s, it has been advertised for managing secondary neurological disorders' muscle stiffness. According to research that dates back to the 1970s and focused primarily on animal addiction models, Baclofen may also be helpful in treating AUD. Baclofen is one drug that targets GABAB receptors and may be moderately successful in treating alcohol consumption disorders. However, safety issues prevent the currently available drugs from being used widely . Baclofen therapy also reduced the frequency of daily alcoholic beverages and the obsessive and compulsive aspects of alcohol seeking. Finally, in alcohol-dependent patients, a single non-sedative dose of Baclofen caused the quick elimination of alcohol withdrawal symptoms, including delirium tremens. Baclofen was well tolerated in clinical testing with few adverse effects, which suggests that Baclofen may be a potentially helpful drug in the treatment of people with alcohol dependence . When consumed, Baclofen causes the brain's GABA receptors to become active. Baclofen can reduce the neuronal activity that causes muscular spasms because it inhibits these receptors. Phenibut, which is similar to Baclofen, also affects GABA receptors. G protein-coupled GABAB receptors are responsible for delayed and protracted inhibitory effects by activating G-i/o-type proteins. GABAB receptors slow down nerve impulses by turning on inwardly rectifying K+ channels, turning off voltage-gated Ca 2+ channels, and turning off adenylate cyclase.   NEUROPROTEOMIC MARKERS AND DIFFERENT PROTEIN EXPRESSIONS OF ALCOHOL USE DISORDER Alcohol addiction is one of the utmost paid health issues since it produces physiological changes in the brain and affects many areas. Alcohol not only affects memory and brain cells, but it also causes undesired and useful proteins to be expressed and suppressed, respectively. For studying different characteristics of brain components, particularly the proteome of brain cells, several methodologies involving separation techniques, quantification techniques, and analytical techniques, as well as a mix of bioinformatic tools, are used. These could be employed as alcoholic neuroproteomics indicators. Furthermore, neuroproteomics studies the impact of alcohol on the brain proteome using various animal models, preferably those that resemble humans . Different proteins including glyceraldehyde 3-phosphate dehydrogenase, syntaxin binding protein 1, dihydropyrimidinase-related protein 2, heat shock 70–71 kDa proteins, neurofilament light polypeptide, guanine nucleotide-binding protein, creatine kinase and septin have all been found to be differentially expressed in the human alcoholic frontal cortex. Early detection is critical for the successful treatment of most diseases. In the realm of alcohol, biomarkers with diagnostic and prognostic significance are essential. Most people with AUD or alcohol use disorders go undetected until they face serious medical, legal, or societal consequences. In addition, biomarkers for alcohol consumption (Fig. ) with broader evaluation ranges have been discovered. These biomarkers  detect tissue damage or different physiological reactions to heavy drinking over time and indirectly assess alcohol consumption . One of the best specific blood markers of chronic, heavy alcohol use is carbohydrate-deficient transferrin (CDT) . G-Glutamyltransferase (GGT) is another serum sign that is commonly examined. Since GGT is also elevated in non-alcohol-related liver disorders, it is less specific than CDT . EtG, or ethyl glucuronide, is a promising alcohol metabolite biomarker. So far, no clinical test has been found to be sufficiently trustworthy to support analysis of active AUD or abuse in the general populace . Addiction-related biomarkers might be useful in detecting addiction without the traditional social outcomes, as in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), and also regardless of whether patients have experienced tolerance or removal to an addictive agent; actually, some people may experience changes in other domains of brain function irrespective of physical patience or withdrawal .   Alcohol's main action is known to be mediated by the NMDA, GABAA, glycine, 5-HT3, and nAChR neurotransmitter/neuromodulator systems, L-type Ca 2+ channels and GIRKs. As soon as alcohol drinking is commenced, alcohol affects all brain neurotransmission essentially. However, some counter-adaptive alterations in the brain reinforcement system, such as modulatory input systems, may become chronic, and it is thought that these persistent modifications are what cause the 'molecular and structural flip' from controlled to compulsive alcohol misuse. Omics techniques have been widely employed to investigate altered gene/protein expression patterns in the brain due to excessive alcohol use. While the use of miRNAomic, transcriptomic, and proteomic approaches in the alcohol-based investigation has yielded a wealth of data, our knowledge of how personal expression changes interact to contribute to AUD remains restricted. Proteomic approaches have revolutionized how we evaluate the configuration, regulation, and function of protein complexes and pathways underpinning altered neurobiological circumstances dramatically in the last decade. These advancements, when paired with complementary techniques, provide the contextual knowledge needed to decode massive data sets into biologically significant adaptive processes. Dysregulation in molecular signalling transversely in numerous brain areas causes chronic alcohol addiction. Due to our limited understanding of the molecular pathways that impact addiction pathology, there are insufficient treatment choices for treating alcohol addiction and related psychiatric problems in clinical settings. Addiction-related behaviors originate from the convergence of multiple minor deviations in molecular signalling networks, including protein-protein interactions (interactome), neuropeptides (neuropeptidome), and post-translational modifications, counting protein phosphorylation, according to many studies (phosphoproteome). As our knowledge of the neuroscience of addiction has grown, it has become clear that slight alterations in discrete brain circuits can allow maladaptive temperament and cognition patterns, leading to relapse and long-term alcohol use. Neuroproteomics has the potential to revolutionize alcohol research by allowing researchers to gain a better knowledge of how alcohol impacts protein structure, function, connections, and networks on a global scale. These discoveries have yielded a plethora of information that can be used to find essential biomarkers for early detection and better prognosis of AUD, as well as prospective pharmacological targets for managing this addiction. The integration of addiction biomarkers into particular functional patterns across brain domains suggests that assessing these domains' weaknesses and strengths is a crucial initial step in assessing addictions. Improved neuroproteomics, in combination with new technology, will eventually aid in the development of preventive medications for those who have a genetic or behavioral predisposition to AUD, potentially paving the way for a breakthrough in addiction therapy. The identification of different profiles, when combined with genetic background, may be one way that neuroscience-based biomarkers may support elucidating the heterogeneity existing in an addictive disease, with the goal of targeting feebleness and strengths in any given individual and stirring towards precision medicine.   