Protective effects of Embelin in Benzo[α]pyrene induced cognitive and memory impairment in experimental model of mice.

Alzheimer's disease (AD) is a neurodegenerative disease that affects the neurons in the hippocampus, resulting in cognitive and memory impairment. The most prominent clinical characteristics of AD are the production of amyloid-beta (Aß) plaques, neurofibrillary tangles, and neuroinflammation in neurons. It has been proven that embelin (Emb) possesses antioxidant, anti-inflammatory, and neuroprotective properties. Therefore, we assessed the therapeutic potential of Emb in Benzo [α]pyrene (BaP)-induced cognitive impairment in experimental mice. BaP (5 mg/kg, i. p) was given to mice daily for 28 days, and Emb (2.5, 5, and 10 mg/kg, i. p) was given from 14 to 28 days of a protocol. In addition, locomotor activity was evaluated using open-field and spatial working, and non-spatial memory was evaluated using novel object recognition tasks (NORT), Morris water maze (MWM), and Y- maze. At the end of the study, the animal tissue homogenate was used to check biochemicals, neuroinflammation, and neurotransmitter changes. BaP-treated mice showed a significant decline in locomotor activity, learning and memory deficits and augmented oxidative stress (lipid peroxidation, nitrite, and GSH). Further, BaP promoted the release of inflammatory tissue markers, decreased acetylcholine, dopamine, GABA, serotonin, and norepinephrine, and increased glutamate concentration. However, treatment with Emb at dose-dependently prevented biochemical changes, improved antioxidant levels, reduced neuroinflammation, restored neurotransmitter concentration, and inhibited the NF-κB pathway. The current study's finding suggested that Emb improved cognitive functions through antioxidant, anti-inflammatory, and neuroprotective mechanisms and inhibition of acetylcholinesterase (AChE) enzyme activities and Aß-42 accumulation.

L-theanine attenuates LPS-induced motor deficit in experimental rat model of Parkinson's disease: emphasis on mitochondrial activity, neuroinflammation, and neurotransmitters.

RATIONALE: Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of dopaminergic neurons. The pathogenesis of PD includes oxidative stress, mitochondrial dysfunction, neuroinflammation, and neurotransmitter dysregulation. L-theanine is found in green tea and has antioxidant, anti-inflammatory, and neuroprotective effects with a high blood brain barrier permeability. OBJECTIVE: The objective of this study was to investigate the possible neuroprotective effect of L-theanine in lipopolysaccharide (LPS) induced motor deficits and striatal neurotoxicity in a rat model of PD. METHODS: LPS was infused at a dose of 5 µg/5 µl PBS stereotaxically into SNpc of rats. Treatment with L-theanine (50 and 100 mg/kg; po) and Sinemet (36 mg/kg; po) was given from day 7 to 21 in of LPS injected rat. On a weekly basis all behavioral parameters were assessed, and animals were sacrificed on day 22. The striatum tissue of brain was isolated for biochemicals (Nitrite, GSH, catalase, SOD, mitochondrial complexes I and IV), neuroinflammatory markers, and neurotransmitters (serotonin, dopamine, norepinephrine, GABA, and glutamate) estimations. RESULTS: Results revealed that L-theanine dose-dependently and significantly reversed motor deficits, assessed through locomotor and rotarod activity. Moreover, L-theanine attenuated biochemical markers, reduced oxidative stress, and neurotransmitters dysbalance in the brain. L-theanine treatment at 100 mg/kg; po substantially reduced these pathogenic events by increasing mitochondrial activity, restoring neurotransmitter levels, and inhibiting neuroinflammation. CONCLUSIONS: These data suggest that the positive effects of L-theanine on motor coordination may be mediated by the suppression of NF-κB induced by LPS. Therefore, L-theanine would have a new therapeutic potential for PD.

Microbiota- Brain-Gut-Axis Relevance to Parkinson's Disease: Potential Therapeutic Effects of Probiotics.

Parkinson's disease (PD) is the second most common type of neurogenerative disease among middleaged and older people, characterized by aggregation of alpha-synuclein and dopaminergic neuron loss. The microbiota- gut-brain axis is a dynamic bidirectional communication network and is involved in the pathogenesis of PD. The aggregation of misfolded protein alpha-synuclein is a neuropathological characteristic of PD, originates in the gut and migrates to the central nervous system (CNS) through the vagus nerve and olfactory bulb. The change in the architecture of gut microbiota increases the level short-chain fatty acids (SCFAs) and other metabolites, acting on the neuroendocrine system and modulating the concentrations of gamma-Aminobutyric acid (GABA), serotonin, and other neurotransmitters. It also alters the vagus and intestinal signalling, influencing the brain and behaviour by activating microglia and systemic cytokines. Both experimental and clinical reports indicate the role of intestinal dysbiosis and microbiota host interaction in neurodegeneration. Probiotics are live microorganisms that modify the gut microbiota in the small intestine to avoid neurological diseases. Probiotics have been shown in clinical and preclinical studies to be effective in the treatment of PD by balancing the gut microbiota. In this article, we described the role of gut-microbiota in the pathogenesis of PD. The article aims to explore the mechanistic strategy of the gut-brain axis and its relation with motor impairment and the use of probiotics to maintain gut microbial flora and prevent PD-like symptoms.

Design, Synthesis, and Pharmacological Evaluation of N-Propargylated Diphenylpyrimidines as Multitarget Directed Ligands for the Treatment of Alzheimer's Disease.

Alzheimer's disease (AD), a multifactorial complex neural disorder, is categorized with progressive memory loss and cognitive impairment as main clinical features. The multitarget directed ligand (MTDL) strategy is explored for the treatment of multifactorial diseases such as cancer and AD. Herein, we report the synthesis and screening of 24 N-propargyl-substituted diphenylpyrimidine derivatives as MTDLs against acetylcholine/butyrylcholine esterases and monoamine oxidase enzymes. In this series, VP1 showed the most potent MAO-B inhibitory activity with an IC50 value of 0.04 ± 0.002 µM. VP15 with an IC50 value of 0.04 ± 0.003 µM and a selectivity index of 626 (over BuChE) displayed the most potent AChE inhibitory activity in this series. In the reactive oxygen species (ROS) inhibition studies, VP1 reduced intercellular ROS levels in SH-SY5Y cells by 36%. This series of compounds also exhibited potent neuroprotective potential against 6-hydroxydopamine-induced neuronal damage in SH-SY5Y cells with up to 90% recovery. In the in vivo studies in the rats, the hydrochloride salt of VP15 was orally administered and found to cross the blood-brain barrier and reach the target site. VP15·HCl significantly attenuated the spatial memory impairment and improved the cognitive deficits in the mice. This series of compounds were found to be irreversible inhibitors and showed no cytotoxicity against neuronal cells. In in silico studies, the compounds attained thermodynamically stable orientation with complete occupancy at the active site of the receptors. Thus, N-propargyl-substituted diphenylpyrimidines displayed drug-like characteristics and have the potential to be developed as MTDLs for the effective treatment of AD.

Protective effects of cerebrolysin against chemotherapy (carmustine) induced cognitive impairment in Albino mice.

Chemotherapy-induced cognitive impairment (CICI) comprises different neurological problems, including difficulty in learning new things, concentrating and making decisions that affect daily life activities. Clinical reports indicate that around 70% of cancer patients receiving chemotherapy suffer from cognitive impairment. The purpose of the present study is to examine the effects of widely used anticancer medication (Carmustine) on cognitive function using mice model and investigation of the neuroprotective effects of Cerebrolysin (CBN). Cerebrolysin (CBN) is a mixture of several neurotrophic factors and active peptides with anti-inflammatory, antioxidant, and neuroprotective actions. Our study aimed to establish a mice model of Carmustine (BCNU)-induced cognitive deficits and determine the protective effects of CBN. BCNU (10 mg/kg, i.v.) was administered to mice for 28 days, and behavioral parameters were measured on a weekly basis. CBN (44 and 88 mg/kg, i.p.) was administered daily from day 1 to 28 to BCNU treatment mice. All animals were sacrificed on day 29 and brain hippocampus tissues were used for biochemical, neuroinflammatory, neurotransmitters analysis. BCNU administration animals showed impaired cognition and memory, confirmed from behavioral analysis. Further, BCNU increased oxidative stress, inflammatory cytokines release and altered neurotransmitters concentration as compared to the control group (p < 0.01). However, mice treated with CBN (44 and 88 mg/kg, i.p.) significantly and dose-dependently improved cognitive functions, reduced oxidative stress markers, inflammatory cytokines and restored neurotransmitters concentration as compared to BCNU administered mice (p < 0.05). The finding of current study suggested that CBN could be the promising compound to reverse cognitive impairment associated with use of chemotherapy.

l-Theanine ameliorates motor deficit, mitochondrial dysfunction, and neurodegeneration against chronic tramadol induced rats model of Parkinson's disease.

Parkinson's disease (PD) is the second most prevalent progressive neurodegenerative disease, characterized by loss of dopaminergic neurons in substantia nigra, with deficiency of dopamine in the striatum. Tramadol is safe analgesic but long-term use confirmed to elevate oxidative stress, neuroinflammation, mitochondrial dysfunction, in brain leads to motor deficits. l-Theanine is an active constituent of green tea which prevents neuronal loss, mitochondrial failure and improves dopamine, gamma-aminobutyric acid (GABA), serotonin levels and in the central nervous system (CNS) via antioxidant, anti-inflammatory, and neuromodulatory properties. In the present study, tramadol was injected intraperitoneally to Wister rats for 28 days at a dose of 50 mg/kg. l-Theanine (25, 50, and 100 mg/kg) was administered orally 3 h before tramadol administration from day 14 to day 28. Behavioral analyses including rotarod, narrow beam walk, open field, and grip strength were used to evaluate motor coordination on a weekly basis. On the day 29, all Wistar rats were sacrificed and striatum homogenates were used for biochemical (lipid peroxidation, nitrite, glutathione, glutathione peroxidase activity, superoxide dismutase, catalase, mitochondrial complex I, IV, and cyclic adenosine monophosphate), neuroinflammatory markers (tumor necrosis factor-α, interleukin-1ß, and interleukin-17), and neurotransmitters (dopamine, norepinephrine, serotonin, GABA, and glutamate) analysis. Chronic tramadol treatment caused motor deficits reduced antioxidant enzymes level, increased striatal proinflammatory cytokines release, dysbalanced neurotransmitters, and reduced mitochondrial complex activity I, IV, and cAMP activity. However, l-theanine administration attenuated behavioral, biochemical, neuroinflammatory, neurotransmitters, and mitochondrial activity indicated it as a promising neuroprotective potential against degenerative changes in experimental model of PD.

Neuroprotective Effect of Fucoxanthin against Intracerebroventricular Streptozotocin (ICV-STZ) Induced Cognitive Impairment in Experimental Rats.

BACKGROUND: Alzheimer's disease (AD) is a neurological disorder characterized by loss of memory and cognitive functions caused by oxidative stress, neuroinflammation, change in neurotransmitter levels, and excessive deposition of Aß(1-42) plaques. Fucoxanthin is a carotenoid with potential antioxidant, anti-inflammatory, and neuroprotective actions. OBJECTIVE: In the present study, fucoxanthin was employed as a protective strategy in Intracerebroventricular Streptozotocin (ICV-STZ) induced experimental model of cognitive impairment. METHODS: STZ was injected twice ICV (3 mg/kg) on alternate days 1 and 3, and Wistar rats were evaluated for the memory analysis using Morris water maze and elevated plus-maze. Fucoxanthin at low 50 mg/kg, p.o. and high dose 100 mg/kg, p.o. was administered for 14 days. All animals were sacrificed on day 29, and brain hippocampus tissue after isolation was used for biochemical (MDA, nitrite, GSH, SOD and Catalase), neuroinflammatory (TNF-α, IL-1ß, and IL-6), neurotransmitters (ACh, GABA Glutamate), Aß(1-42) and Tau protein measurements. RESULTS: STZ-infused rats showed significant impairment in learning and memory, increased oxidative stress (MDA, nitrite), reduced antioxidant defense (GSH, SOD and Catalase), promoted cytokine release, and change in neurotransmitters level. However, fucoxanthin improved cognitive functions, restored antioxidant levels, reduced inflammatory markers dose-dependently, and restored neurotransmitters concentration. CONCLUSION: The finding of the current study suggests that fucoxanthin could be the promising compound for improving cognitive functions through antioxidant, anti-inflammatory, and neuroprotective mechanisms, and inhibition of acetylcholinesterase (AChE) enzyme activities, Aß(1-42) accumulation, and tau protein.

Spermine protects aluminium chloride and iron-induced neurotoxicity in rat model of Alzheimer's disease via attenuation of tau phosphorylation, Amyloid-ß (1-42) and NF-κB pathway.

Alzheimer's disease (AD) is the most prevalent type of dementia, characterized by a gradual decline in cognitive and memory functions of the aged peoples. Long-term exposure to heavy metals (aluminium and iron) cause neurotoxicity by amyloid plaques accumulation, tau phosphorylation, increased oxidative stress, neuroinflammation, and cholinergic neurons degeneration, contributes to the development of AD-like symptoms. The present research work is designed to investigate the neuroprotective effect of spermine in aluminium chloride (AlCl3), and iron (Fe) induced AD-like symptoms in rats. Rats were administered of AlCl3 (100 mg/kg p.o.) alone and in combination with iron (120 µg/g, p.o.) for 28 days. Spermine (5 and 10 mg/kg) through intraperitoneal (i.p.) route was given for 14 days. The recognition and spatial memory impairment were tasted using Morris water maze (MWM), actophotometer, and Novel Object Recognition test (NORT). All the rats were sacrificed on day 29, brains were isolated, and tissue homogenate was used for neuroinflammatory, biochemical, neurotransmitters, metals concentration, and nuclear factor-kappa B (NF-κB) analysis. In the present study, AlCl3 and iron administration elevated oxidative stress, cytokines release, dysbalanced neurotransmitters concentration, and biochemical changes. Rats treated with spermine dose-dependently improved the recognition and spatial memory, attenuated proinflammatory cytokine release, and restored neurotransmitters concentration and antioxidant enzymes. Spermine also mitigated the increased beta-amyloid (Aß42), with downregulation of tau phosphorylation. Furthermore, spermine augmented the hippocampal levels of B cell leukaemia/lymphoma-2 (Bcl-2), diminished nuclear factor-kappa B (NF-κB) and caspase-3 (casp-3) expression. Moreover, spermine exhibited the neuroprotective effect through anti-inflammatory, antioxidant, neurotransmitters restoration, anti-apoptotic Aß42 concentration.

Allicin ameliorates aluminium- and copper-induced cognitive dysfunction in Wistar rats: relevance to neuro-inflammation, neurotransmitters and Aß(1-42) analysis.

Alzheimer's disease (AD) is a multifactorial neurological disorder associated with neuropathological and neurobehavioral changes, like cognition and memory loss. Pathological hallmarks of AD comprise oxidative stress, formation of insoluble ß-amyloid (Aß) plaques, intracellular neurofibrillary tangles constituted by hyperphosphorylated tau protein (P-tau), neurotransmitters dysbalanced (DA, NE, 5-HT, GABA and Glutamate) and metal deposition. Chronic exposure to metals like aluminium and copper causes accumulation of Aß plaques, promotes oxidative stress, neuro-inflammation, and degeneration of cholinergic neurons results in AD-like symptoms. In the present study, rats were administered with aluminium chloride (200 mg/kg p.o) and copper sulfate (0.5 mg/kg p.o) alone and in combination for 28 days. Allicin (10 and 20 mg/kg i.p) was administered from day 7 to day 28. Spatial and recognition memory impairment analysis was performed using Morris water maze, Probe trial, and Novel Object Recognition test. Animals were sacrificed on day 29, brain tissue was isolated, and its homogenate was used for biochemical (lipid peroxidation, nitrite, and glutathione), neuro-inflammatory (IL-1ß, IL-6 and TNF- α), neurotransmitters (DA, NE, 5-HT, GABA and Glutamate), Aß(1-42) level, Al concentration estimation, and Na+/K+-ATPase activity. In the present study, aluminium chloride and copper sulfate administration increased oxidative stress, inflammatory cytokines release, imbalanced neurotransmitters' concentration, and promoted ß-amyloid accumulation and Na+/K+-ATPase activity. Treatment with allicin dose-dependently attenuated these pathological events via restoration of antioxidants, neurotransmitters concentration, and inhibiting cytokine release and ß-amyloid accumulation. Moreover, allicin exhibited the neuroprotective effect through antioxidant, anti-inflammatory, neurotransmitters restoration, attenuation of neuro-inflammation and ß-amyloid-induced neurotoxicity.

Current understanding on molecular drug targets and emerging treatment strategy for novel coronavirus-19.

SARS-CoV-2 is an enveloped positive-sense RNA virus, contain crown-like spikes on its surface, exceptional of large RNA genome, and a special replication machinery. Common symptoms of SARS-CoV-2 include cough, common cold, fever, sore throat, and a variety of severe acute respiratory disease (SARD) such as pneumonia. SARS-CoV-2 infects epithelial cells, T-cells, macrophages, and dendritic cells and also influences the production and implantation of pro-inflammatory cytokines and chemokines. Repurposing of various drugs during this emergency condition can reduce the rate of mortality as well as time and cost. Two druggable protein and enzyme targets have been selected in this review article due to their crucial role in the viral life cycle. The eukaryotic translation initiation factor (eIF4A), cyclophilin, nucleocapsid protein, spike protein, Angiotensin-converting enzyme 2 (ACE2), 3-chymotrypsin-like cysteine protease (3CLpro), and RNA-dependent RNA polymerase (RdRp) play significant role in early and late phase of SARS-CoV-2 replication and translation. This review paper is based on the rationale of inhibiting of various SARS-CoV-2 proteins and enzymes as novel therapeutic approaches for the management and treatment of patients with SARS-CoV-2 infection. We also discussed the structural and functional relationship of different proteins and enzymes to develop therapeutic approaches for novel coronavirus SARS-CoV-2.

Metals associated neurodegeneration in Parkinson's disease: Insight to physiological, pathological mechanisms and management.

Parkinson's disease (PD) is a deliberately progressive neurological disorder, arises due to degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). The loss of dopaminergic nerves and dopamine deficiency leads to motor symptoms characterized by rigidity, tremor, and bradykinesia. Heavy metals and trace elements play various physiological and pathological roles in the nervous system. Excessive exposure to toxic metals like mercury (Hg), lead (Pb), copper (Cu), zinc (Zn), iron (Fe), manganese (Mn), aluminium (Al), arsenic (As), cadmium(cd), and selenium (Se) cross the blood-brain barrier to enter into the brain and leads to dopaminergic neuronal degeneration. Excessive concentrations of heavy metals in the brain promote oxidative stress, mitochondrial dysfunction, and the formation of α-synuclein leads to dopaminergic neuronal damage. There is increasing evidence that heavy metals normally present in the human body in minute concentration also cause accumulation to initiate the free radical formation and affecting the basal ganglia signaling. In this review, we explored how these metals affect brain physiology and their roles in the accumulation of toxic proteins (α-synuclein and Lewy bodies). We have also discussed the metals associated with neurotoxic effects and their prevention as management of PD. Our goal is to increase the awareness of metals as players in the onset and progression of PD.

Coronavirus as silent killer: recent advancement to pathogenesis, therapeutic strategy and future perspectives.

The present outbreak associated with corona virus [CoVs] in China which is believed to be one of the massive eruptions towards mankind in 2019-2020. In the present scenario CoVs has been transmitted to the European and American regions through the travellers from wide spread countries like China and Japan. The viral disease is spreading through the contact in any form by the infected persons or patients and creating huge risk of mortality. CoVs are a single positive-sense RNA virus; mutation rates are higher than DNA viruses and indicate a more effective survival adaption mechanism. Human CoVs can cause common cold and influenza-like illness and a variety of severe acute respiratory disease such as pneumonia. Early in infection, CoVs infects epithelial cells, macrophages, T-cells, dendritic cells and also can affect the development and implantation of pro-inflammatory cytokines and chemokines. It mainly produces the melanoma differentiation associated with protein-5, retinoic acid inducible gene-1 and endosomal toll-like receptor 3. How CoVs affects the function of the immune system is still unclear due to lack of this knowledge. No Food and Drug Administration approved treatment is available till date. In this review, we are tried to explore the epidemiology, pathogenesis and current treatment of CoVs infection. The promising therapeutics molecules against CoVs and future prospective have been also discussed which will be helpful for researchers to find out the new molecules for the treatment of CoVs disease.

Oxiracetam and Zinc Ameliorates Autism-Like Symptoms in Propionic Acid Model of Rats.

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by restrictive behaviour, deficit in social skills and interaction. The multifactorial etiology, complex pathophysiology and different combination of symptoms (unusual speech patterns, frequent repetition of phrases) make it difficult to treat. Thus, present study aimed to find the protective effects of oxiracetam alone and in combination with zinc on brain behavioral, biochemical, pro-inflammatory cytokines and neurotransmitters level. Rats were administered with propionic acid (250 mg/kg p.o.) for 3 days and immediately on next day treatment were given with oxiracetam (25, 50 mg/kg i.p), zinc (4 mg/kg) as well as oxiracetam (25 mg/kg i.p) in combination with zinc (4 mg/kg p.o). Behavioral parameters were performed from 22th to 28th day. On 29th day, all the animals were sacrificed by cervical dislocation and the brain was preserved for biochemical (LPO, GSH, nitrite, mitochondrial complex I, IV and cAMP), neuroinflammatory (TNF-α, IL-1ß, IL-6) and neurotransmitters (5-HT, GABA, glutamate and acetylcholine) analysis. The propionic acid administration showed memory impairment, restrictive behavior, increased proinflammatory cytokines level, biochemical and neurotransmitters alteration. However, treatment with oxiracetam alone and in combination with zinc significantly attenuated behavioral, biochemical, inflammatory cytokines and restored neurotransmitters level. The finding of present study demonstrated that oxiracetam alone and in combination with zinc afforded superior anti-autistic effect through antioxidant, anti-inflammatory and anti-excitotoxic mechanisms and could serve as attractive strategy in managing autism.

Neuroprotective Effect of Quercetin in Combination with Piperine Against Rotenone- and Iron Supplement-Induced Parkinson's Disease in Experimental Rats.

Parkinson's disease (PD) is a neurodegenerative disorder caused by selective dopaminergic neuronal loss. Rotenone is a neurotoxin that selectively destroys dopaminergic neurons, leading to PD-like symptoms. Quercetin possesses antioxidant, anti-inflammatory, and neuroprotective properties but a major drawback is its low bioavailability. Therefore, the present study was designed to evaluate the neuroprotective effect of quercetin in combination with piperine against rotenone- and iron supplement-induced model of PD. Rotenone was administered at a dose of 1.5 mg/kg through an intraperitoneal route with iron supplement at a dose of 120 µg/g in diet from day 1 to day 28. Pre-treatment with quercetin (25 and 50 mg/kg, p.o.), piperine (2.5 mg/kg, p.o.) alone, quercetin (25 mg/kg, p.o.) in combination with piperine (2.5 mg/kg), and ropinirole (0.5 mg/kg, i.p.) was administered for 28 days 1 h prior to rotenone and iron supplement administration. All behavioral parameters were assessed on weekly basis. On the 29th day, all animals were sacrificed and striatum was isolated for biochemical (LPO, nitrite, GSH, mitochondrial complexes I and IV), neuroinflammatory (TNF-α, IL-1ß, and IL-6), and neurotransmitter (dopamine, norepinephrine, serotonin, GABA, glutamate) estimation. Quercetin treatment attenuated rotenone- and iron supplement-induced motor deficits and biochemical and neurotransmitter alterations in experimental rats. However, combination of quercetin (25 mg/kg) with piperine (2.5 mg/kg) significantly enhanced its neuroprotective effect as compared with treatment with quercetin alone. The study concluded that combination of quercetin with piperine contributed to superior antioxidant, anti-inflammatory, and neuroprotective effect against rotenone- and iron supplement-induced PD in experimental rats.

Neurobehavioral Consequences Associated with Long Term Tramadol Utilization and Pathological Mechanisms.

Tramadol is a synthetic analog of codeine used to treat pain of moderate to severe intensity and is reported to have neurotoxic potential. At therapeutic dose, tramadol does not cause major side effects in comparison to other opioid analgesics, and is useful for the management of neurological problems like anxiety and depression. Long term utilization of tramadol is associated with various neurological disorders like seizures, serotonin syndrome, Alzheimer's disease and Parkinson's disease. Tramadol produces seizures through inhibition of nitric oxide, serotonin reuptake and inhibitory effects on GABA receptors. Extensive tramadol intake alters redox balance through elevating lipid peroxidation and free radical leading to neurotoxicity and produces neurobehavioral deficits. During Alzheimer's disease progression, low level of intracellular signalling molecules like cGMP, cAMP, PKC and PKA affect both learning and memory. Pharmacologically tramadol produces actions similar to Selective Serotonin Reuptake Inhibitors (SSRIs), increasing the concentration of serotonin, which causes serotonin syndrome. In addition, tramadol also inhibits GABAA receptors in the CNS has been evidenced to interfere with dopamine synthesis and release, responsible for motor symptoms. The reduced level of dopamine may produce bradykinesia and tremors which are chief motor abnormalities in Parkinson's Disease (PD).

Mitochondrial dysfunctioning and neuroinflammation: Recent highlights on the possible mechanisms involved in Traumatic Brain Injury.

Traumatic brain injury (TBI) is the injury to the vasculature of brain while trauma caused by physical, chemical and biological stimuli. TBI is the leading cause of mortality and morbidity around the world. In this, primary insult leads to secondary injury through the involvement and initiation of various pathological processes. The most citable includes excitotoxicity, Blood Brain Barrier (BBB) dysfunction, inflammation, mitochondrial dysfunction, oxidative stress, calcium efflux, microglial mediated release of proinflammatory mediators (cytokine, chemokines, interleukin, tissue necrosis factor etc.). The morphological changes in TBI are proportional to mitochondrial dysfunctioning and microglial activation, which play an assorted role in neurodegeneration following traumatic brain injury. It is also assumed that the release of nitric oxide, activation of microglial cells plays a diversive role in maintaining the physiological and pathological balance. This review cites different pathophysiological mechanisms that are involved in progenesis of secondary injury after primary insult. These targets further are useful to explore the deep molecular mechanisms and to analyse the effectiveness of available drugs. Moreover, the present review reflects the underlying inflammatory cascade responsible for neuronal loss and neurological deficit in TBI.