Surbhi Gupta

Pharmacological benefits of agomelatine and vanillin in experimental model of Huntington's disease.

Huntingtons disease (HD), a devastating neurodegenerative disorder, is characterized by progressive motor dysfunction, emotional disturbances, dementia, weight loss, depression. Melatonin receptors are widely expressed in the central nervous system. Vanilloids are also valuable as pharmacological tools for investigating neurobiology. This study investigates the utility of agomelatine, a dual agonist of MT₁ and MT₂ melatonin receptor as well as vanillin, a selective agonist of TRPV₁ (vanilloid receptor) in 3-nitropropionic acid (3-NPA) induced experimental HD in rats. Locomotor activity (Actophotometer), motor coordination (Rota rod) and learning-memory (Morris water maze) were assessed. Brain striatum oxidative stress (lipid peroxidation-MDA, glutathione-GSH, superoxide dismutase-SOD and catalase-CAT), nitrosative stress (nitrite/nitrate) and mitochondrial enzyme complexes (I, II and IV) were also assessed. 3-NPA has induced weight loss, impaired locomotion, motor coordination as well as learning and memory. It has induced brain striatum oxidative as well as nitrosative stress, cholinergic dysfunction and impaired mitochondrial enzyme complexes (I, II and IV). Tetrabenazine (TBZ) was used as positive control. Treatment with agomelatine and vanillin and TBZ has significantly attenuated 3-NPA induced weight loss, impaired locomotion, motor coordination and learning-memory as well as biochemical impairments. Thus, agomelatine and vanillin exhibit protective effects against 3-NPA induced HD. It may be concluded that agomelatine and vanillin may provide benefits in HD.

Pharmacological modulation of I1-imidazoline and α2-adrenoceptors in sub acute brain ischemia induced vascular dementia

Sub-acute brain ischemia is a risk factor for the development of vascular dementia (VaD). Sub-acute brain ischemia induced VaD, participates in a negative role in impaired cognition. Imidazoline receptors are widely expressed in the central nervous system. But the role of I1-imidazoline and α2-adrenoceptors in VaD are still unknown. The present study has been designed to investigate the role of selective I1-imidazoline receptor modulator; moxonidine as well as α2-adrenoceptor modulator; clonidine in sub-acute brain ischemia induced VaD in mice (n=8). Permanent bilateral common carotid arteries ligation (2VO) technique was used to induce sub-acute brain ischemia in mice. Assessment of spatial learning and memory was done by using Morris water maze. Brain damage was assessed as percent infarct, using TTC staining of brain coronal sections. Oxidative stress was assessed by estimating brain malondialdehyde (MDA), catalase (CAT), glutathione (GSH) and superoxide dismutase (SOD). Cholinergic status was assessed by brain acetylcholinesterase (AChE) activity. 2VO animals have shown significant reduction in learning and memory as well as brain CAT, GSH and SOD, with significant increase in brain infarct size, MDA and AChE activity. Whereas, administration of moxonidine and clonidine significantly attenuated 2VO induced learning and memory deficits, brain damage, brain oxidative stress and higher AChE activity. It may be concluded that 2VO induced sub-acute brain ischemia has elicited dementia, which was attenuated by moxonidine and clonidine. Thus, modulators of I1-imidazoline receptors may be explored further for their benefits in sub-acute brain ischemia induced vascular dementia.

Protective effects of phosphodiesterase-1 (PDE1) and ATP sensitive potassium (KATP) channel modulators against 3-nitropropionic acid induced behavioral and biochemical toxicities in experimental Huntington׳s disease

Huntington׳s disease (HD), a devastating neurodegenerative disorder, is characterized by weight loss, impairment of motor function, cognitive dysfunction, neuropsychiatric disturbances and striatal damage. Phosphodiesterase-1 (PDE1) has been implicated in various neurological diseases. Mitochondrial potassium channels in the brain take part in neuroprotection. This study has been structured to investigate the role of vinpocetine, a selective PDE1 inhibitor as well as nicorandil, selective ATP sensitive potassium (KATP) channel opener in 3-nitropropionic acid (3-NP) induced HD symptoms in rats. Systemic administration of 3-NP significantly, reduced body weight, impaired locomotion, grip strength and impaired cognition. 3-NP elicited marked oxidative stress in the brain (enhanced malondialdehyde-MDA, reduced glutathione-GSH content, superoxide dismutase-SOD and catalase-CAT), elevated brain acetylcholinesterase activity and inflammation (myeloperoxidase-MPO), with marked nitrosative stress (nitrite/nitrate) in the brain. 3-NP has also induced mitochondrial dysfunction (impaired mitochondrial NADH dehydrogenase-complex I, succinate dehydrogenase-complex II and cytochrome oxidase-complex IV) activities in the striatum of the rat. Tetrabenazine was used as a positive control. Treatment with vinpocetine, nicorandil and tetrabenazine ameliorated 3-NP induced reduction in body weight, impaired locomotion, grip strength and impaired cognition. Treatment with these drugs reduced brain striatum oxidative (MDA, GSH, SOD and CAT) and nitrosative (nitrite/nitrate) stress, acetylcholinesterase activity, inflammation and mitochondrial dysfunctions. These results indicate that vinpocetine, a selective PDE1 inhibitor and nicorandil, a KATP channel opener have attenuated 3-NP induced experimental HD. Hence, pharmacological modulation of PDE1 as well as KATP channels may be considered as potential research targets for mitigation of HD.

Modulation of Transient Receptor Potential Vanilloid Subtype 1 (TRPV 1 ) and Norepinephrine Transporters (NET) Protect Against Oxidative Stress, Cellular Injury, and Vascular Dementia

Chronic cerebral hypoperfusion (CCH) is a risk factor for the development of vascular dementia (VaD). CCH participates in a negative role in cognitive impairments. Transient receptor potential vanilloid subtype 1 (TRPV1) participates in cognition, ischemic damage and neuroprotection. Selective norepinephrine transporter (NET) inhibitors have a role in cognitive dysfunction and oxidative stress. The role of TRPV1 and NET in CCH induced VaD is still unknown. The present study has been structured to investigate the role of vanillin; a selective agonist of TRPV1 as well as atomoxetine; a selective NET inhibitor in CCH induced VaD in mice. Permanent bilateral common carotid arteries ligation or two vessel occlusion (2VO) technique was used to induce a stage of chronic cerebral hypoperfusion in mice. 2VO animals have shown significant impairment of locomotion (Actophotometer), motor coordination (Rota rod), learning and memory (Morris water maze). 2VO animals have shown significant reduction in brain catalase, glutathione, and superoxide dismutase, with significant increase in brain infarct size (TTC staining), malondialdehyde and acetyl cholinesterase-AChE activity. Whereas, administration of vanillin as well as atomoxetine has significantly attenuated 2VO induced impaired locomotion, motor coordination, learning and memory, brain damage, brain oxidative stress and higher AChE activity. It may be concluded that 2VO induced CCH has elicited VaD, which was attenuated by vanillin and atomoxetine. Thus, modulators of vanilloid receptors and norepinephrine transporter may be explored further for their benefits in CCH induced VaD.

Pharmacological benefit of I1-imidazoline receptors activation and nuclear factor kappa-B (NF-κB) modulation in experimental Huntington's disease

Huntingtons disease (HD), a neurodegenerative disorder, is characterized by progressive motor dysfunction, emotional disturbances, dementia, weight loss and anxiety. The tremendous amount of research work is required to identify new pharmacological agents of therapeutic utility to combat this condition. This study investigates the effect of selective modulator of I1-imidazoline receptor (moxonidine) as well as nuclear factor kappa-B (NF-κB) (natrium diethyl dithio carbamate trihydrate-NDDCT) on 3-nitropropionic acid (3-NPA) induced experimental HD condition. 3-NPA was used to induce mitochondrial damage and associated HD symptoms in rats. Anxiety was assessed using Elevated plus maze-EPM and learning-memory was assessed using EPM and Morris water maze-MWM. Different biochemical estimations were used to assess brain striatum oxidative stress (lipid peroxide, superoxide dismutase and catalase), nitric oxide levels (nitrite/nitrate), cholinergic activity (brain striatum acetyl cholinesterase activity), and mitochondrial enzyme complex (I, II and IV) activities. 3-NPA has induced anxiety, impaired learning-memory with a reduction in body weight, locomotor activity, grip strength. It has increased brain striatum acetylcholinesterase-AChE activity, oxidative stress (lipid peroxide, nitrite/nitrate, superoxide dismutase and catalase) and impaired mitochondrial complex enzyme (I, II and IV) activities. Tetrabenazine-TBZ (monoamine storage inhibitor) was used as positive control. Treatment with moxonidine, NDDCT and TBZ significantly attenuated 3-NPA induced reduction in body weight, locomotor activity, grip strength, anxiety as well as impaired learning and memory. Administration of these agents attenuated 3-NPA induced various biochemical impairments. Therefore, modulation of I1-imidazoline receptor as well as NF-κB may be considered as potential pharmacological agents for the management of 3-NPA induced HD.

Melatonin receptor and KATP channel modulation in experimental vascular dementia.

Cerebrovascular and cardiovascular diseases are stated as important risk factors of vascular dementia (VaD) and other cognitive disorders. In the central nervous system, melatonin (MT1/MT2) as well as serotonin subtype 2C (5-HT2C) receptors is pharmacologically associated with various neurological disorders. Brain mitochondrial potassium channels have been reported for their role in neuroprotection. This study has been structured to investigate the role of agomelatine, a melatonergic MT1/MT2 agonist and nicorandil, a selective ATP sensitive potassium (KATP) channel opener in renal artery ligation (two-kidney-one-clip: 2K1C) hypertension induced endothelial dysfunction, brain damage and VaD. 2K1C-renovascular hypertension has increased mean arterial blood pressure (MABP), impaired memory (elevated plus maze and Morris water maze), endothelial function, reduced serum nitrite/nitrate and increased brain damage (TTC staining of brain sections). Furthermore, 2K1C animals have shown high levels of oxidative stress in serum (increased thiobarbituric acid reactive species-TBARS with decreased levels of glutathione-GSH, superoxide dismutase-SOD and catalase-CAT), in the aorta (increased aortic superoxide anion) and in the brain (increased TBARS with decreased GSH, SOD and CAT). 2K1C has also induced a significant increase in brain inflammation (myeloperoxidase-MPO levels), acetylcholinesterase activity (AChE) and calcium levels. Impairment in mitochondrial complexes like NADH dehydrogenase (complex-I), succinate dehydrogenase (complex-II) and cytochrome oxidase (complex-IV) was also noted in 2K1C animals. Administration of agomelatine, nicorandil and donepezil significantly attenuated 2K1C-hypertension induced impairments in memory, endothelial function, nitrosative stress, mitochondrial dysfunction, inflammation and brain damage. Therefore, modulators of MT1/MT2 receptors and KATP channels may be considered as potential agents for the management of renovascular hypertension induced VaD.

In vivo and in vitro attenuation of naloxone-precipitated experimental opioid withdrawal syndrome by insulin and selective KATP channel modulator

RationaleOpiate exposure for longer duration develops state of dependence in humans and animals, which is revealed by signs and symptoms of withdrawal precipitated by opioid receptor antagonists. The sudden withdrawal of opioids produces a withdrawal syndrome in opioid-dependent subjects. Insulin and ATP-sensitive potassium (KATP) channel-mediated glucose homeostasis have been shown to modulate morphine withdrawal.ObjectivePresent study has been structured to investigate the role of insulin and pharmacological modulator of KATP channel (gliclazide) in experimental morphine withdrawal syndrome, both invivo and invitro.MethodsIn this study, naloxone-precipitated morphine withdrawal syndrome in mice (invivo) as well as in rat ileum (invitro) were utilized to assess opioid withdrawal phenomenon. Morphine withdrawal syndromes like jumping and rearing frequency, forepaw licking, circling, fore paw tremor, wet dog shake, sneezing, overall morphine withdrawal severity (OMWS), serum glucose, brain malondialdehyde (MDA), glutathione (GSH), nitrite/nitrate, and calcium (Ca+2) were assessed.ResultsNaloxone has significantly increased morphine withdrawal syndrome, both invivo and invitro. Insulin and gliclazide have significantly attenuated, naloxone induced behavioral changes like jumping and rearing frequency, forepaw licking, wet dog shake, sneezing, straightening, circling, OMWS, and various biochemical impairments such as serum glucose, brain MDA, GSH, nitrite/nitrate, and Ca+2 in morphine-dependent animals (invivo). In vitro, insulin and gliclazide have significantly reduced naloxone-induced contraction in morphine-withdrawn rat ileum preparation.ConclusionsInsulin and gliclazide (KATP channel blocker) have attenuated naloxone-precipitated morphine withdrawal syndrome, both invivo and invitro. Thus, insulin and KATP channel modulation may provide new avenues for research in morphine withdrawal.

Antagonism of Endothelin (ETA and ETB) Receptors During Renovascular Hypertension-Induced Vascular Dementia Improves Cognition

BACKGROUND Diseases of cardio, as well as the cerebrovascular system, are known as the primary possibility for deficits in cognitive processes and dementia of vascular nature. Endothelin-1 (ET-1) and its receptors are extensively expressed in brain. OBJECTIVE The present study has been structured to explore the effects of bosentan, an ET-1 antagonist on two-kidneyone- clip: 2K1C method induced hypertension provoked vascular dementia (VaD). METHOD 2K1C was modelled to induce renovascular hypertension. Mean arterial blood pressure (MABP) was assessed using BIOPAC system. Cognitive impairment was assessed employing Elevated plus maze-EPM as well as Morris water maze-MWM. Brain cholinergic dysfunction (activity of acetylcholinesterase-AChE), oxidative stress (thiobarbituric acid reactive substances-TBARS level, glutathione-GSH content, superoxide dismutase-SOD as well as catalase-CAT activity), aortic oxidative stress (superoxide anion level), serum nitrosative stress (nitrite/nitrate level), brain inflammation (myeloperoxidase-MPO), vascular endothelial dysfunction (endothelium-dependent relaxation) and infarct size (2,3,5- triphenyltetrazolium chloride-TTC staining) were assessed. RESULTS Renal artery ligated animals have shown elevated oxidative stress in the aorta (superoxide anion-SA) and brain (augmented TBARS, with decreased GSH, SOD, and CAT). Similarly, 2K1C-renovascular hypertension has shown a considerable rise in brain inflammation (MPO activity) and brain AChE activity with a significant fall in serum nitrite/ nitrate contents. Administration of bosentan considerably diminished 2K1C hypertension induced alterations in MABP, cognitive impairment, and dysfunction of endothelium. Treatment with bosentan has also restored 2K1C induced a rise in brain TBARS, AChE, MPO activity, reduction in brain GSH, SOD and CAT as well as brain damage. CONCLUSION It may be concluded that ET-1 antagonism may be regarded as possible agents for managing renovascular hypertension induced VaD.