Effect of U50488, a selective kappa opioid receptor agonist and levetiracetam against lithium-pilocarpine-induced status epilepticus, spontaneous convulsive seizures and related cognitive impairment

PURPOSE

Kappa opioid receptor (KOR) agonists have anticonvulsant effect but their antiepileptogenic effect is unknown. U50488, a selective KOR agonist is used to determine its effect on status epilepticus (SE), spontaneous convulsive seizures (SS) and cognitive impairment in rat lithium-pilocarpine SE model. Effect of an antiepileptic drug levetiracetam is also studied.

METHOD

Male Wistar rats with SE were divided into three groups namely, LiP, LiP + U50488 (10 mg/kg, i.p.) and LiP + levetiracetam (400 mg/kg, i.p.) group. SE was terminated after 90 min of its onset with diazepam (15 mg/kg, i.p.) and phenobarbitone (25 mg/kg, i.p.). Drug treatment was started after 15 min of onset of SE and repeated once after 4 h. Rats were video monitored 12 h daily (9 AM to 9 PM) to determine severity of SE using modified Racine scale and onset and frequency of SS from day 0 to day 21. Morris water maze (MWM) test was done at baseline i.e. day -1 (before lithium administration) and day 22, to assess cognitive impairment.

RESULTS

As compared to LiP, U50488 decreased the severity of SE (1.98 ± 0.13 vs 2.95 ± 0.12; p-value < 0.0001) but not levetiracetam (2.62 ± 0.09; p-value = 0.3112). Survival increased with both U50488 (90%, n = 10) and levetiracetam (81.8%, n = 11) as compared to NS (56.2%, n = 16). No effect on onset and frequency of SS was found in U50488/levetiracetam group. U50488 improved seizures-induced cognitive impairment. Levetiracetam group showed thigmotactic (wall hugging) behaviour in MWM in 8 out of 9 rats.

CONCLUSION

Acute treatment with U50488, a kappa opioid receptor agonist has a beneficial effect on SE, SE-related mortality and memory impairment. The dual protective effect of U50488 on seizures and related cognitive impairment is advantageous over currently used antiseizure drugs which are known to cause cognitive impairment.

1147 MORPHO-FUNCTIONAL EVALUATION OF 3MG/KG ICV-STZ RAT SHOWED SPORADIC ALZHEIMER'S LIKE PATHOLOGY WITH PROGRESSIVE DEMENTIA

Background

Intracerebroventricular streptozotocin (ICV-STZ) injection is among the best animal models to simulate sporadic Alzheimer’s disease (sAD). Abnormality in brain insulin signalling, neurodegeneration, neuroinflammation, cholinergic damage, mitochondrial dysfunction, genetic abnormality, respiratory problem, oxidative stress, gliosis, sleep disturbances are associated with cognitive abnormalities seen in ICV-STZ injected rats. Available experimental evidence has used varying doses of STZ (&lt;1 to 3mg/kg) and studied its effect for different study durations, ranging from 14-21 (short), 30-42 (mild), 90-105 (moderate) and 250-270 (long) days. These studies indicated that 3mg/kg of body-weight is the optimum dose for inducing sAD in the rodents. However, studies on the pathological process with related the morphological and functional abnormalities reported were illusive.

Objective/Method

Hence in the present study, we have investigated the morpho-functional changes after 3mg/kg ICV-STZ treatment with a follow-up of two months in 54 male Wistar rats (ethical no. 937/IAEC/PhD-2016).

Results

Exhibited a spatial, episodic and avoidance memory decline and increase in anxiety (p&lt;0.05) in ICV-STZ group progressively with time from 15th day to 60th day post-injection. Morphometry showed hippocampal atrophy with CA1, CA3 layer thinning (p ≤0.01) and loss of neurons (p&lt;0.0001) associated with third ventricular enlargement (p= 0.007) in ICV-STZ rats versus sham, along-with extracellular amyloid plaque in AD rats with Congored staining. In addition, spine morphometry with Golgi-Cox impregnation of mossy fibre showed a reduction of spine density in AD group versus control and sham group (p&lt;0.0001). Finally, immunohistochemistry of GSK3ß, PI3K and mtCOX-1 antigen in coronal sections revealed an increase in mean intensity of GSK3ß and decrease in PI3K and mtCox-1 in brain areas associated with limbic system in ICV-STZ group on 60th day.

Conclusion

These findings suggest progressive dementia and anxiety in 3mg/kg STZ treated rats, which may be due to hippocampal atrophy, amyloidopathy, ventricular enlargement, synaptic dysfunction and deficits in energy homeostasis of brain.

1145 RTMS TREATMENT IMPROVED COGNITIVE DYSFUNCTION THROUGH ADULT NEUROGENESIS IN ICV-STZ RAT MODEL OF SPORADIC ALZHEIMER'S DISEASE

Background

Intracerebroventricular streptozotocin injection at 3mg/kg of b/w causes phenotypes similar to that of sporadic Alzheimer’s disease (sAD) from 14th day post-injection. On the other hand, the body of evidence indicated that impairment in the sAD is the major contributor for cognitive decline. Taken together, we tested the adult neurogenesis hypothesis in streptozotocin model of sAD in female Wistar rats after extremely low magnetic stimulation (MF: 17.96, 50Hz, 2hr/day, 21days).

Method

33 rats were randomly divided into three groups viz. Sham+MF, AD and AD+MF. Consequently, animals were first induced AD with stereotaxic manipulation and then they were exposed to low frequency magnetic field stimulation, followed by terminal cognitive behavioural tasks brain tissue being isolated for both biochemical and subcellular expression experiments (ethical no. 12/IAEC-1/2017).

Results

Showed reduction in latency to the goal quadrant (p= 0.002) and transfer latency (p= 0.045) in AD+MF group versus AD. Even, Dirichlet distribution of time spent in 4 quadrants indicated un-uniform in all the groups except AD group (p= 0.067, LRS= 7.35). Further, cell count in CA3 and DG exhibited increase in cell density in AD+MF group (p&lt;0.05). However, we found significant reduction in SOD1 activity after MF treatment (p= 0.035) but no change in GSH level in hippocampus and frontal cortex. Interestingly, these changes in AD+MF animals are associated with increase in density of BrdU+/Nestin+ cells in granular layer (p= 0.002) and hilus region (p= 0.0005) of DG along with increase in expression of L-type Ca2+ channels as compared to AD group.

Conclusion

This experimental evidence suggests that non-invasive brain stimulation can promote adult neurogenesis by activating L-type ca2+ channels in the hilus, which intern helps in retention of long-term memory even after sAD.

Cognitive Dysfunction and Anxiety Resulting from Synaptic Downscaling, Hippocampal Atrophy, and Ventricular Enlargement with Intracerebroventricular Streptozotocin Injection in Male Wistar Rats

Insulin-resistant brain state is proposed to be the early sign of Alzheimer's disease (AD), which can be studied in the intracerebroventricular streptozotocin (ICV-STZ) rodent model. ICV-STZ is reported to induce sporadic AD with the majority of the disease hallmarks as phenotype. On the other hand, available experimental evidence has used varying doses of STZ (< 1 to 3 mg/kg) and studied its effect for different study durations, ranging from 14 to 270 days. Though these studies suggest 3 mg/kg of ICV-STZ to be the optimum dose for progressive pathogenesis, the reason for such is elusive. Here, we sought to investigate the mechanism of action of 3 mg/kg ICV-STZ on cognitive and non-cognitive aspects at a follow-up interval of 2 weeks for 2 months. On the 60th day, we examined the layer thickness, cell density, ventricular volume, spine density, protein expression related to brain metabolism, and mitochondrial function by histological examination. The findings suggest a progressive loss of a spatial, episodic, and avoidance memory with an increase in anxiety in a span of 2 months. Furthermore, hippocampal neurodegeneration, ventricular enlargement, diffused amyloid plaque deposition, loss of spine in the dentate gyrus, and imbalance in energy homeostasis were found on the 60th day post-injection. Interestingly, AD rats showed a uniform fraction of time spent in four quadrants of the water maze with a change in strategy when they were exposed to height. Our findings reveal that ICV-STZ injection at a dose of 3 mg/kg can cause cognitive and neuropsychiatric abnormalities due to structural loss both at the neuronal as well as the synaptic level, which is tightly associated with the change in neuronal metabolism.

Effect of morphine administration after status epilepticus on epileptogenesis in rats

INTRODUCTION

Morphine is widely used in patients and has been reported to alter seizure threshold, but its role in the development of epilepsy is unknown. In this study, role of morphine administration in the development of epilepsy using the status epilepticus (SE) model was determined in rats.

METHODS

Rats experiencing SE with lithium-pilocarpine (LiP) were randomized into four groups- saline, morphine low dose (5 mg/kg, s.c.), morphine high dose (5-20 mg/kg, s.c.), and naloxone (1 mg/kg, s.c.). Treatments were started 90 min after termination of SE and repeated twice daily for next three days. Rats were video monitored daily for 21 days to determine onset and frequency of spontaneous convulsive seizures (SS).

RESULTS

Morphine in low doses increased frequency of SS (1.51 ± 0.15 vs LiP 0.60 ± 0.12 seizures/rat/day, p-value = 0.0026) and seizures occurred during handling (SDH) (0.08 ± 0.02 vs LiP control 0.01 ± 0.01) (p-value = 0.0018). In high doses, no significant change in SS and SDH was found as compared to LiP. No effect of morphine on the onset of SS and percentage of rats experienced SS was found. No effect of naloxone per se was found on SS.

CONCLUSION

Morphine administration after SE does not affect epileptogenesis as no change in the onset of SS and percentage of rats experiencing SS was found. However, it might alter the susceptibility and frequency of SS. As no other study is available with a similar finding, it needs further evaluation.

Characterization of potentially inappropriate medications use in Indian elderly population and their impact on quality of life using Beers criteria

Background

Methods

Results

Conclusion

Point prevalence of depression in persons with active epilepsy and impact of methodological moderators: A systematic review and meta-analysis

OBJECTIVES

The aim of this study was to determine the pooled prevalence of depression in persons with epilepsy and assess the methodological moderators affecting the prevalence estimates.

METHODS

Five electronic databases PubMed, The Cochrane Library, EMBASE, WHO Global Index Medicus, and Clinicaltrial.gov were searched for studies reporting prevalence of depression in PWE ≥ 18 years of age in any setting.

RESULTS

Out of 13,873 studies, after deduplication and screening, 56 studies with 10,527 PWE met the eligibility criteria. The overall pooled prevalence of depression in PWE was 32% (95%confidence interval [CI] 28-35%) and significant heterogeneity (Chi-square = 1171.53, p = 0.00; τ² = 0.02; I² = 94.36%). Prevalence has doubled in the recent years (16% in 2000-2005 vs. 35% in 2016-2020), was higher in Asia than in Europe (coefficient 0.899, 95%CI: 0.809-0.999; p = 0.049). Among assessment methods, prevalence was highest in HAM-D scale (54%, 95%CI: 27-82%) and lowest in MINI (22%, 95%CI: 19-26%). Sensitivity analysis also corroborated findings when MINI was excluded (35%, 95%CI: 31-38%).

CONCLUSIONS

A significant proportion of PWE have depression. Though there is substantial heterogeneity due to various methodological moderators, it is unlikely to affect the routine screening of PWE for depression. Use of a screening tool should be based on ease of administration, and cutoff selection should ensure identification of minimal depression as well.

Response to sertraline and antiepileptic drugs in pentylenetetrazole kindling in rats

Anti-epileptic drugs (AEDs) are the mainstay of epilepsy treatment but these may be a potential risk factor for behavioral disturbances particularly depression which requires treatment. In this study, the effect of antidepressant sertraline (SRT) in combination with AEDs sodium valproate (SV) and levetiracetam (LEV) on seizures, cognitive impairment and oxidative stress in rats was evaluated. After administration of 24th injection of pentylenetetrazole (PTZ), 77.8% rats were kindled. Administration of SRT showed no protective effect on kindling development while SV was 100% protective. With LEV 42.9% were kindled. On combining SRT with SV or LEV 25% and 20% rats were kindled. A significant increase in latency to reach platform zone in Morris water maze(MWM), and increased transfer latencies in Elevated plus maze(EPM) was observed in PTZ kindled rats as compared to normal control on day 49 and when LEV was combined with SRT. In EPM test, however none of the drug treatments had any effect on transfer latencies except LEV pretreated kindled group. In Passive avoidance (PA) test, kindling was associated with a significant decrease in retention time(p = 0.018) while LEV and SV had no effect. The PTZ kindled rats showed significantly higher malondialdehyde(MDA) levels in brain hippocampus(p = 0.0286) while both SRT and SV were associated with significantly lower MDA levels as compared to kindled control group. In case of glutathione (GSH), kindling had no significant effect. The use of sertraline for depression in persons with epilepsy on AEDs needs to be carefully evaluated and monitored due to likelihood of individual variation.

Prevalence of depression and suicidal ideation in persons with epilepsy during the COVID-19 pandemic: A longitudinal study from India

OBJECTIVES

COVID-19 pandemic has disrupted healthcare services for chronic disorders such as epilepsy. In this study, the impact of COVID-19 pandemic on persons with epilepsy (PWE) with regard to their seizure control, depression status, and medication adherence was assessed.

METHODS

After ethical clearance, 449 PWE who had been previously evaluated for depression at All India Institute of Medical Sciences (AIIMS), New Delhi, India, were telephonically revaluated using Mini International Neuropsychiatric Interview and surveyed for source of medication and medication adherence over past 6 months. The prevalence and the association of depression, suicidality, and seizures during pandemic with different PWE variables were determined.

RESULTS

Out of 449 PWE, 70.6% responded. 19.9% were diagnosed positive for depression as per MINI while suicidal ideation was observed in 5.4%. Seventy six (23.9%) PWE reported seizures during pandemic. The incidence was greater in females, unemployed, previously uncontrolled epilepsy, polytherapy, altered use of medications, and depressed PWE. Seizure during pandemic, increased seizure frequency, previous history of depression, and altered use of medications were all significantly associated with depression during COVID-19 pandemic (2.6-95%CI, 1.45-4.73; 1.9-95%CI, 1.01-3.57; 8.8-95%CI, 4.54-17.21; 2.9-95%CI, 1.19-7.24), and polytherapy (2.9-95%CI, 0.92-9.04), seizures during pandemic (3.9-95%CI, 1.45-10.53) and previous history of depression and suicidality, were related with suicidal ideation.

CONCLUSION

COVID-19 pandemic-induced disruptions can be detrimental for PWE, and restoring services to the precovid levels as well as putting appropriate continuity plans in place for care of PWE should be a priority.

Depression in persons with epilepsy: A comparative study of different tools in Indian population

OBJECTIVE

Depression is an important co-morbidity in persons with epilepsy (PWE) and its timely identification is essential. The aim of the study was to assess and compare the psychometric properties of potentially suitable screening tools of depression in PWE in a tertiary care setting in India.

METHODS

After ethical clearance, 449 PWE above 18 years of age, on anti-seizure drugs (ASDs), attending epilepsy clinic in neurology outpatient department (OPD) of All India Institute of Medical Sciences, New Delhi, India, were recruited and evaluated for depression using different tools namely: Neurological Disorders Depression Inventory for Epilepsy (NDDI-E), Patient Health Questionnaire (PHQ-9) and Hamilton Depression Rating Scale (HAM-D). Mini International Neuropsychiatric Interview (MINI: Module A, version 6.0.0) was used as reference standard. The association if any of depression with PWE variables was also determined.

RESULTS

A variable percentage of PWE were positive for depression- 40.1% with MINI, 40.5% with NDDI-E, 44.3% with HAM-D and 45.4% with PHQ-9. Suicidal ideation was present in 4.5% of PWE. The sensitivity and specificity of scales using MINI as a reference standard were found to be maximal at scores ≥5, ≥8 and >11 for PHQ-9, HAM-D, and NDDI-E, respectively. The ROC analysis revealed a statistically significant difference among NDDI-E and PHQ-9 (p = 0.0268). Polytherapy in PWE had significant association with risk of depression (p < 0.01) and female PWE had 1.5 times the odds of depression as compared with males (95% CI, 1.02-2.2).

CONCLUSION

All the tools used in this study were found to be appropriate for use in PWE if cut-off points are validated. The choice of tool can be based on the clinical setting.

Impact of increased focus on pharmacovigilance on knowledge and attitude towards adverse drug reaction reporting among medical students in India

BACKGROUND

Recent years have seen a surge in pharmacovigilance (PV) related activities in India. In the present study the impact of these initiatives on medical students from across the country was evaluated to identify their effectiveness, lacunae and arrive at remedial measures.

METHODS

A cross-sectional, questionnaire based study was conducted. The survey questionnaire consisted of 28 multiple response items. The areas covered included subject knowledge (theoretical and practical), attitude and awareness towards pharmacovigilance.

RESULTS

The survey participants (n = 253) were from 71 medical colleges and 17 states across India. While 60% of the participants were familiar with the term 'Pharmacovigilance', many could not distinguish side effect and adverse drug reaction. The majority was unaware that 'Periodic Safety Update Report' (PSURs) is a mandatory pharmacovigilance activity by the industry. 91% felt reporting is a useful practice and causes for under-reporting are a lack of awareness followed by attitude, misconceptions about what to report, fear of litigation and interestingly the least important is lack of time. However, most were reluctant to have reporting as mandatory tool; they would rather use it voluntary.

CONCLUSION

In spite of collaborative and synchronized efforts by various agencies there is a need to further improve the PV milieu in India by confidence building exercises, imparting training on PV programme, updating of the current knowledge on PV and also sustaining motivation.

An interaction study of Ocimum sanctum L. and levetiracetam in pentylenetetrazole kindling model of epilepsy

ETHNOPHARMACOLOGICAL RELEVANCE

Ocimum sanctum L. commonly known as tulsi (synonym of Ocimum tenuiflorum L.) is widely used in Ayurveda medicine and is having multitude neuromodulatory effect including the anticonvulsant effect in acute seizure models as per previous studies. In India, it is used for the treatment of epilepsy as traditional medicine. However, its role in chronic seizure model and interaction with newer antiepileptic drugs has not been investigated, which will enhance its translational value.

AIM OF THE STUDY

Current study investigated the effect of Ocimum on chronic seizure model and its interaction with levetiracetam (LEV), a newer antiepileptic drug.

MATERIALS AND METHODS

The adjuvant role of Ocimum sanctum hydroalcoholic extracts (OSHE) 1000 mg/kg along with LEV 300 mg/kg was studied in adult male Wistar rats with mean weight of 227.84 ± 21.68 g using pentylenetetrazole (30 mg/kg, i.p.) kindling (K) (with maximum 24 injections on alternate days and challenge on 7th-day). Along with seizure score, neurobehavioral, brain tissue oxidative stress and histopathology status were assessed. Pharmacokinetic interaction was assessed between LEV and OSHE after 14 days of drug treatment.

RESULTS

K-LEV + OSHE had least seizure score during kindling and on the pentylenetetrazole-challenge test (p=0.031) than other kindling groups. Seizure protection was more in K-LEV + OSHE (85.72%) than others (K-LEV-42.86%, K-OSHE-42.86%, and K-Control-28.58%). Ocimum treated groups had better memory retention potential as evident from Morris water maze (MWM), passive avoidance test but not in an elevated plus maze test. Oxidative-stress was lower in Ocimum treated groups than K-Control group. As per histopathology, K-LEV + OSHE group had the least neuronal degeneration among kindling groups. There was no significant pharmacokinetic interaction between LEV and OSHE, except increased T_max in LEV + OSHE group than LEV alone (p=0.009).

CONCLUSIONS

Ocimum per se and combination with levetiracetam treatment exerted better seizure control, memory retention, oxidative stress reduction, and neuronal structure preservation than kindling control group. There was a very minimal drug interaction between Ocimum and LEV. So, Ocimum as an adjuvant to LEV may be shelpful in enhancing the antiepileptic effect and also in minimizing the adverse effects.

Validation of the Indian version of Neurological Disorders Depression Inventory for Epilepsy (NDDI-E)

PURPOSE

The Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) is an efficient tool for rapid detection of depression, an important comorbid condition in persons with epilepsy (PWE). Since social and cultural differences can potentially affect the cutoff score of NDDI-E, in this study, the reliability and validity of the Indian version of the NDDI-E in PWE was determined.

METHOD

After ethical clearance, 217 PWE above 18 years of age, on antiepileptic drugs (AEDs), attending neurology outpatient department (OPD) of All India Institute of Medical Sciences (AIIMS), New Delhi, India, were evaluated for depression using the NDDI-E (Indian version) and Mini International Neuropsychiatric Interview (MINI-Module A, version 6.0.0) as reference standard. Informed consent was taken before recruitment. Receiver operating characteristic (ROC) analysis and Cronbach's α, a measure of the internal consistency and reliability, were carried out to validate cutoff and questionnaire, respectively.

RESULTS

Of the 217 PWE (112 males/105 females), mean age of 28.6 ± 9.4 years, with generalized (69.1%) or focal seizures (30.9%), 41.5% and 10.6% were diagnosed with depression using MINI and NDDI-E Indian version (at cutoff >15), respectively. However, at a cutoff score of >11, the Indian version of NDDI-E had a sensitivity of 96.67%, a specificity of 84.25%, a positive predictive value of 81.31%, and a negative predictive value of 97.27%. ROC analysis showed an area under the curve (AUC) of 0.9547 (confidence interval (CI) 95% = 0.929-0.979; standard error (SE): 0.0127). With the Indian version of NDDI-E, the Cronbach's α value was 0.877.

CONCLUSION

A periodic assessment of PWE using a quickly administrable and reliable tool for screening depression is highly desirable given the high incidence. In the Indian population with a cutoff of >11, NDDI-E is a reliable and valid instrument to screen depression in PWE.

Anticonvulsant activity of the cyclooxygenase-2 (COX-2) inhibitor etoricoxib in pentylenetetrazole-kindled rats is associated with memory impairment

PURPOSE

Various selective and nonselective cyclooxygenase (COX) inhibitors are known to have effects on development and progression of seizures. In the present study, the effect of the selective COX-2 inhibitor etoricoxib on seizures, oxidative stress, and learning and memory was studied.

METHOD

Male Wistar rats were kindled using subconvulsant dose of pentylenetetrazole (PTZ) (30mg/kg, i.p.), on alternating days until animals were fully kindled. After a one-week PTZ-free period, kindled rats were challenged with PTZ 30mg/kg, and the latency, duration, and severity of seizures were recorded. Etoricoxib was then administered intraperitoneally at 1mg/kg and 10mg/kg in kindled rats for nine days (days 6-14). On the ninth day of etoricoxib treatment, PTZ challenge (30mg/kg) was given, and seizure parameters were noted. On day 15, behavioral assessment was carried out. The Morris water maze (MWM) apparatus and the passive avoidance (PA) apparatus were used for studying cognitive impairment. The rats were then sacrificed, and malondialdehyde (MDA) and glutathione (GSH), markers of oxidative stress, were estimated in the brain samples.

RESULTS

Etoricoxib at lower dose (1mg/kg) had an anticonvulsant effect which was reduced or reversed at higher dose (10mg/kg). Etoricoxib also impaired the learning and memory in rats as tested by passive avoidance and Morris water maze tests.

CONCLUSION

The results of the present study suggest that use of etoricoxib, especially at low dose, in patients with epilepsy may not be detrimental with regard to seizure control. However, attention should be paid to cognitive parameters.

Low dose zinc supplementation beneficially affects seizure development in experimental seizure models in rats

The role of zinc in seizure models and with antiepileptic drugs sodium valproate (SV) and phenytoin (PHT) was studied using experimental models of seizures in rats. Male Wistar rats, 150-250 g were administered zinc 2, 20, and 200 mg/kg, orally for 14 days. Sixty minutes after the last dose of zinc, rats were challenged with pentylenetetrazole (PTZ, 60 mg/kg, ip) or maximal electroshock (MES, 70 mA, 0.2 s duration). In another group, SV (150/300 mg/kg, ip) or PHT (40 mg/kg, ip) was administered after 30 min of zinc administration followed by seizure challenge. Zinc pretreatment at all doses had no effect on MES seizures. In PTZ seizures, with the lowest dose used, i.e., 2 mg/kg, a protective effect was observed. Neither the protection offered by the 100 % anticonvulsant dose of SV (300 mg/kg) in PTZ seizures was affected by pre-treatment with zinc nor a combination of subanticonvulsant dose of SV (150 mg/kg) and zinc offer any statistically significant advantage over either drug alone. The combination of phenytoin with zinc had no effect on any of the parameters tested. Apart from this, chronic zinc administration hampered development of chemically (PTZ)-kindled seizures in rats. Zinc supplementation is unlikely to have any undesirable effect when used in epileptics rather it may offer advantage in epileptic and seizure prone patients.

Interaction of hydroalcoholic extract of Acorus calamus Linn. with sodium valproate and carbamazepine

Anticonvulsant property of Acorus calamus is known. Since combination therapy can lower the dose of individual drug and dose related toxicities, in this study, the effect of co-administration of hydroalcoholic extract of A. calamus (HAEAC) on conventional antiepileptic drugs (AEDs), sodium valproate and carbamazepine was determined using pentylenetetrazole-induced seizures model in rats. On combining the subanticonvulsant doses of HAEAC with sodium valproate and carbamazepine, greater protection as compared to either drug alone was observed. This was not related to change in levels of the AEDs. Thus, the results further substantiate anticonvulsant effect of HAEAC and suggest a potential for add on therapy with AEDs.

Dopamine release is involved in antinociceptive effect of theophylline

The methylxanthines, e.g., theophylline, are widely used for the treatment of bronchial asthma. Additionally, a pain relieving effect of theophylline has been reported in patients as well as in experimental animals. The mechanism of this antinociceptive action is not clear. In this study, involvement of dopaminergic system in theophylline-induced antinociception was evaluated using tail flick test model. Swiss albino mice, (either sex, weighing 25-30 g) with base line tail flick latencies (TFL) between 2.0 and 3.5 s, were used. TFL was recorded before and at intervals of 15, 30, 45, and 60 min. after drug treatment. The experimental protocol was duly approved by the Institutional Animal Ethics Committee, All India Institute of Medical Sciences, New Delhi, India. To determine the role of dopaminergic system, the mice were pretreated with either D1 or D2 dopaminergic receptor antagonists SCH 23390 and haloperidol, respectively, prior to treatment with theophylline. Another group of animals received apomorphine along with theophylline. The dose of theophylline used, i.e., 10 mg/kg, intraperitoneally (i.p.), had shown a significant increase in TFLs. The theophylline-induced antinociception, 10 mg/kg, i.p., was reversed by pretreatment with both D1 and D2 dopaminergic receptor antagonists SCH 23390 and haloperidol as well as with apomorphine (1 mg/kg) pretreatment. The results suggest that theophylline-induced antinociception is due to release of dopamine.

Evaluation of antitussive activity of formulations with herbal extracts in sulphur dioxide (SO2) induced cough model in mice

Cough is the most common symptom of respiratory diseases. When cough becomes serious, opioids are effective, but they have side effects like sedation, constipation, some addiction liability and also compromise the respiratory function. Therefore, there is need to have effective anti-tussive agent which do not have respiratory suppressant activity. The present study was carried out to evaluate anti-tussive activity of combination of herbal drugs as formulations in sulphur dioxide (SO2)-induced cough model in mice. Albino mice of either sex, weighing 25-30 g were divided into eight groups, (n = 6). Group 1 served as normal control, group 2 mice were given distilled water, group 3 was positive control and received codeine sulphate (10 mg/kg, p.o.) and group 4, 5, 6, 7 received coded 1 formulations 1, 2, 3 and 4 respectively at a dose of 0.3 ml/mice, orally, while group VIII was the vehicle control. Thirty minutes later, the mice were exposed to sulphur dioxide again for 45 sec. The mice were then placed in an observation chamber for counting of cough bouts, by two independent observers, for five minutes. All the formulations used showed significant antitussive activity in sulphur dioxide induced cough model. Thus, these formulations can prove to be useful for alleviating cough.