Intrathecal Lamotrigine Attenuates Mechanical Allodynia and Suppresses Microglial and Astrocytic Activation in a Rat Model of Spinal Nerve Ligation

Purpose

Lamotrigine, a novel anticonvulsant, is a sodium channel blocker that is efficacious in certain forms of neuropathic pain. Recently, microglial and astrocytic activation has been implicated in the development of nerve injury-induced neuropathic pain. We have assessed the effects of continuous intrathecal administration of lamotrigine on the development of neuropathic pain and glial activation induced by L5/6 spinal-nerve ligation in rats.

Materials and Methods

Following left L5/6 spinal nerve ligation (SNL), Sprague-Dawley male rats were intrathecally administered lamotrigine (24, 72, or 240 µg/day) or saline continuously for 7 days. Mechanical allodynia of the left hind paw to von Frey filament stimuli was determined before surgery (baseline) and once daily for 7 days postoperatively. On day 7, spinal activation of microglia and astrocytes was evaluated immunohistochemically, using antibodies to the microglial marker OX-42 and the astrocyte marker glial fibrillary acidic protein (GFAP).

Results

Spinal-nerve ligation induced mechanical allodynia in saline-treated rats, with OX-42 and GFAP immunoreactivity being significantly increased on the ipsilateral side of the spinal cord. Continuously administered intrathecal lamotrigine (240 µg/day) prevented the development of mechanical allodynia, and lower dose of lamotrigine (72 µg/day) ameliorated allodynia. Intrathecal lamotrigine (72 and 240 µg/day) inhibited nerve ligation-induced microglial and astrocytic activation, as evidenced by reduced numbers of cells positive for OX-42 and GFAP.

Conclusion

Continuously administered intrathecal lamotrigine blocked the development of mechanical allodynia induced by SNL with suppression of microglial and astrocytic activation. Continuous intrathecal administration of lamotrigine may be a promising therapeutic intervention to prevent neuropathy.     

Genetic predictors for acute experimental cold and heat pain sensitivity in humans

Background

The genetic contribution to pain sensitivity underlies a complex composite of parallel pain pathways, multiple mechanisms, and diverse inter‐individual pain experiences and expectations.

Methods

Variations for genes encoding receptors related to cold and heat sensation, such as transient receptor potential A subtype 1 (TRPA1), M subtype 8 (TRPM8), V subtype 1 (TRPV1), δ opioid receptor subtype 1 (OPRD1), catechol O‐methyltransferase (COMT), and fatty acid amide hydrolyase (FAAH), were investigated in four major ethnic populations.

Results

We defined 13 haplotype blocks in European Americans, seven blocks in African Americans, seven blocks in Hispanic subjects, and 11 blocks in Asian Americans. Further study in European American subjects found significant associations between short duration cold pain sensitivity and variations in TRPA1, COMT, and FAAH in a gender dependent manner. Our observations demonstrate that genetic variations in TRPA1, COMT, and FAAH contribute gender specifically to individual variations in short duration cold pain sensitivity in a European American cohort.

Conclusions

The effects of TRPA1 variations on experimental short duration heat pain sensitivity may contribute to inter‐individual variation in pain sensitivity in humans.     

Study on the Inhibitory Effect of Total Alkaliods of Sophora Alopecuroides on Osteosarcoma Cell Growth

Background

Ku Dou Zi is the dried whole plant, roots and seeds of Sophora alopecuroides L. in the genus Sophora of family Leguminosae. The entire plant is bitter in taste, cold in nature, and has the heat clearing, detoxifying, pathogenic wind dispelling dampness, analgesic, and insecticidal effects. Modern pharmacological studies have proved that TASA has pharmacological activities of anti-cancer. The objective of this paper was to investigate the inhibitory effect of total alkaloids of Sophora alopecuroides (TASA), on osteosarcoma cell growth and its mechanism.

Materials and Methods

MTT assay and flow cytometry were used to study the inhibitory effect of TASA on human osteosarcoma cell line OS732.

Results

The results showed that the inhibition rates of different concentrations of TASA (1.5, 3, and 4.5g/kg), against human osteosarcoma cell line OS732, were: 18.4%, 27.4% and 52.8%, respectively.

Conclusion

TASA has an inhibitory effect on osteosarcoma cell growth.     

Anti-seizure activity of the aqueous leaf extract of Solanum nigrum linn (solanaceae) in experimental animals

Background

Solanum nigrum is claimed in traditional medical practice, to be useful in the treatment of epilepsy in some parts of Nigeria.

Objectives

To study the anti-convulsant property of the aqueous extract of the leaves of S. nigrum in chicks, mice and rats.

Method

Aqueous extracts were administered intraperitoneally, at a pre-treatment time of 30 minutes, at graded doses and animals were challenged with different types of proconvulsants.

Results

The aqueous leaf extract produced a significantly (P<0.05) dose dependent protection against electrically-induced seizure in chicks and rats, pentylenetetrazole-induced seizure in mice and rats and picrotoxin-induced seizure in mice and rats. The anti-seizure property of the extract was potentiated by amphetamine.

Conclusion

The result obtained in this study suggests that the leaves of this plant may possess anti-convulsant property in chicks, mice and rats.     

Self-paced exercise performance in the heat after pre-exercise cold-fluid ingestion

Context:

Precooling is the pre-exercise reduction of body temperature and is an effective method of improving physiologic function and exercise performance in environmental heat. A practical and effective method of precooling suitable for application at athletic venues has not been demonstrated.

Objective:

To confirm the effectiveness of pre-exercise ingestion of cold fluid without fluid ingestion during exercise on pre-exercise core temperature and to determine whether pre-exercise ingestion of cold fluid alone without continued provision of cold fluid during exercise can improve exercise performance in the heat.

Design:

Randomized controlled clinical trial.

Setting:

Environmental chamber at an exercise physiology laboratory that was maintained at 32°C, 60% relative humidity, and 3.2 m/s facing air velocity.

Patients or Other Participants:

Seven male recreational cyclists (age = 21 ± 1.5 years, height = 1.81 ± 0.07 m, mass = 78.4 ± 9.2 kg) participated.

Intervention(s):

Participants ingested 900 mL of cold (2°C) or control (37°C) flavored water in 3 300-mL aliquots over 35 minutes of pre-exercise rest.

Main Outcome Measure(s):

Rectal temperature and thermal comfort before exercise and distance cycled, power output, pacing, rectal temperature, mean skin temperature, heart rate, blood lactate, thermal comfort, perceived exertion, and sweat loss during exercise.

Results:

During rest, a greater decrease in rectal temperature was observed with ingestion of the cold fluid (0.41 ± 0.16°C) than the control fluid (0.17 ± 0.17°C) over 35 to 5 minutes before exercise (t₆ = −3.47, P = .01). During exercise, rectal temperature was lower after ingestion of the cold fluid at 5 to 25 minutes (t₆ range, 2.53–3.38, P ≤ .05). Distance cycled was greater after ingestion of the cold fluid (19.26 ± 2.91 km) than after ingestion of the control fluid (18.72 ± 2.59 km; t₆ = −2.80, P = .03). Mean power output also was greater after ingestion of the cold fluid (275 ± 27 W) than the control fluid (261 ± 22 W; t₆ = −2.13, P = .05). No differences were observed for pacing, mean skin temperature, heart rate, blood lactate, thermal comfort, perceived exertion, and sweat loss (P > .05).

Conclusions:

We demonstrated that pre-exercise ingestion of cold fluid is a simple, effective precooling method suitable for field-based application.     

Assessing cold chain status in a metro city of India: an intervention study

Background

Cold chain maintenance is an essential activity to maintain the potency of vaccines and to prevent adverse events following immunization. One baseline study highlighted the unsatisfactory cold chain status in city of Kolkata in India.

Objectives

To assess the changes which occurred in the cold chain status after the intervention undertaken to improve the status and also to assess the awareness of the cold chain handlers regarding cold chain maintenance.

Methods

Intervention consisted of reorganization of cold chain points and training of health manpower in Kolkata Municipal area regarding immunization and cold chain following the guidelines as laid by Govt of India. Reevaluation of cold chain status was done at 20 institutions selected by stratified systematic random sampling after the intervention. The results were compared with baseline survey.

Results

Significant improvement had been observed in correct placing of cold chain equipment, maintenance of stock security, orderly placing of ice packs, diluents and vaccines inside the equipment, temperature recording and maintenance. But awareness and skill of cold chain handlers regarding basics of cold chain maintenance was not satisfactory.

Conclusions

The success of intervention included significant improvement of cold chain status including creation of a designated cold chain handler. The gaps lay in non-availability of non-electrical cold chain equipment and separate cold chain room, policy makers should stress. Cold chain handlers need reorientation training regarding heat & cold sensitive vaccines, preventive maintenance and correct contingency plan.     

Antidiabetic and haematinic effects of Parquetina nigrescens on alloxan induced type-1 diabetes and normocytic normochromic anaemia in Wistar rats

Background

The plant, Parquetina nigrescens is used in folklore medicine to treat diabetes mellitus and its complications in several parts of West Africa.

Objective

To determine the effect of Parquetina nigrescens extract on fasting blood glucose in alloxan-induced diabetic rats.

Methods

The blood glucose levels, complete blood count, erythrocyte indices and osmotic fragility, body and organ weights were evaluated.

Results

Diabetic rats treated with the extract showed significant (P<0.01) reduction of the blood glucose to levels comparable to that of the non-diabetic control and those treated with chlorpropamide (standard drug). Similarly, there was significant (P<0.01) reduction in the complete blood count in the diabetic rats.

Discussion

The anaemia, leucopenia and thrombocytopenia associated with the diabetes were corrected in the animals treated with the extract and chlorpropamide. The extract also reduced the erythrocyte osmotic fragility, body and organ weights. Parquetina nigrescens demonstrated antidiabetic property by reducing the elevated blood glucose in alloxan treated rats which is comparable to animals that received the standard drug.

Conclusion

Paraquetina nigrescens stabilized the erythrocyte membrane, decreased the body weight probably by lowering lipogenesis. However, the mechanism underlying the antidiabetic and haematinic properties of Parquetina nigrescens remains to be elucidated.     

Modafinil Prevents Inhibitory Avoidance Memory Deficit Induced by Sleep Deprivation in Rats

Study Objectives:

Evaluation of modafinil effects on the inhibitory avoidance task (IA).

Design:

Rats were trained on a multiple trial IA task after receiving modafinil or vehicle injections. In experiment 1 they were trained with a weak protocol under baseline condition and in experiment 2, with a stronger protocol under sleep-deprivation condition.

Results:

In experiment 1 modafinil improved rats'' acquisition whereas the retention test remained unaffected. In Experiment 2 modafinil did not interfere with training performance, but the lower dose prevented the retention impairment in sleep-deprived animals.

Conclusions:

Modafinil is able to improve acquisition in normal rats and reverse the long-term memory impairment induced by sleep-deprivation.

Citation:

Moreira KM; Ferreira TL; Hipolide DC; Fornari RV; Tufik S; Oliveira MGM. Modafinil prevents inhibitory avoidance memory deficit induced by sleep deprivation in rats. SLEEP 2010;33(7):990-993.     

Antihypercholesterolemic activity of ethanolic extract of Buchholzia coriacea in rats

Background

Hypercholesterolemia is a condition characterised with high level of cholesterol in the blood.

Objectives

The effect of ethanolic extract of Buchholzia coriacea (EEBC) on the lipid profile levels and extent of lipid peroxidation in hypercholesterolemic albino rats was investigated in this study.

Methods

Thirty albino rats were divided into six different groups which consist of group 1 (control), group 2 (hypercholesterolemic rats), group 3 (hypercholesterolemic rats treated with ethanolic extract of EEBC), group 4 (hypercholesterolemic rats treated with questran), group 5 (normal rats treated with EEBC) and group 6 (normal rats treated with questran). The rats were sacrificed at the end of the sixth week and assay conducted for Aspartate Transaminase (AST), Alanine Transaminase (ALT), lipid profile and biomarker of oxidative stress.

Results

The serum and liver total cholesterol and LDL - cholesterol levels as well as lipid peroxidation in the EEBC-treated hypercholesterolemic rats were significantly reduced (p < 0.05) when compared with the untreated hypercholesterolemic rats. The activities of AST and ALT in EEBC - treated hypercholesterolemic rats were not significantly different (p > 0.05) from the control.

Conclusions

The results suggest that Buchholzia coriacea seeds contain potent antihypercholesterolemic agent which may find clinical application in ameliorating hypercholesterolemia and its attendant complications.     

The effects of heat and massage application on autonomic nervous system

Purpose

The objective of this study is to evaluate the effects of heat and massage application on autonomic nervous system.

Materials and Methods

One hundred thirty-nine subjects volunteered and completed this study. Heat and massage was daily applied for 40 minutes, 5 days a week for 2 weeks. Primary-dependent measures included heart rate variability, sympathetic skin response, and serum cortisol and norepinephrine levels.

Results

Serum cortisol levels were significantly decreased at 2 weeks compared to baseline (p=0.003). Plasma norepinephrine levels at 4 weeks were significantly decreased compared to baseline (p=0.010). Heart rate, using the power spectra, increased significantly after 2 weeks compared to baseline. Of autonomic nerve conduction measures, latency was significantly increased at 2 and 4 weeks compared to baseline (p=0.023, 0.012), and amplitude was significantly decreased at 4 weeks compared to baseline (p=0.008). There were no serious adverse events such as burns or other major complications.

Conclusion

The results of this study suggest that heat and massage applications provide relaxation to the autonomic nervous system without serious adverse events.     

Chronic Caffeine Treatment Prevents Sleep Deprivation-Induced Impairment of Cognitive Function and Synaptic Plasticity

Study Objectives:

This study was undertaken to provide a detailed account of the effect of chronic treatment with a small dose of caffeine on the deleterious effects of sleep loss on brain function in rats.

Experimental Design:

We investigated the effects of chronic (4 weeks) caffeine treatment (0.3 g/L in drinking water) on memory impairment in acutely (24 h) sleep-deprived adult male Wistar rats. Sleep deprivation was induced using the modified multiple platform model. The effects of caffeine on sleep deprivation-induced hippocampus-dependent learning and memory deficits were studied by 3 approaches: learning and memory performance in the radial arm water maze task, electrophysiological recording of early long-term potentiation (E-LTP) in area CA1 of the hippocampus, and levels of memory- and synaptic plasticity-related signaling molecules after E-LTP induction.

Measurement and Results:

The results showed that chronic caffeine treatment prevented impairment of hippocampus-dependent learning, short-term memory and E-LTP of area CA1 in the sleep-deprived rats. In correlation, chronic caffeine treatment prevented sleep deprivation-associated decrease in the levels of phosphorylated calcium/calmodulin-dependent protein kinase II (P-CaMKII) during expression of E-LTP.

Conclusions:

The results suggest that long-term use of a low dose of caffeine prevents impairment of short-term memory and E-LTP in acutely sleep-deprived rats.

Citation:

Alhaider IA; Aleisa AM; Tran TT; Alzoubi KH; Alkadhi KA. Chronic caffeine treatment prevents sleep deprivation-induced impairment of cognitive function and synaptic plasticity. SLEEP 2010;33(4):437-444.     

Pain Sensitivity in Sleepy Pain-Free Normals

Study Objective:

Past studies have shown that acute experimental reduction of time in bed in otherwise healthy, non-sleepy people leads to hyperalgesia. We hypothesized that otherwise healthy, sleepy people may also exhibit hyperalgesia relative to their non-sleepy counterparts.

Design:

Between-groups sleep laboratory study.

Setting:

Hospital-based sleep disorders center.

Participants:

Twenty-seven, healthy, normal participants (age 18–35 years) were recruited and categorized into sleepy and non-sleepy groups based on their average sleep latencies on a screening multiple sleep latency test (MSLT).

Interventions:

Both groups were then allowed 8 hours time in bed, following which they underwent pain sensitivity testing (10:30 and 14:30) and sleepiness assessments by the MSLT (10:00, 12:00, 14:00, and 16:00). Pain sensitivity assessments were made by measuring finger withdrawal latencies to a radiant heat source delivering 5 different heat intensities.

Measurements and Results:

This study showed that after only one night of 8 hours time in bed, the sleepy participants continued to be sleepy and exhibited a more rapid finger withdrawal response (i.e., increased pain sensitivity) to radiant heat than non-sleepy participants.

Conclusion:

This suggests that sleepy individuals experience hyperalgesia in response to a painful stimulus when compared with non-sleepy individuals.

Citation:

Chhangani BS; Roehrs TA; Harris EJ; Hyde M; Drake C; Hudgel DW; Roth T. Pain sensitivity in sleepy pain-free normals. SLEEP 2009;32(8):1011-1017.     

Antidiabetic effects of Corni Fructus extract in streptozotocin-induced diabetic rats

Purpose

Diabetes is the leading cause of end-stage renal failure. The present study was undertaken to characterize the effects of Corni Fructus on diabetic nephropathy in streptozotocin-induced diabetic rats and their mechanisms.

Materials and Methods

Streptozotocin-diabetic rats were orally administrated with Corni Fructus at a dose of 100, 200 or 400 mg/kg body mass for 40 days.

Results

Corni Fructus-treated diabetic rats showed significant decreases of blood glucose, urinary protein levels and water consumption. Corni Fructus also reduced serum total cholesterol, total triglyceride and low-density lipoprotein cholesterol levels, and showed a tendency of enhancing high-density lipoprotein cholesterol level. Levels of serum albumin and creatinine in diabetic rats were also significantly reduced by Corni Fructus administration at a dose of 200 and 400 mg/kg body mass compared with non-treated diabetic rats. Corni Fructus increased catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidose (GSH-px) activities in the kidneys of diabetic rats. Furthermore, Corni Fructus treatment enhanced renal peroxisome proliferator-activated receptor-γ (PPARγ) expression in diabetic rats.

Conclusion

These results demonstrated that Corni Fructus may have the potential to protect the animals from diabetic nephropathy by amelioration of oxidative stress and stimulation of PPARγ expression.     

GABAergic Antagonism of the Central Nucleus of the Amygdala Attenuates Reductions in Rapid Eye Movement Sleep After Inescapable Footshock Stress

Study Objectives:

Rapid eye movement sleep (REM) appears to be especially susceptible to the effects of stress; inescapable footshock stress (IS) can produce reductions in REM that can occur without recovery sleep. The amygdala has well-established roles in stress and emotion; the central nucleus of the amygdala (CNA) projects to REM regulatory regions in the brainstem and has been found to play a key role in the regulation of REM. The objective of this study was to determine whether the reduction in REM induced by IS could be regulated by CNA and brainstem regions.

Design:

The GABAergic agonist muscimol (MUS) and GABAergic antagonist bicuculline (BIC) were microinjected into CNA before IS, and sleep was recorded for 20 h. In a second experiment using the same manipulations, sleep was recorded for 2 h, after which the rats were killed to evaluate Fos expression (a marker of neuronal activity) in the locus coeruleus (LC), a brainstem REM regulatory region.

Setting:

NA.

Patients or Participants:

The subjects were male, outbred Wistar rats.

Interventions:

The rats were surgically implanted with standard electrodes or with telemetry transmitters for determining arousal state.

Measurements and Results:

IS preceded by control or MUS microinjections selectively reduced REM and increased Fos expression in LC. By comparison, microinjection of BIC into CNA prior to IS attenuated both the reduction in REM and Fos expression in LC to levels seen in non-shocked controls.

Conclusions:

The results suggest that the effects of IS on REM may involve local GABAergic inhibition in CNA and activation of LC.

Citation:

Liu X; Yang L; Wellman LL; Tang X; Sanford LD. GABAergic antagonism of the central nucleus of the amygdala attenuates reductions in rapid eye movement sleep after inescapable footshock stress. SLEEP 2009;32(7):888-896.     

Antidiabetic effect of kolaviron,a biflavonoid complex isolated from Garcinia kola seeds,in Wistar rats

Background

Hypoglycaemic effect of kolaviron (KV), (biflavonoid from Garcinia kola) in streptozotocin (STZ)-diabetic rats has been established.

Objectives

To evaluate the possible protective effects of KV on cardiac, renal and hepatic tissues of STZ-diabetic rats.

Methods

This study consists of four groups of 6 rats each. Groups one and two contained non-diabetic and untreated-diabetic rats, respectively. Groups three and four were made up of KV- and glibenclamide (GB) - treated diabetic rats, respectively.

Results

STZ-intoxication caused a significant (p<0.05) increase in the relative weight of liver in diabetic rats. STZ-diabetic rats had significant increase (p<0.05) in the levels of fasting blood glucose (FBG), á-amylase and HbA_1c. A marked and significant (p<0.05) increase in the levels of cardiac, renal and liver marker indices such as serum creatine kinase, lactate dehydrogenase, creatinine, urea and alanine aminotransferase were observed in untreated diabetic rats. Also, untreated diabetic rats had significantly (p<0.05) elevated urinary glucose and protein and, lowered creatinine clearance. In KV- and GB- treated groups, the levels of FBG, á-amylase and HbA_1c were significantly (p<0.05) reduced, while treatment with KV significantly (p<0.05) attenuated the cardiac, renal and liver marker indices.

Conclusion

KV offered significant antidiabetic and tissues protective effects in the rats.     

Heat stress and cardiovascular, hormonal, and heat shock proteins in humans

Context:

Conditions such as osteoarthritis, obesity, and spinal cord injury limit the ability of patients to exercise, preventing them from experiencing many well-documented physiologic stressors. Recent evidence indicates that some of these stressors might derive from exercise-induced body temperature increases.

Objective:

To determine whether whole-body heat stress without exercise triggers cardiovascular, hormonal, and extra-cellular protein responses of exercise.

Design:

Randomized controlled trial.

Setting:

University research laboratory.

Patients or Other Participants:

Twenty-five young, healthy adults (13 men, 12 women; age = 22.1 ± 2.4 years, height = 175.2 ± 11.6 cm, mass = 69.4 ± 14.8 kg, body mass index = 22.6 ± 4.0) volunteered.

Intervention(s):

Participants sat in a heat stress chamber with heat (73°C) and without heat (26°C) stress for 30 minutes on separate days. We obtained blood samples from a subset of 13 participants (7 men, 6 women) before and after exposure to heat stress.

Main Outcome Measure(s):

Extracellular heat shock protein (HSP72) and catecholamine plasma concentration, heart rate, blood pressure, and heat perception.

Results:

After 30 minutes of heat stress, body temperature measured via rectal sensor increased by 0.8°C. Heart rate increased linearly to 131.4 ± 22.4 beats per minute (F_6,24 = 186, P < .001) and systolic and diastolic blood pressure decreased by 16 mm Hg (F_6,24 = 10.1, P < .001) and 5 mm Hg (F_6,24 = 5.4, P < .001), respectively. Norepinephrine (F_1,12 = 12.1, P = .004) and prolactin (F_1,12 = 30.2, P < .001) increased in the plasma (58% and 285%, respectively) (P < .05). The HSP72 (F_1,12 = 44.7, P < .001) level increased with heat stress by 48.7% ± 53.9%. No cardiovascular or blood variables showed changes during the control trials (quiet sitting in the heat chamber with no heat stress), resulting in differences between heat and control trials.

Conclusions:

We found that whole-body heat stress triggers some of the physiologic responses observed with exercise. Future studies are necessary to investigate whether carefully prescribed heat stress constitutes a method to augment or supplement exercise.     

Benzodiazepine Receptor Agonists Cause Drug-Specific and State-Specific Alterations in EEG Power and Acetylcholine Release in Rat Pontine Reticular Formation

Study Objectives:

Benzodiazepine (BDZ) and non-benzodiazepine (NBDZ) hypnotics enhance GABAergic transmission and are widely used for the treatment of insomnia. In the pontine reticular formation (PRF), GABA inhibits rapid eye movement (REM) sleep and acetylcholine (ACh) release. No previous studies have characterized the effects of BDZ and NBDZ hypnotics on ACh release in the PRF. This study tested 2 hypotheses: (1) that microdialysis delivery of zolpidem, eszopiclone, and diazepam to rat PRF alters ACh release in PRF and electroencephalographic (EEG) delta power and (2) that intravenous (IV) administration of eszopiclone to non-anesthetized rat alters ACh release in the PRF, sleep, and EEG delta power.

Design:

A within- and between-groups experimental design.

Setting:

University of Michigan.

Patients or Participants:

Adult male Crl:CD*(SD) (Sprague-Dawley) rats (n = 57).

Interventions:

In vivo microdialysis of the PRF in rats anesthetized with isoflurane was used to derive the concentration-response effects of zolpidem, eszopiclone, and diazepam on ACh release. Chronically instrumented rats were used to quantify the effects of eszopiclone (3 mg/kg, IV) on ACh release in the PRF, sleep-wake states, and cortical EEG power.

Measurements and Results:

ACh release was significantly increased by microdialysis delivery to the PRF of zolpidem and eszopiclone but not diazepam. EEG delta power was increased by zolpidem and diazepam but not by eszopiclone administered to the PRF. Eszopiclone (IV) decreased ACh release in the PRF of both anesthetized and non-anesthetized rats. Eszopiclone (IV) prevented REM sleep and increased EEG delta power.

Conclusion:

The concentration-response data provide the first functional evidence that multiple GABA_A receptor subtypes are present in rat PRF. Intravenously administered eszopiclone prevented REM sleep, decreased ACh release in the PRF, and increased EEG delta power. The effects of eszopiclone are consistent with evidence that ACh release in the PRF is lower during NREM sleep than during REM sleep, and with data showing that cholinergic stimulation of the PRF activates the cortical EEG.

Citation:

Hambrecht-Wiedbusch VS; Gauthier EA; Baghdoyan HA; Lydic R. Benzodiazepine receptor agonists cause drug-specific and state-specific alterations in EEG power and acetylcholine release in rat pontine reticular formation. SLEEP 2010;33(7):909-918.     

Cytoprotective and Antioxidant Effects of the Methanol Extract of Eremomastax Speciosa in Rats

Background

Ethno-botanical information shows that Eremomastax speciosa is used in the traditional management of various stomach complaints including gastro-duodenal ulcers.

Materials and Methods

In this study, we tested the cytoprotective potential of the whole plant methanol extract (100–200 mg/kg, p.o), against HCl/ethanol, absolute ethanol, cold/restraint stress rats, and pylorus legated rats pre-treated with indomethacin. The effects of the extract on gastric lesion inhibition, the volume of gastric juice, gastric pH, gastric acid output, mucus production and gastric peptic activity were recorded. Oxidative stress parameters were measured in blood and gastric tissue samples obtained from the animals in all the models tested.

Results

The extract significantly (p<0.05), reduced the formation of cold/restraint ulcers by (31–60%, inhibition), completely inhibited (100%) the formation of lesions induced by HCl/ethanol at the highest dose, but was less effective against absolute ethanol (22–46% inhibition). The extract (200 mg/kg), significantly reduced lesion formation (P<0.01), gastric acidity (P<0.01), and volume of gastric secretions (P<0.05), in the indomethacin/pylorus ligation model, and did not affect the activity of pepsin in gastric juice. Blood concentrations of antioxidant enzymes (catalase, SOD and GSH), increased significantly and MDA concentrations decreased in all models tested.

Conclusion

Cytoprotection by E. speciosa methanol extract was attributed to its ability to reduce acid secretion, and to enhance mucosal defence and in vivo antioxidant status.     

Antifertility activity of aqueous ethanolic leaf extract of Spondias mombin (Anacardiaceae) in rats

Background

Despite the availability of modern (orthodox) medicine, many developing countries, especially in the rural areas, still rely heavily on traditional healers and medicinal plants to meet their primary health care needs and that of their domestic animals. This has been attributed to easy accessibility and low cost of herbal medicine. In Eastern Nigeria, fresh leaves of Spondias mombin is widely used by the natives to aid delivery and to expel the placenta in small ruminants (sheep and goats), especially during difficult labour.

Objective

The present study was designed to evaluate the in vivo effects of leaf extracts of S. mombin on reproductive performance of female rats.

Methods

Acute toxicity test of the plant extract was carried out in rats of both sexes. The anticonceptive and abortifacient activity of the extract were investigated, including the Fertility Index or embryo score of control and treated animals. The estrogenic activity was determined using ovariectomized rats.

Results

The results revealed a relatively non-toxic plant extract. The extract displayed anticonceptive but not abortifacient activity as judged by the number of pregnant animals at the end of the third trimester of pregnancy. The extract did not exhibit any oestrogenic activity.

Conclusion

Aqueous ethanol leaf extract of S. mombin has significant anticonceptive activity attributed to a direct action of the extract on the uterus.     

Antihyperlipidemic Effect of Peucedanum Pastinacifolium Extract in Streptozotocin-Induced Diabetic Rats

INTRODUCTION:

Dyslipidemia is one of the most common complications of diabetes mellitus, significantly contributing to cardiovascular morbidity and mortality in diabetic patients. Peucedanum pastinacifolium Boiss. & Hausskn. is commonly used as an antihyperlipidemic vegetable in Iranian folk medicine.

MATERIAL AND METHODS:

In this study, we examined a hydroalcoholic extract of the aerial parts of Peucedanum pastinacifolium to determine its lipid-lowering activity in normal and streptozotocin (STZ)-induced diabetic rats. Experimental diabetes mellitus was induced by a single intraperitoneal administration of streptozotocin. Normal and streptozotocin-induced diabetic rats were separated into four groups. The groups were fed with 0, 125, 250 or 500 mg/kg body weight of Peucedanum Pastinacifolium hydroalcoholic Extract (PPE) in aqueous solution for 30 days.

RESULTS:

The results show that there were significant (P < 0.05) increases in total serum cholesterol, triglyceride and low-density lipoprotein cholesterol (LDL-C) and a decrease in high-density lipoprotein cholesterol (HDL-C) in streptozotocin-induced diabetic rats. Treatment of diabetic rats with PPE over a period of a month returned these levels close to control levels.

CONCLUSION:

These results suggest that PPE has hypolipidemic effects in streptozotocin-induced diabetic rats.