Anti-Inflammatory, Antinociceptive, and Gastric Effects of Hypericum perforatum

The pharmacological activity of Hypericum perforatum was assessed using models of inflammation, nociception, and gastric mucosal injury in rats. H. perforatum was given systemically as well as orally. When administered systemically, H. perforatum (50–300 mg/kg, s.c.) produced a dose-related and significant inhibition of the edematogenic response to s.p. injection of carrageenan. The percentages of maximal inhibition by the above doses were 53.7, 61.3, and 75.3%, respectively (compared to 90% after 50 mg/kg fluoxetine and 60.7% after 72 mg/kg etodolac). In tests of nociception, H. perforatum, administered orally, displayed antinociceptive activity in the tail electric stimulation and hot plate tests. The antinociceptive activity was observed with 25 mg/kg and a maximal increase in hot plate latency by 50% (compared to 73.2 and 77.8% increases by 5 or 10 mg/kg fluoxetine, respectively). In contrast, the acetic acid–induced (0.6%, i.p.) writhing was significantly reduced by fluoxetine or etodolac, but not H. perforatum. Also, the nociceptive response caused by i.p. injection of capsaicin (1.6 μg/paw) was unaffected by H. perforatum, but reduced by fluoxetine. Injection of H. perforatum (50, 125, or 250 mg/kg, s.c.) to pylorus-ligated rats, decreased gastric acid secretion, but increased indomethacin-induced gastric mucosal lesions dose dependently. These results demonstrate that H. perforatum exhibits antiedematogenic and antinociceptive properties, which may be of value for the management of inflammatory painful conditions. The agent, however, causes gastric irritation and may aggravate that of NSAIDs

Inhibition of Gastric Acid Secretion by Unfractionated and Low Molecular Weight Heparins in the Rat

The majority of patients receiving heparin preparations are at stress, which is a risk factor for the development of gastric erosions. Our aim was to examine the effect of unfractionated heparin (UFH) and low molecular weight heparins (LMWHs) on gastric acid secretion. Gastric acid secretion was induced in urethane-anesthetized rats by distention of the stomach (2 ml saline for 2 h) in addition to histamine or bethanechol stimulation. Distension-stimulated acid secretion (2 ml for 2 h) was significantly inhibited by intraperitoneal administration of UFH (2000 IU/kg, 19% reduction), enoxaparin (180 or 360 IU/kg, 59.2 and 87.1%, reduction, respectively), nadroparin (1000 or 2000 IU/kg, 36 and 60.7% reduction, respectively), and tinzaparin (3000 IU/kg, 41.3% reduction). All tested heparins also suppressed acid secretion in response to distention and histamine or bethanechol stimulation. Pretreatment with indomethacin did not abolish the gastric inhibitory action of nadroparin. After truncal vagotomy or atropine, nadroparin failed to inhibit acid secretion stimulated by histamine. Ganglionic blockade with guanethidine abolished the gastric inhibitory action of nadroparin or UFH. It is concluded that both UFH and LMWHs administered peripherally inhibit stimulated gastric acid secretion in the rat. This effect of heparins is determined by cholinergic and partly by adrenergic mechanisms

Effect of spironolactone on pain responses in mice

The effects of spironolactone, a non-selective aldosterone antagonist, were examined on thermally-induced pain using the hot-plate and tail-flick tests, on hemogenic pain induced by intraplantar capsaicin, on electrically-induced pain, on visceral nociception induced by intraperitoneal acetic acid injection and on haloperidol-induced catalepsy in mice. Spironolactone significantly shortened response latency in the mouse tail-flick test but produced modest decreases in response latencies in the mouse hot plate test. The drug reduced the antinociceptive effect of tramadol in the hot plate test. Spironolactone in addition decreased nociceptive thresholds of electrically-induced pain in mice. In contrast, spironolactone elicited significant antinociceptive actions in the mouse acetic-acid-induced writhing assay and at doses of 20-160 mg/kg decreased capsaicin-induced chemogenic pain. Spironolactone at doses of 40 or 80 mg/kg reduced spontaneous activity and produced a significant impairment on the rotarod test in mice. The drug (10-80 mg/kg) increased the duration of catalepsy induced by haloperidol by 56.3-188.5 %. In conclusion, spironolactone increased pain behavior in a dosedependent manner in models of thermal and electrical pain, but decreased inflammatory visceral pain due to intraperitoneal acetic acid and chemogenic pain due to intraplantar capsaicin. The effect of spironolactone on various types of pain needs further evaluation

Neuroprotective effect of nitric oxide donor isosorbide-dinitrate against oxidative stress induced by ethidium bromide in rat brain

This study investigated the effect of systemic administration of isosorbide-dinitrate (ISDN) on oxidative stress and brain monoamines in a toxic model of brain demyelination evoked by intracerebral injection (i.c.i) of ethidium bromide (10 μl of 0.1 %). Rats received saline (control) or ISDN at 5 or 10 mg/kg for 10 days prior to injection of ethidium bromide. Rats were euthanized one day later, and then the levels of reduced glutathione (GSH), lipid peroxidation (malondialdehyde; MDA), nitric oxide (nitrite/nitrate), acetylcholinesterase (AChE) activity, paraoxonase activity as well as monoamine levels (serotonin, dopamine and noradrenaline) were assessed in the brain cortex in different treatment groups. The i.c.i of ethidium bromide resulted in increased oxidative stress in the cortex one day after its injection; (i) MDA increased by 36.9 %; (ii) GSH decreased by 20.8 %, while (iii) nitric oxide increased by 60.3 %; (iv) AChE and paraoxonase activities in cortex decreased by 35.9 % and 29.4 %, respectively; (v) serotonin was significantly increased. In ethidium bromide-treated rats, pretreatment with ISDN at 10 mg/kg decreased cortical MDA by 23.9 %. Reduced glutathione was increased by 25.1 % ISDN at 10 mg/kg, while nitric oxide showed a 32.8 and 41.7 % decrease after 5 and 10 mg/kg of ISDN, respectively. Acetylcholinesterase activity increased by 24.3 % by 10 mg/kg of ISDN. Paraoxonase activity showed further decrease by 72.2 and 83.8 % after treatment with 5 and 10 mg/kg of ISDN, respectively. The administration of ISDN decreased the level of serotonin and noradrenaline compared with the ethidium bromide only treated group. Overall, the present findings suggest neuroprotective effect of ISDN against oxidative stress in this model of chemical demyelination

The effect of different antidepressant drugs of oxidative stress after lipopolysaccharide administration in mice

This study investigated the effect of the serotonin selective reuptake inhibitors (SSRIs) fluoxetine, sertraline, fluvoxamine and the tricyclic antidepressant (TCA) impiramine on oxi-dative stress in brain and liver induced by lipopolysaccharide administration in mice. Each drug was administered subcutaneously at doses of 10 or 20 mg/kg, for two days prior to in-traperitoneal (i.p.) administration of lipopolysaccharide E (LPS: 200 μg/kg). Mice were euthanized 4 h after administration of the lipopolysaccharide. Lipid peroxidation (malondial-dehyde; MDA), reduced glutathione (GSH) and nitric oxide (nitrite/nitrate) concentrations were measured in brain and liver. Results: The administration of lipopolysaccharide increased oxidative stress in brain and liv-er; it increased brain MDA by 36.1 and liver MDA by 159.8 %. GSH decreased by 34.1 % and 64.8 % and nitric oxide increased by 78.7 % and 103.8 % in brain and liver, respectively. In brain, MDA decreased after the administration of sertraline and by the lower dose of fluo-xetine or fluvoxamine, but increased after the higher dose of imipramine. Reduced glutathione increased after sertraline, fluvoxamine and the lower dose of fluoxetine or imipramine. Nitric oxide decreased by sertraline, fluoxetine, fluvoxamine and by the lower dose of imipramine. In the liver, all drugs decreased MDA and increased GSH level. Nitric oxide is decreased by sertraline, fluvoxamine and by the lower dose of fluoxetine or imipramine. It is concluded that, during mild systemic inflammatory illness induced by peripheral bacterial endotoxin in-jection, the SSRIs fluoxetine, sertraline and fluvoxamine reduced, while the TCA impiramine increased oxidative stress induced in the brain. The SSRIs as well as imipramine reduced oxi-dative stress due to lipopolysaccharide in liver tissue

The effects of trimetazidine on lipopolysaccharide-induced oxidative stress in mice

The effects of trimetazidine, a novel anti-ischemic agent, on the development of oxidative stress induced in mice with lipopolysaccharide endotoxin were investigated. The drug was administered orally once daily at doses of 1.8, 3.6 or 7.2 mg/kg for two days prior to intraperitoneal (i.p.) injection of lipopolysaccharide E (200 μg/kg) and at time of endotoxin administration. Mice were euthanized 4 h after administration of the lipopolysaccharide. Lipid peroxidation (malondialdehyde; MDA), reduced glutathione (GSH) and nitric oxide (nitrite/nitrate) concentrations were measured in brain and liver. The administration of lipopolysaccharide increased oxidative stress in both the brain and liver tissue. MDA increased by 33.9 and 107.1 %, GSH decreased by 23.9 and 84.3 % and nitric oxide increased 70.3 and 48.4 % in the brain and liver, respectively. Compared with the lipopolysaccharide control group, brain MDA decreased by 26.2 and 36.7 %, while GSH increased by 18.2 and 25.8 % after the administration of trimetazidine at 3.6 and 7.2 mg/kg, respectively. Brain nitric oxide decreased by 45.3, 50.8 and 57.0 % by trimetazidine at 1.8, 3.6 and 7.2 mg/kg, respectively. In the liver, MDA decreased by 18.7, 30.7 and 49.4 % and GSH increased by 150.3, 204.8 and 335.4 % following trimetazidine administration at 1.8, 3.6 and 7.2 mg/kg. Meanwhile, nitric oxide decreased by 17.3 % by 7.2 mg/kg of trimetazidine. These results indicate that administration of trimetazidine in the presence of mild systemic inflammatory response alleviates oxidative stress in the brain and liver

Effects of Cannabis sativa extract on haloperidol-induced catalepsy and oxidative stress in the mice

Haloperidol is a classic antipsychotic drug known for its propensity to cause extrapyramidal symptoms due to blockade of dopamine D2 receptors in the striatum. Interest in medicinal uses of cannabis is growing. Cannabis sativa has been suggested as a possible adjunctive in treatment of Parkinson's disease. The present study aimed to investigate the effect of repeated administration of an extract of Cannabis sativa on catalepsy and brain oxidative stress induced by haloperidol administration in mice. Cannabis extract was given by subcutaneous route at 5, 10 or 20 mg/kg (expressed as Δ9-tetrahydrocannabinol) once daily for 18 days and the effect on haloperidol (1 mg/kg, i.p.)-induced catalepsy was examined at selected time intervals using the bar test. Mice were euthanized 18 days after starting cannabis injection when biochemical assays were carried out. Malondialdehyde (MDA), reduced glutathione (GSH) and nitric oxide (the concentrations of nitrite/nitrate) were determined in brain and liver. In saline-treated mice, no catalepsy was observed at doses of cannabis up to 20 mg/kg. Mice treated with haloperidol at the dose of 1 mg/kg, exhibited significant cataleptic response. Mice treated with cannabis and haloperidol showed significant decrease in catalepsy duration, compared with the haloperidol only treated group. This decrease in catalepsy duration was evident on days 1-12 after starting cannabis injection. Later the effect of cannabis was not ap-parent. The administration of only cannabis (10 or 20 mg/kg) decreased brain MDA by 17.5 and 21.8 %, respectively. The level of nitric oxide decreased by 18 % after cannabis at 20 mg/kg. Glucose in brain decreased by 20.1 % after 20 mg/kg of cannabis extract. The administration of only haloperidol increased MDA (22.2 %), decreased GSH (25.7 %) and increased brain nitric oxide by 44.1 %. The administration of cannabis (10 or 20 mg/kg) to haloperidol-treated mice resulted in a significant decrease in brain MDA and nitric oxide as well as a significant increase in GSH and glucose compared with the haloperidol-control group. Cannabis had no significant effects on liver MDA, GSH, nitric oxide in saline or haloperidol-treated mice. It is concluded that cannabis improves catalepsy induced by haloperidol though the effect is not maintained on repeated cannabis administration. Cannabis alters the oxidative status of the brain in favor of reducing lipid peroxidation, but reduces brain glucose, which would impair brain energetics

Amelioration of the haloperidol-induced memory impairment and brain oxidative stress by cinnarizine

Haloperidol is a classic antipsychotic drug known for its propensity to cause extrapyramidal symptoms and impaired memory, owing to blockade of striatal dopamine D2 receptors. Cinnarizine is a calcium channel blocker with D2 receptor blocking properties which is widely used in treatment of vertiginous disorders. The present study aimed to see whether cinnarizine would worsen the effect of haloperidol on memory function and on oxidative stress in mice brain. Cinnarizine (5, 10 or 20 mg/kg), haloperidol, or haloperidol combined with cinnarizine was administered daily via the subcutaneous route and mice were examined on weekly basis for their ability to locate a submerged plate in the water maze test. Mice were euthanized 30 days after starting drug injection. Malondialdehyde (MDA), reduced glutathione (GSH) and nitric oxide (nitrite/nitrate) were determined in brain. Haloperidol substantially impaired water maze performance. The mean time taken to find the escape platform (latency) was significantly delayed by haloperidol (2 mg/kg, i.p.) on weeks 1-8 of the test, compared with saline control group. In contrast, those treated with haloperidol and cinnarizine showed significantly shorter latencies, which indicated that learning had occurred immediately. Haloperidol resulted in increased MDA in cortex, striatum, cerebellum and midbrain. GSH decreased in cortex, striatum and cerebellum and nitric oxide increased in cortex. Meanwhile, treatment with cinnarizine (20 mg/kg) and haloperidol resulted in significant decrease in MDA cortex, striatum, cerebellum and midbrain and an increase in GSH in cortex and striatum, compared with haloperidol group. These data suggest that cinnarizine improves the haloperidol induced brain oxidative stress and impairment of learning and memory in the water maze test in mice

Cannabis-induced impairment of learning and memory

Cannabis sativa preparations are the most commonly used illicit drugs worldwide. The present study aimed to investigate the effect of Cannabis sativa extract in the working memory version of the Morris water maze (MWM; Morris, 1984) test and determine the effect of standard memory enhancing drugs. Cannabis sativa was given at doses of 5, 10 or 20 mg/kg (expressed as Δ^9-tetrahydrocannabinol) alone or co-administered with donepezil (1 mg/kg), piracetam (150 mg/ kg), vinpocetine (1.5 mg/kg) or ginkgo biloba (25 mg/kg) once daily subcutaneously (s.c.) for one month. Mice were examined three times weekly for their ability to locate a submerged platform. Mice were euthanized 30 days after starting cannabis injection when biochemical assays were carried out. Malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide, glucose and brain monoamines were determined. Cannabis resulted in a significant increase in the time taken to locate the platform and enhanced the memory impairment produced by scopolamine. This effect of cannabis decreased by memory enhancing drugs with piracetam resulting in the most-shorter latency compared with the cannabis. Biochemically, cannabis altered the oxidative status of the brain with decreased MDA, increased GSH, but decreased nitric oxide and glucose. In cannabis-treated rats, the level of GSH in brain was increased after vinpocetine and donepezil and was markedly elevated after Ginkgo biloba. Piracetam restored the decrease in glucose and nitric oxide by cannabis. Cannabis caused dose-dependent increases of brain serotonin, noradrenaline and dopamine. After cannabis treatment, noradrenaline is restored to its normal value by donepezil, vinpocetine or Ginkgo biloba, but increased by piracetam. The level of dopamine was significantly reduced by piracetam, vinpocetine or Ginkgo biloba. These data indicate that cannabis administration is associated with impaired memory performance which is likely to involve decreased brain glucose availability as well as alterations in brain monoamine neurotransmitter levels. Piracetam is more effective in ameliorating the cognitive impairments than other nootropics by alleviating the alterations in glucose, nitric oxide and dopamine in brain