Investigation of the Antinociceptive Activity of the Hydroethanolic Extract of Junglas nigra Leaf by the Tail-Immersion and Formalin Pain Tests in Rats.

Background: Juglans (J.) nigra leaf is obtained from a plant that is used in traditional medicine in some countries to alleviate inflammatory diseases. Aim: The aim of this study was to compare the effects of J. nigra extract on acute nociceptive and inflammatory pain in rats. Methods: Antinociceptive activity was examined in Wistar rats by the tail-immersion and formalin tests. Motor function was assessed using the rotarod test. Plant extract was administered intraperitoneally. Results: In the tail-immersion test, the maximal antinociceptive effect of the plant extract (100-330 mg/kg) was about 24-30% and is the result of the effect of a high concentration of ethanol. In the formalin test, the plant extract (41.3-330 mg/kg) significantly and dose-dependently inhibited nociception in both phases of the test with similar maximal effects of about 76% and 85%. Only the plant extract at the dose of 330 mg/kg caused a significant time-dependent reduction in time spent on the rotarod. Conclusions: In rats, the preventive systemic administration of the hydroethanolic extract of J. nigra leaf reduced chemically but not thermally induced pain. Higher efficacy was obtained in pain associated with inflammation and tissue injury. The antinociceptive effect is dose-dependent and may be limited by motor impairment.

Treatment of Peripartum Depression with Antidepressants and Other Psychotropic Medications: A Synthesis of Clinical Practice Guidelines in Europe.

This study examined (1) the availability and content of national CPGs for treatment of peripartum depression, including comorbid anxiety, with antidepressants and other psychotropics across Europe and (2) antidepressant and other psychotropic utilization data as an indicator of prescribers' compliance to the guidelines. We conducted a search using Medline and the Guidelines International Network database, combined with direct e-mail contact with national Riseup-PPD COST ACTION members and researchers within psychiatry. Of the 48 European countries examined, we screened 41 records and included 14 of them for full-text evaluation. After exclusion of ineligible and duplicate records, we included 12 CPGs. Multiple CPGs recommend antidepressant initiation or continuation based on maternal disease severity, non-response to first-line non-pharmacological interventions, and after risk-benefit assessment. Advice on treatment of comorbid anxiety is largely missing or unspecific. Antidepressant dispensing data suggest general prescribers' compliance with the preferred substances of the CPG, although country-specific differences were noted. To conclude, there is an urgent need for harmonized, up-to-date CPGs for pharmacological management of peripartum depression and comorbid anxiety in Europe. The recommendations need to be informed by the latest available evidence so that healthcare providers and women can make informed, evidence-based decisions about treatment choices.

Lithium - Pharmacological and Toxicological Aspects: The Current State of the Art.

Lithium is the smallest monovalent cation with many different biological effects. Although lithium is present in the pharmacotherapy of psychiatric illnesses for decades, its precise mechanism of action is still not clarified. Today lithium represents first-line therapy for bipolar disorders (because it possesses both antimanic and antidepressant properties) and the adjunctive treatment for major depression (due to its antisuicidal effects). Beside, lithium showed some protective effects in neurological diseases including acute neural injury, chronic degenerative conditions, Alzheimer's disease as well as in treating leucopenia, hepatitis and some renal diseases. Recent evidence suggested that lithium also possesses some anticancer properties due to its inhibition of Glycogen Synthase Kinase 3 beta (GSK3ß) which is included in the regulation of a lot of important cellular processes such as: glycogen metabolism, inflammation, immunomodulation, apoptosis, tissue injury, regeneration etc. Although recent evidence suggested a potential utility of lithium in different conditions, its broader use in clinical practice still trails. The reason for this is a narrow therapeutic index of lithium, numerous toxic effects in various organ systems and some clinically relevant interactions with other drugs. Additionally, it is necessary to perform more preclinical as well as clinical studies in order to a precise therapeutic range of lithium, as well as its detailed mechanism of action. The aim of this review is to summarize the current knowledge concerning the pharmacological and toxicological effects of lithium.

Pioglitazone attenuates kidney injury in an experimental model of gentamicin-induced nephrotoxicity in rats.

Gentamicin, belonging to the aminoglycosides, possesses the greatest nephrotoxic effect of all other antibiotics from this group. On the other hand, pioglitazone, which represents peroxisome proliferator-activated receptor γ (PPARγ) agonist recently showed antiinflamatory, antioxidative effects, amelioration of endothelial dysfunction etc. Therefore, the goal of our study was to investigate the effects of pioglitazone on kidney injury in an experimental model of gentamicin-induced nephrotoxicity in rats. These effects were observed by following values of biochemical (serum urea and creatinine) parametars, total histological kidney score, urine level of kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) as well as parametars of oxidative stress (malondialdehyde, superoxide dismutase, catalase, total oxidant status, total antioxidant status, oxidative stress index and advanced oxidation protein products). It seems that pioglitazone protects the injured rat kidney in a U-shaped manner. Medium dose of pioglitazone (1 mg/kg, i.p.) was protective regarding biochemical (serum urea and creatinine), total histological score and the values of kidney injury molecule-1 (KIM-1) (P < 0.05 vs. control group, i.e. rats injected with gentamicin only). This finding could be of great importance for the wider use of aminoglycosides, with therapy that would reduce the occurrence of serious adverse effects, such as nephrotoxicity and acute renal failure.

Preventive treatment with dizocilpine attenuates oedema in a carrageenan model of inflammation: the interaction of glutamatergic and nitrergic signaling.

Dizocilpine is a highly selective and potent non-competitive antagonist of the N-methyl-D-aspartate (NMDA) glutamate receptor. It is well known that dizocilpine has different neuroprotective effects in animal models of pain, epilepsy and oedema during trauma. The search for alternative antiinflammatory drugs is ongoing. We investigated the anti-oedematous effects of dizocilpine and the probable mechanism of action in a rat model that mimics local and persistent inflammation without tissue injury or damage. Male Wistar rats were injected with 100 µL of 0.5% carrageenan to the plantar surface of the hind paw. Anti-oedematous activity was assessed in the carrageenan-induced paw inflammatory oedema test with a plethysmometer. To assess possible mechanisms of dizocilpine action, we examined the effects of the selective inhibitor of neuronal [N-ω-propyl-L-arginine hydrochloride (L-NPA)] and inducible [S-methylisothiourea (SMT)] nitric oxide synthase (NOS). Dizocilpine after systemic (0.0005, 0.005 and 0.02 mg/kg, subcutaneous (s.c.)), but not after local peripheral administration, reduced the paw inflammatory oedema. The effect is not dose dependent, and the highest decrease by about 47% at the time of maximally developed oedema was achieved with 0.005 mg/kg. Intraperitoneally (i.p.) administered L-NPA (0.5, 1 and 2 mg/kg) or SMT (0.005, 0.01 and 0.015 mg/kg) before dizocilpine abolished or reduced the anti-oedematous effect of dizocilpine by about 70-85%. An acute single dose of dizocilpine administered before inducing oedema systemically reduced the development of inflammatory oedema. The mechanism of the anti-oedematous effect includes, at least partially, an increase in nitric oxide (NO) production.

Cannabinoids and Pain: New Insights From Old Molecules.

Cannabis has been used for medicinal purposes for thousands of years. The prohibition of cannabis in the middle of the 20th century has arrested cannabis research. In recent years there is a growing debate about the use of cannabis for medical purposes. The term 'medical cannabis' refers to physician-recommended use of the cannabis plant and its components, called cannabinoids, to treat disease or improve symptoms. Chronic pain is the most commonly cited reason for using medical cannabis. Cannabinoids act via cannabinoid receptors, but they also affect the activities of many other receptors, ion channels and enzymes. Preclinical studies in animals using both pharmacological and genetic approaches have increased our understanding of the mechanisms of cannabinoid-induced analgesia and provided therapeutical strategies for treating pain in humans. The mechanisms of the analgesic effect of cannabinoids include inhibition of the release of neurotransmitters and neuropeptides from presynaptic nerve endings, modulation of postsynaptic neuron excitability, activation of descending inhibitory pain pathways, and reduction of neural inflammation. Recent meta-analyses of clinical trials that have examined the use of medical cannabis in chronic pain present a moderate amount of evidence that cannabis/cannabinoids exhibit analgesic activity, especially in neuropathic pain. The main limitations of these studies are short treatment duration, small numbers of patients, heterogeneous patient populations, examination of different cannabinoids, different doses, the use of different efficacy endpoints, as well as modest observable effects. Adverse effects in the short-term medical use of cannabis are generally mild to moderate, well tolerated and transient. However, there are scant data regarding the long-term safety of medical cannabis use. Larger well-designed studies of longer duration are mandatory to determine the long-term efficacy and long-term safety of cannabis/cannabinoids and to provide definitive answers to physicians and patients regarding the risk and benefits of its use in the treatment of pain. In conclusion, the evidence from current research supports the use of medical cannabis in the treatment of chronic pain in adults. Careful follow-up and monitoring of patients using cannabis/cannabinoids are mandatory.

Inhibition of neuronal nitric oxide synthase attenuate the hypothermic effect of ketamine-magnesium sulfate combination in rats.

Ketamine and magnesium as NMDA receptor antagonists interact synergistically to decrease body temperature in rats. The mechanism of the hypothermic effect of the ketamine-magnesium sulfate combination has not been studied until now. The aim of this study was to examine whether nitric oxide (NO) has a role in the hypothermic effect of ketamine (10 mg/kg) and the combination of ketamine (5 mg/kg) and magnesium sulfate (5 mg/kg). The body temperature was measured by insertion of a thermometer probe 5 cm into the colon of unrestrained male Wistar rats (200-250 g). N(ω)-nitro-L-arginine methyl ester (L-NAME 2.5 and 5 mg/kg) as non-selective inhibitor of nitric oxide synthase at a dose of 5 mg/kg antagonized the effect of the ketamine-magnesium sulfate combination at 60 min (p < 0.05) and 90 min (p < 0.01). Ketamine induced hypothermia was not affected by administrating of L-NAME (2.5 and 5 mg/kg). Inhibitor of inducible nitric oxide synthase N6-(1-Iminoethyl)-L-lysine hydrochloride (L-NIL 1.25 mg/kg and 2.5 mg/kg, sc) did not significantly change the hypothermic response evoked by the ketamine-magnesium sulfate combination. Inhibitor of neuronal nitric oxide synthase N-ω-Propyl-L-arginine hydrochloride (L-NPA) at a dose of 2 mg/kg antagonized the combination at 60 min when it achieved the maximum effect. The NO pathway is not involved in the hypothermic effect of ketamine. Production of NO through neuronal NO synthase, might play a role in the mechanism of the hypothermic effect of the ketamine-magnesium sulfate combination.

Additive and antagonistic antinociceptive interactions between magnesium sulfate and ketamine in the rat formalin test.

Because ketamine and magnesium block NMDA receptor activation by distinct mechanisms of action, we hypothesized that in a model of inflammatory pain in rats the combination of ketamine and magnesium might be more effective than ketamine alone. Antinociceptive activity was assessed by the formalin test in male Wistar rats (200-250 g). Animals were injected with 100 µL of 2.5% formalin to the plantar surface of the right hind paw. Data were recorded as the total time spent in pain-related behavior after the injection of formalin or vehicle (0.9% NaCl). Ketamine and magnesium sulfate given separately reduced nocifensive behavior in the second phase of the formalin test in rats. When ketamine was applied after magnesium sulfate, the log dose-response curves for the effects of ketamine and the magnesium sulfate-ketamine combination revealed antagonistic interaction, and about 1.6 (CL 1.2-2.4) fold increment in ketamine dosage. A low dose of magnesium sulfate (5 mg/kg, subcutaneously) administered after ketamine increased the antinociceptive effect of ketamine by a factor of only 1.2 (CL 0.95-1.38), indicating an additive interaction. There was a 1.8-fold reduction in dosage of ketamine when ketamine was administered before rather than after the magnesium sulfate. The present study revealed that both ketamine and magnesium reduced pain-related behavior in the second phase of the formalin test in rats. Ketamine, when administered before or after the magnesium, provided additive or antagonistic antinociceptive interactions, respectively. Whether there will be an additive or antagonistic antinociceptive interaction between ketamine and magnesium depends on the order of drug administration.

Magnesium in Pain Research: State of the Art.

Magnesium has been shown to produce an antinociceptive effect on animal models of neuropathic and inflammatory pain. It has also been shown to exert an analgesic effect on humans in conditions presenting acute (postoperative pain) and chronic (neuropathic) pain. As it is known that magnesium is a physiological antagonist of the N-methyl-Daspartate (NMDA) receptor ion channel, and that the NMDA receptor plays a key role in central sensitization, the primary mechanism through which magnesium produces its analgesic effect is believed to be blockade of the NMDA receptor in the spinal cord. In addition, magnesium blocks calcium channels and modulates potassium channels. The activation of the nitric oxide (NO) pathway could have an important role in the antinociceptive effects of systemic magnesium sulfate in the somatic, but not in the visceral model of inflammatory pain. Although it is known for some time that intramuscular, intravenous and subcutaneous injections of magnesium sulfate in humans, and intraperitoneal injection in rodents produce local pain sensation, the mechanism of this action was elucidated only recently. It was demonstrated that subcutaneous injection of an isotonic, pHadjusted (7.4) solution of magnesium sulfate (6.2%) to rats produces local peripheral pain via activation of peripheral TRPA1, TRPV1, TRPV4 and NMDA receptors and peripheral production of NO. In animal models of pain, magnesium has been shown to exert both antinociceptive and pronociceptive effects by acting on different ion channels and NO pathways, however, the precise mechanisms remain to be elucidated.

Pharmacotherapy of Pain in the Older Population: The Place of Opioids.

Pain is a common symptom in older people. It is possible that pain is underreported in older persons due to an incorrect belief that it is an inevitable part of aging. Opioid analgesics are potent medications, with confirmed efficacy for the treatment of moderate to severe pain. These drugs are commonly used in older persons. However, there is insufficient evidence regarding safety of opioids in older patients. One of the reasons for this is the lack of randomized, controlled clinical trials. People of advanced age often have comorbidites and use other prescription drugs, as well as over-the-counter (OTC) compounds, thus making them more suceptible to the risk of interactions with opioids. Significant pharmacokinetic and pharmacodynamic changes that occur with advancing age increase the risk of adverse effects of opioids. There are also some discrepancies between guidelines, which recommend the use of lower doses of opioids in older patients, and the findings in the literature which suggest that pain is often undertreated in this age group. It seems that there are significant variations in the tolerability of different opioid analgesics in older people. Morphine, fentanyl, oxycodone, and buprenorphine are still the preferred evidence-based choices for add-on opioid therapy for these patients. However, the safety and efficacy of other opioids in older patients, especially if comorbidities and polypharmacy are present, is still questionable. This review addresses the most important aspects of the use of opioids in older persons, focusing on pharmacokinetics, pharmacodynamics, adverse effects, and interactions.

Evaluation of Novel Biomarkers of Acute Kidney Injury: The Possibilities and Limitations.

Despite the recent findings concerning pathogenesis and novel therapeutic strategies, the mortality rate in patients with acute kidney injury (AKI) remains very high. Early detection of patients with impaired renal function may help to ensure more aggresive treatment and to improve clinical outcome. Serum creatinine is still gold standard of kidney injury, although it is well known as an insensitive and unreliable biomarker (for example, its concentration does not increase significantly until about half of the kidney function is lost). Considering these data, researches and clinicians are making great efforts in the past decade in order to discover and validate novel AKI biomarkers. Kidney injury molecule-1 (KIM-1), Neutrophil gelatinase-associated lipocalin (NGAL), Interleukin-18 (IL-18), Cystatin C (Cys-C) are some of new, promising markers of kidney damage which are currently in the focus of preclinical and clinical studies. Recent data suggest that some of these new biomarkers represent important parametars of acute tubular necrosis (ATN) and reliable predictors of development and prognosis of AKI. Beside that, monitoring of these markers could have significant importance for early diagnosis and clinical course, not only in patients with various forms of AKI and other renal diseases, but also in patients with cardiorenal syndrome, heart failure, cardiopulmonary bypass, cardiothoracical surgical interventions, in the pediatric emergency setting etc. The aim of this review is to summarize the literature data concerning some new biomarkers, evaluate their role as well as their limitations in the early diagnosis and predict clinical outcome of some renal diseases.

Prevention of Renal Complications Induced by Non- Steroidal Anti-Inflammatory Drugs.

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly prescribed for the treatment of pain, inflamation and fever. They are usually well tolerated in healthy persons, but in patients with risk factors (advanced age, renal impairment, heart failure, liver disease, concurrent medications with antihypertensive drugs), NSAIDs can induce serious renal adverse effects. They include sodium and water retention with edema, worsening of heart failure, hypertension, hyponatremia, hyperkalemia, acute kidney injury, chronic kidney disease, renal papillary necrosis and acute interstitial nephritis. The majority of these adverse effects are due to the inhibition of prostaglandins synthesis and they are dose and duration-dependent. Acute forms of kidney injuries are transient and often reversible upon drug withdrawal. Chronic use of NSAIDs in some patients may result in chronic kidney disease. It is recommended that patients at risk should have preventative strategies in place, including the use of the "lowest effective dose" of NSAID for the "shortest possible time" and monitoring renal function, fluid retention and electrolyte abnormalities. Patients who are taking antihypertensive medications should be monitored for high blood pressure and the doses of antihypertensive medications should be adjusted if needed. In general, the combination of NSAIDs and angiotensin inhibitors should be avoided. Some other preventive measures are dietary salt restriction, use of topical NSAIDs/non-pharmacological therapies and use of calcium channel blockers for treating hypertension.

Anti-hyperalgesic effect of systemic magnesium sulfate in carrageenan-induced inflammatory pain in rats: influence of the nitric oxide pathway.

This study investigated whether systemic magnesium sulfate (an antagonist at the glutamate subtype of N-methyl-D-aspartate receptor) affects inflammatory pain, and whether the nitric oxide pathway is involved. Carrageenan (0.5%, 0.1 mL, intraplantar)-induced mechanical hyperalgesia was evaluated using the electronic von Frey test in male Wistar rats. Magnesium sulfate had no effect when injected locally into the inflamed rat paw. However, subcutaneous magnesium sulfate, at doses of 0.5, 5, 15 and 30 mg/kg, reduced the hyperalgesia by 44.4 ± 8.8, 68 ± 8.4, 24.6 ± 6.9 and 45.3 ± 6.7% respectively. N-nitro-L-arginine methyl ester hydrochloride (L-NAME) (3 and 5 mg/kg, intraperitoneal), a non-selective nitric oxide synthase inhibitor, significantly reduced the effects of magnesium sulfate. Also, L-arginine (0.4 mg/kg, subcutaneously) significantly reversed the effect of L-NAME in the magnesium sulfate-treated rats. A selective inhibitor of neuronal or inducible nitric oxide synthase, N-ω-Propyl-L-arginine hydrochloride (L-NPA) (0.5, 1 and 2 mg/kg, intraperitoneal) and S-methylisothiourea (SMT) (0.005, 0.01 and 0.015 mg/kg, intraperitoneal) reduced the effect of magnesium sulfate significantly only at the highest doses tested. When given alone, L-NAME (3 and 5 mg/kg) L-NPA (2 mg/kg) and SMT (0.015 mg/kg) did not have any influence on carrageenan-induced hyperalgesia. The present study revealed that magnesium sulfate is effective against inflammatory pain after systemic, but not after local peripheral administration, and activation of the nitric oxide pathway is probably involved in the anti-hyperalgesic effect of magnesium sulfate. Low doses of systemic magnesium sulfate given as a pretreatment or a treatment might have a beneficial effect in patients with inflammatory somatic pain.