ABSTRACT
Previous studies show ATP-sensitive potassium (KATP) channel openers can reduce hypersensitivity associated with chronic pain models in rodents, and reduce morphine tolerance. Many agonists of KATP channels are not soluble in physiologically relevant vehicles, requiring adaptation for clinical use. This study compared the antinociceptive activity of novel KATP channel targeting prodrugs, CKLP1, CKLP2, and CF3-CKLP. These prodrugs are activated by endogenous alkaline phosphatase enzymes present in the peripheral and central nervous systems. Analgesic capabilities of intrathecally injected prodrugs were tested in rodent models of spinal nerve ligation (SNL) and complete Freund's adjuvant (CFA) as models for neuropathic and inflammatory pain, respectively. CKLP1 and CKLP2 significantly increased mechanical paw withdrawal thresholds 1-2 hours after intrathecal administration in the SNL model, but all three prodrugs were able to attenuate hypersensitivity up to 7 days after CFA treatment. The reduction of opioid tolerance and opioid-induced hypersensitivity in mice treated chronically with morphine was significantly reduced in CKLP1 and CKLP2 treated animals. Prodrug cleavage was confirmed in mouse spinal cords using liquid chromatography. These studies may aid in the further development of KATP channel prodrugs for use in treatments of chronic pain, opioid tolerance, and withdrawal. SIGNIFICANCE STATEMENT: The cromakalim prodrugs, CKLP1, CKLP2, and CF3-CKLP1 reduced hypersensitivity in inflammatory and neuropathic pain models in male and female mice. CKLP1 and CKLP2 also reduced morphine-induced hypersensitivity in a mouse model of chronic morphine exposure. CKLP2 reduced jumping and rearing behaviors after naloxone-induced precipitated morphine withdrawal. Taken together, CKLP2 demonstrates the potential for development as a non-opioid analgesic drug.
Subject(s)
Chronic Pain , Hypersensitivity , Neuralgia , Prodrugs , Mice , Male , Female , Animals , Morphine/pharmacology , Morphine/therapeutic use , Prodrugs/pharmacology , Prodrugs/therapeutic use , Analgesics, Opioid/pharmacology , Analgesics, Opioid/therapeutic use , Drug Tolerance/physiology , Neuralgia/chemically induced , Neuralgia/drug therapy , Adenosine TriphosphateABSTRACT
AIM: To evaluate the long-term effectiveness of cannabidiol (CBD)-enriched oil for the treatment of refractory epilepsy and to assess the development of tolerance to its anti-seizure effect. METHODS: A prospective study of 92 consecutive patients (age 1-37 years, mean-11.8 years) with treatment resistant epilepsy who were treated with cannabis oil extract (CBD/tetrahydrocannabinol [THC] ratio of 20:1). Mean monthly seizure frequency was reported by the patients/their parents during monthly clinic visits. Tolerance was defined as either the need to increase the dose by ≥30% due to reduced treatment efficacy or as an increase of ≥30% in mean monthly seizure frequency in patients treated for at least 3 months with no change in other anti-seizure medications. RESULTS: Mean follow-up time was 19.8 ± 12.5 months (range 3-45). Mean CBD dose was 11.3 (4-38) mg/kg/day. Twenty-nine (31%) patients discontinued treatment due to lack of effect or adverse reactions, which were reported in 51% (47/87) of the patients. Overall responder rate (>50% seizures reduction) was 54%, whereas 8 patients (9%) became seizure-free. Eighty-four patients were included in the tolerance analysis. Tolerance was observed in 21 (25%) patients after a mean duration of 7.3 ± 5.4 months of CBD-enriched oil treatment. There was a negative correlation between epilepsy duration and tolerance development (p = 0.038). CONCLUSIONS: We report for the first time the plausible appearance of tolerance to cannabidiol-enriched oil. This may limit treatment efficacy in the long-term clinical management of refractory epilepsy in both pediatric and adult population. Further studies are needed to investigate potential mechanisms.
Subject(s)
Cannabidiol/therapeutic use , Drug Resistant Epilepsy/drug therapy , Drug Tolerance/physiology , Adolescent , Adult , Anticonvulsants/therapeutic use , Cannabidiol/metabolism , Child , Child, Preschool , Drug Resistant Epilepsy/metabolism , Epilepsy/drug therapy , Epilepsy/metabolism , Female , Humans , Infant , Israel , Male , Prospective Studies , Seizures/drug therapy , Seizures/metabolism , Treatment OutcomeABSTRACT
Embedded in an extracellular matrix, biofilm-residing bacteria are protected from diverse physicochemical insults. In accordance, in the human host the general recalcitrance of biofilm-grown bacteria hinders successful eradication of chronic, biofilm-associated infections. In this study, we demonstrate that upon addition of promethazine, an FDA approved drug, antibiotic tolerance of in vitro biofilm-grown bacteria can be abolished. We show that following the addition of promethazine, diverse antibiotics are capable of efficiently killing biofilm-residing cells at minimal inhibitory concentrations. Synergistic effects could also be observed in a murine in vivo model system. PMZ was shown to increase membrane potential and interfere with bacterial respiration. Of note, antibiotic killing activity was elevated when PMZ was added to cells grown under environmental conditions that induce low intracellular proton levels. Our results imply that biofilm-grown bacteria avoid antibiotic killing and become tolerant by counteracting intracellular alkalization through the adaptation of metabolic and transport functions. Abrogation of antibiotic tolerance by interfering with the cell's bioenergetics promises to pave the way for successful eradication of biofilm-associated infections. Repurposing promethazine as a biofilm-sensitizing drug has the potential to accelerate the introduction of new treatments for recalcitrant, biofilm-associated infections into the clinic.
Subject(s)
Biofilms/drug effects , Energy Metabolism/drug effects , Promethazine/pharmacology , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/physiology , Animals , Drug Tolerance/physiology , Humans , Mice , Mice, Inbred BALB C , Pseudomonas InfectionsABSTRACT
OBJECTIVE: To evaluate the effects of Zhumeria majdae essential oil (ZMEO) on morphine dependence and tolerance in mice. METHODS: ZMEO (10, 20, and 40 mg/kg) and clonidine (0.1 mg/kg) as the positive control were injected intraperitoneally (i.p.). The effect of ZMEO and clonidine on the dependence were evaluated by counting the number of jumps induced by naloxone (5 mg/kg) while the tolerance was evaluated by the tail-flick test. RESULTS: ZMEO at the dose of 10 mg/kg during the development period led to a significant inhibition of morphine tolerance (P<0.01), while it led to reduced morphine dependence with the doses of 20 and 40 mg/kg. ZMEO at two dose levels of 20 and 40 mg/kg indicated significant antinociceptive activity (P>0.01), and significantly reduced the withdrawal signs (number of jumps) of mice (P>0.01). CONCLUSIONS: ZMEO had significant effects on morphine tolerance and dependence. The linalool rich essential oil of Z. majdae plays a major role in the reduction of tolerance and dependence induced by morphine.
Subject(s)
Drug Tolerance , Lamiaceae/chemistry , Morphine Dependence , Morphine , Plant Oils/pharmacology , Animals , Drug Tolerance/physiology , Mice , Morphine Dependence/drug therapy , Morphine Dependence/pathology , Oils, Volatile/pharmacology , Oils, Volatile/therapeutic use , Pain/drug therapy , Pain Perception/drug effects , Plant Oils/therapeutic useABSTRACT
Chronic pain is the most common reason reported for using medical cannabis. The goal of this research was to determine whether the two primary phytocannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), are effective treatments for persistent inflammatory pain. In experiment 1, inflammation was induced by intraplantar injection of Complete Freund's adjuvant (CFA). Then THC (0.0-4.0 mg/kg, i.p.) or CBD (0.0-10 mg/kg, i.p.) was administered twice daily for 3 days. On day 4, THC, CBD, or vehicle was administered, and allodynia, hyperalgesia, weight-bearing, locomotor activity, and hindpaw edema were assessed 0.5-4 hours postinjection. In experiment 2, CFA or mineral oil (no-pain control)-treated rats were given THC (2.0 mg/kg, i.p.), CBD (10 mg/kg, i.p.), or vehicle in the same manner as in experiment 1. Four hours postinjection on day 4, serum samples were taken for analysis of cytokines known to influence inflammatory pain: interleukin (IL)-1ß, IL-6, IL-10, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α THC dose-dependently reduced pain-related behaviors but did not reduce hindpaw edema, and little tolerance developed to THC's effects. In contrast, CBD effects on inflammatory pain were minimal. THC produced little to no change in serum cytokines, whereas CBD decreased IL-1ß, IL-10, and IFN-γ and increased IL-6. Few sex differences in antinociception or immune modulation were observed with either drug, but CFA-induced immune activation was significantly greater in males than females. These results suggest that THC may be more beneficial than CBD for reducing inflammatory pain in that THC maintains its efficacy with short-term treatment in both sexes and does not induce immune activation. SIGNIFICANCE STATEMENT: The pain-relieving effects of cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) are examined in male and female rats with persistent inflammatory pain to determine whether individual phytocannabinoids could be a viable treatment for men and women with chronic inflammatory pain. Additionally, sex differences in the immune response to an adjuvant and to THC and CBD are characterized to provide preliminary insight into immune-related effects of cannabinoid-based therapy for pain.
Subject(s)
Analgesics/pharmacology , Cannabidiol/pharmacology , Cannabinol/pharmacology , Chronic Pain/drug therapy , Chronic Pain/etiology , Inflammation/complications , Animals , Chronic Pain/metabolism , Cytokines/metabolism , Dose-Response Relationship, Drug , Drug Tolerance/physiology , Female , Inflammation/metabolism , Male , Rats , Rats, Sprague-Dawley , Sex CharacteristicsABSTRACT
OBJECTIVES: To investigate whether mice develop tolerance to the anxiolytic-like and anticonvulsant effects of subchronic treatment with EA (the styryl-2-pyrones and dihydrostyryl-2-pyrones-rich fraction of Polygala sabulosa), as well as any withdrawal symptoms after abrupt discontinuation; to compare the effects of EA with those of diazepam (DZP) on withdrawal-induced anxiety; and to evaluate the toxicity of EA according to OECD guidelines. METHODS: Male or female mice were acutely or subchronically treated with EA or DZP, and their tolerance to anxiolytic (evaluated in the elevated plus maze, EPM) and anticonvulsant effects (measured against pentylenetetrazole (PTZ)-induced convulsions) were investigated. Other groups received EA or DZP for 28 days followed by withdrawal, being the anxiety-like behaviour evaluated in the EPM. KEY FINDINGS: Both acute and subchronic treatments with EA induced an anxiolytic effect in the EPM. The anticonvulsant activity of DZP, but not EA, was reduced by protracted treatment. EA withdrawal retained the anxiolytic profile, while DZP withdrawal induced anxiogenesis. EA counteracted the anxiogenic-like actions of DZP withdrawal. EA has low toxicity as it did not cause any changes in the biochemical, haematological and histopathological markers. CONCLUSIONS: EA avoids the development of tolerance to its anxiolytic-like and anticonvulsant actions, and does not promote withdrawal syndrome. EA does not cause relevant toxic effects in rodents.
Subject(s)
Anti-Anxiety Agents/pharmacology , Anticonvulsants/pharmacology , Plant Extracts/pharmacology , Polygala , Pyrones/pharmacology , Substance Withdrawal Syndrome , Animals , Anti-Anxiety Agents/isolation & purification , Anticonvulsants/isolation & purification , Drug Tolerance/physiology , Female , Male , Mice , Plant Extracts/isolation & purification , Psychopharmacology , Pyrones/isolation & purificationABSTRACT
In an 8-week randomized trial of patients with mild or moderate hypertension, the authors investigated the efficacy and tolerability of initial high (5.0 mg/d) vs low (2.5 mg/d) doses of S-(-)-amlodipine (equivalent to 5 and 10 mg of racemic amlodipine, respectively). In the S-(-)-amlodipine 2.5-mg group (n=263), 24-hour ambulatory systolic/diastolic blood pressure (±standard deviation) decreased from 131.5±15.0/82.1±10.7 mm Hg at baseline to 126.0±13.5/78.5±9.5 mm Hg at 8 weeks of follow-up by a least square mean (±standard error) change of 6.0±0.6/3.8±0.4 mm Hg. In the S-(-)-amlodipine 5-mg group (n=260), the corresponding changes were from 133.6±13.7/83.1±9.9 mm Hg to 125.0±12.0/78.2±8.9 mm Hg by 8.1±0.6/4.7±0.4 mm Hg, respectively. The between-group differences in changes in 24-hour systolic/diastolic blood pressure were 2.1/0.9 (P=.02/.17) mm Hg. Similar trends were observed for daytime and nighttime ambulatory and clinic blood pressure. The incidence rate was similar for all adverse events. An initial high dose of S-(-)-amlodipine improved ambulatory blood pressure control with similar tolerability as an initial low dose in hypertension.
Subject(s)
Amlodipine/pharmacology , Blood Pressure Monitoring, Ambulatory/methods , Drug Tolerance/physiology , Hypertension/drug therapy , Aged , Amlodipine/administration & dosage , Antihypertensive Agents/therapeutic use , Blood Pressure/drug effects , Calcium Channel Blockers/therapeutic use , Dose-Response Relationship, Drug , Female , Humans , Male , Middle Aged , Treatment OutcomeABSTRACT
Panax ginseng is an important cash crop in the Asian countries due to its pharmaceutical effects, however the plant is exposed to various abiotic stresses, lead to reduction of its quality. One of them is the Aluminum (Al) accumulation. Plant growth promoting bacteria which able to tolerate heavy metals has been considered as a new trend for supporting the growth of many crops in heavy metal occupied areas. In this study, twelve bacteria strains were isolated from rhizosphere of diseased Korean ginseng roots located in Gochang province, Republic of Korea and tested for their ability to grow in Al-embedded broth media. Out of them, four strains (Pseudomonas simiae N3, Pseudomonas fragi N8, Chryseobacterium polytrichastri N10, and Burkholderia ginsengiterrae N11-2) were able to grow. The strains could also show other plant growth promoting activities e.g. auxins and siderophores production and phosphate solubilization. P. simiae N3, C. polytrichastri N10, and B. ginsengiterrae N11-2 strains were able to support the growth of Arabidopsis thaliana stressed by Al while P. fragi N8 could not. Plants inoculated with P. simiae N3, C. polytrichastri N10, and B. ginsengiterrae N11-2 showed higher expression level of Al-stress related genes, AtAIP, AtALS3 and AtALMT1, compared to non-bacterized plants. Expression profiles of the genes reveal the induction of external mechanism of Al resistance by P. simiae N3 and B. ginsengiterrae N11-2 and internal mechanism by C. polytrichastri N10. Korean ginseng seedlings treated with these strains showed higher biomass, particularly the foliar part, higher chlorophyll content than non-bacterized Al-stressed seedlings. According to the present results, these strains can be used in the future for the cultivation of ginseng in Al-persisted locations.
Subject(s)
Aluminum/pharmacology , Arabidopsis/drug effects , Arabidopsis/genetics , Arabidopsis/microbiology , Bacteria/metabolism , Drug Tolerance/physiology , Plant Development/drug effects , Stress, Physiological/drug effects , Aluminum/metabolism , Bacteria/classification , Bacteria/genetics , Bacteria/isolation & purification , Biomass , Chlorophyll/analysis , DNA, Bacterial/genetics , Drug Resistance, Bacterial/genetics , Drug Resistance, Bacterial/physiology , Gene Expression Regulation, Plant/drug effects , Gene Expression Regulation, Plant/genetics , Genes, Bacterial , Indoleacetic Acids/metabolism , Metals, Heavy/metabolism , Panax/drug effects , Plant Leaves/metabolism , Plant Roots/chemistry , Plant Roots/microbiology , RNA, Ribosomal, 16S/genetics , Republic of Korea , Rhizosphere , Seedlings/drug effects , Seedlings/growth & development , Siderophores/metabolism , Soil Microbiology , Stress, Physiological/geneticsABSTRACT
BACKGROUND: Transcutaneous electrical nerve stimulation (TENS) is a treatment commonly used for managing pain; however, the ideal placement of the electrodes is not fully understood. OBJECTIVE: To investigate the best way to apply TENS electrodes in an experimental inflammatory pain model. METHOD: Knee joint inflammation was induced in rats, followed by administration of low-frequency TENS (4Hz) under anesthesia for five days. Animals were randomly allocated to five groups according to electrode placement (n=6, each): dermatome, contralateral, paraspinal, acupoint, and control. INTERVENTIONS: Low-frequency TENS at sensory intensity and 100µs pulse duration. Withdrawal thresholds to mechanical (von Frey) and thermal stimuli and joint edema were assessed before induction of inflammation and immediately before and after application of TENS. RESULTS: Reduced paw withdrawal threshold and thermal latency that occur 24h after the induction of inflammation were significantly reversed by the administration of TENS in all groups when compared with sham treatment or with the condition before TENS treatment. No difference was observed in the edema measurement. CONCLUSION: These results offer more options for practitioners to choose the area of the body most commodious for electrode placement, depending on the clinical condition of the patient, because the effect was similar at all sites. In addition, there was a loss of the effectiveness of TENS in reversing mechanical and thermal hyperalgesia on the fifth day, suggesting the development of the tolerance phenomenon.
Subject(s)
Drug Tolerance/physiology , Hyperalgesia/physiopathology , Inflammation/physiopathology , Knee Joint/physiopathology , Transcutaneous Electric Nerve Stimulation , Animals , Electrodes , Humans , Pain Management , Rats , Transcutaneous Electric Nerve Stimulation/methodsABSTRACT
Introducción. El ictus es una causa principal de mortalidad y discapacidad. El policosanol ha sido efi caz en modelos de isquemia cerebral. Este estudio investiga si el tratamiento a largo plazo con policosanol, añadido a la terapia con ácido acetilsalicílico (AAS), dentro de los 30 días posteriores a un ictus, es mejor que el placebo + AAS en la recuperación de los pacientes. Pacientes y métodos. Estudio aleatorizado, doble ciego, controlado con placebo. Se incluyeron 80 pacientes (edad media: 69 años) que sufrieron un ictus en los 30 días previos y con una puntuación de 2-4 en la escala de Rankin modifi cada(mRS). Se distribuyeron aleatoriamente en dos grupos y recibieron policosanol + AAS o placebo + AAS durante 12 meses. Resultados. El tratamiento con policosanol + AAS disminuyó signifi cativamente la puntuación en la mRS desde el primer control intermedio (1,5 meses). El efecto del tratamiento incluso mejoró con la terapia a largo plazo. El número de pacientes que alcanzaron valores de mRS menores o iguales a 1 fue superior en el grupo de policosanol + AAS (87,5%) que en el de placebo + AAS (0%). El tratamiento con policosanol + AAS aumentó signifi cativamente el índice de Barthel, disminuyó el colesterol LDL y aumentó el colesterol HDL frente a placebo + AAS. Conclusiones. El tratamiento a largo plazo (12 meses) con policosanol + AAS fue más efectivo que el tratamiento con placebo + AAS en la recuperación funcional de los pacientes después de sufrir un ictus isquémico no cardioembólico de moderada gravedad (AU)
Introduction. Stroke is a leading cause of mortality and disability. Policosanol has been eff ective in brain ischemia models. The aim of this study is to investigate whether policosanol, added to aspirin therapy within 30 days of stroke onset, is better than placebo + aspirine for the long-term recovery of non-cardioembolic ischemic stroke subjects. Patients and methods. Randomized, double-blind, placebo-controlled study. Eighty patients (mean age: 69 years) within 30 days of onset, with a modifi ed Rankin Scale score (mRS) 2 to 4, were included. They were randomized in two groups (policosanol + aspirine or placebo + aspirine) for 12 months. Results. Policosanol + aspirine decreased signifi cantly mean mRS from the fi rst interim check-up (1.5 months). The treatment even improved after long-term therapy. More policosanol + aspirin (87.5%) than placebo + aspirine (0%) patients achieved mRSs ≤ 1. Policosanol + aspirine increased signifi cantly Barthel Index, lowered LDL-cholesterol and increased HDL-cholesterol versus placebo + aspirin. Conclusions. Long-term (12 months) administration of policosanol + aspirin given after suff ering non-cardioembolic ischemic stroke was shown to be better than placebo + aspirin in improving functional outcomes when used among patients with non-cardioembolic ischemic stroke of moderate severity (AU)
Subject(s)
Humans , Male , Female , Middle Aged , Stroke/drug therapy , Stroke/rehabilitation , Long-Term Care/methods , Aspirin/therapeutic use , Medication Adherence/statistics & numerical data , Repertory, Barthel , Placebos/therapeutic use , Tomography, Emission-Computed/methods , Stroke/prevention & control , Patient Compliance/psychology , Drug Tolerance/physiologyABSTRACT
BACKGROUND: In this study, we evaluated the effects of atorvastatin, a lipid-lowering medication on morphine-induced tolerance and dependence in mice. METHODS: Tolerance was induced by subcutaneous administration of morphine (20mg/kg) to animals, twice a day for 9days. Atorvastatin was given at the doses of 5, 10 and 20mg/kg, 30min before each morphine administration, once daily for 9days. Hot plate test was employed to assess antinociceptive effect of morphine on days 1, 3, 5, 7 and 9. Dependence was evaluated by naloxone-precipitated withdrawal syndrome. We attempted to verify withdrawal regulation of induced nitric oxide synthase (iNOS), astroglia marker, glial fibrillary acidic protein (GFAP), ionized calcium-binding protein (Iba1), a microglia activation marker, a pro-inflammatory mediator, tumor necrosis alpha (TNF-α) and immune receptor, toll like receptor 4 (TLR-4) genes by real-time polymerase chain reaction (RT-PCR). Lipid peroxidation was estimated by assessing malondialdehyde (MDA) content in the spinal cord of animals. RESULTS: Tolerance to antinociceptive effects of morphine was observed on days 7 and 9. Decrease in morphine-induced antinociception was reversed by concomitant intraperitoneal administration of atorvastatin (10 and 20mg/kg). Atorvastatin (10 and 20mg/kg) mitigated naloxone-induced withdrawal parameters. Brain expression levels of TNF-α, GFAP, Iba1 and iNOS increased in morphine withdrawn animals which were attenuated by nine days treatment with atorvastatin. Increased MDA was also normalized in withdrawn animals received atorvastatin. CONCLUSION: Atorvastatin exhibits meaningful protective effects against both tolerance to antinociceptive effects of morphine and withdrawal-induced behavioral profile. Neuroprotective effects of atorvastatin is further supported via inhibition of glia activity and antioxidant effects.
Subject(s)
Antioxidants/pharmacology , Atorvastatin/pharmacology , Drug Tolerance , Morphine Dependence/drug therapy , Morphine/pharmacology , Narcotics/pharmacology , Animals , Astrocytes/drug effects , Astrocytes/metabolism , Brain/drug effects , Brain/metabolism , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Drug Tolerance/physiology , Male , Mice , Microglia/drug effects , Microglia/metabolism , Morphine Dependence/metabolism , Naloxone/pharmacology , Nociception/drug effects , Nociception/physiology , Random Allocation , Substance Withdrawal Syndrome/drug therapy , Substance Withdrawal Syndrome/metabolismABSTRACT
ETHNOPHARMACOLOGICAL RELEVANCE: Repeated administration of morphine for chronic pain leads to dependence and tolerance that limits clinical usage. Nepeta menthoides is commonly known as Iranian Ustukhuddoos and are administered in traditional medicine for gastrodynia, bone pain, blood depurative and restlessness. AIMS OF STUDY: To investigate the effects of Nepeta menthoides on expression and acquisition of morphine dependence and tolerance in mice with regard to oxidative stress. MATERIALS AND METHODS: Morphine dependence in mice was developed by administration of gradually increasing doses of morphine twice daily for 7 consecutive days. In experimental groups, administration of Nepeta menthoides (200 and 400mg/kg), methadone and their combination were performed 60min prior to each morphine injection (for acquisition) or the last injection of morphine on test day (for expression). Morphine tolerance was measured by the tail-immersion test before and after the administration of a single dose of morphine (100mg/kg; i.p.) on the test day (8th day). Morphine dependence was also evaluated by counting the number of jumps after the injection of naloxone (5mg/kg; i.p.). RESULTS: Nepeta menthoides, similar to methadone, significantly prevented the development (but not the expression) of morphine dependence, tolerance, and potentiated morphine antinociception and also reduced (23.23±1.15) Nitric oxide (NO) overproduction (35.23±3.36) (in compared with naloxone group (6.3±0.52)). However, single and repeated application of the extract could not change high single-dose morphine analgesia. CONCLUSION: It appears that Nepeta menthoides and methadone prevented morphine dependence and tolerance, partly through inhibition of the NO overproduction.
Subject(s)
Morphine Dependence/metabolism , Morphine Dependence/prevention & control , Nepeta , Nitric Oxide/antagonists & inhibitors , Nitric Oxide/biosynthesis , Plant Extracts/therapeutic use , Animals , Dose-Response Relationship, Drug , Drug Tolerance/physiology , Male , Methadone/pharmacology , Methadone/therapeutic use , Mice , Oxidative Stress/drug effects , Oxidative Stress/physiology , Plant Extracts/isolation & purification , Plant Extracts/pharmacology , Random AllocationABSTRACT
BACKGROUND: Increasing evidence suggests that microRNAs are functionally involved in the initiation and maintenance of pain hypersensitivity, including chronic morphine analgesic tolerance, through the posttranscriptional regulation of pain-related genes. We have previously demonstrated that miR-219 regulates inflammatory pain in the spinal cord by targeting calcium/calmodulin-dependent protein kinase II gamma (CaMKIIγ). However, whether miR-219 regulates CaMKIIγ expression in the dorsal root ganglia to mediate morphine tolerance remains unclear. RESULTS: MiR-219 expression was downregulated and CaMKIIγ expression was upregulated in mouse dorsal root ganglia following chronic morphine treatment. The changes in miR-219 and CaMKIIγ expression closely correlated with the development of morphine tolerance, which was measured using the reduction of percentage of maximum potential efficiency to thermal stimuli. Morphine tolerance was markedly delayed by upregulating miR-219 expression using miR-219 mimics or downregulating CaMKIIγ expression using CaMKIIγ small interfering RNA. The protein and mRNA expression of brain-derived neurotrophic factor were also induced in dorsal root ganglia by prolonged morphine exposure in a time-dependent manner, which were transcriptionally regulated by miR-219 and CaMKIIγ. Scavenging brain-derived neurotrophic factor via tyrosine receptor kinase B-Fc partially attenuated morphine tolerance. Moreover, functional inhibition of miR-219 via miR-219-sponge in naive mice elicited thermal hyperalgesia and spinal neuronal sensitization, which were both suppressed by CaMKIIγ small interfering RNA or tyrosine receptor kinase B-Fc. CONCLUSIONS: These results demonstrate that miR-219 contributes to the development of chronic tolerance to morphine analgesia in mouse dorsal root ganglia by targeting CaMKIIγ and enhancing CaMKIIγ-dependent brain-derived neurotrophic factor expression.
Subject(s)
Brain-Derived Neurotrophic Factor/metabolism , Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism , Drug Tolerance/physiology , Ganglia, Spinal/drug effects , Gene Expression Regulation/drug effects , MicroRNAs/metabolism , Morphine/pharmacology , Analgesics, Opioid/pharmacology , Animals , CREB-Binding Protein/metabolism , Calcium-Calmodulin-Dependent Protein Kinase Type 2/genetics , Disease Models, Animal , Freund's Adjuvant/toxicity , Ganglia, Spinal/metabolism , Gene Expression Regulation/physiology , Hyperalgesia/drug therapy , Hyperalgesia/etiology , Hyperalgesia/metabolism , Male , Mice , MicroRNAs/genetics , Pain/chemically induced , Pain/drug therapy , Proto-Oncogene Proteins c-fos/metabolism , RNA, Small Interfering/genetics , RNA, Small Interfering/pharmacology , Signal Transduction/drug effects , Time FactorsABSTRACT
BACKGROUND: Evidence suggests that electroacupuncture (EA) protects against arrhythmia and myocardial injury induced by myocardial ischaemia-reperfusion. However, to our knowledge, it remains unknown whether EA could alleviate bupivacaine-induced cardiotoxicity. Therefore, we aimed to explore the effect of EA pretreatment on bupivacaine-induced cardiac arrest and outcomes of cardiopulmonary resuscitation (CPR) in rats. METHODS: 24 adult male Sprague-Dawley rats were randomly divided into two groups: EA (n=12), and minimal acupuncture (MA) (n=12). Rats in both groups were needled at bilateral PC6, ST36, and ST40. Needles in the EA group were electrically stimulated for 60â min. ECG and invasive arterial blood pressure measurements were recorded. Two hours after EA or MA, 10â mg/kg bupivacaine was infused intravenously at a rate of 5â mg/kg/min in all rats. Rats suffering cardiac arrest were immediately subjected to CPR. At the end of the experiment, arterial blood samples were taken from surviving rats for blood gas analysis. RESULTS: The time from bupivacaine infusion until 20% prolongation of the QRS and QT interval, and the time to cardiac arrest, were notably increased among the rats pretreated with EA. Moreover, EA pretreatment significantly improved mean arterial pressure and heart rate at all monitored points after bupivacaine infusion. The proportion of animals surviving was higher in the EA group (9/12) than the MA group (3/12) at the end of experiment (p=0.039). CONCLUSIONS: Tolerance to bupivacaine-induced cardiotoxicity appeared to be increased following EA pre-treatment. The mechanism of action underlying the effects of EA on bupivacaine-induced cardiotoxicity requires further investigation.
Subject(s)
Anesthetics, Local/adverse effects , Arrhythmias, Cardiac/prevention & control , Bupivacaine/adverse effects , Electroacupuncture/methods , Heart Arrest/prevention & control , Animals , Arrhythmias, Cardiac/chemically induced , Arterial Pressure/physiology , Blood Pressure/physiology , Cardiotoxicity/prevention & control , Disease Models, Animal , Drug Tolerance/physiology , Heart Arrest/chemically induced , Heart Rate/physiology , Male , Pre-Exposure Prophylaxis , Rats , Rats, Sprague-Dawley , Time Factors , Treatment OutcomeABSTRACT
The α2δ-1 subunit of the voltage-gated Ca(2+) channel (VGCC) is a molecular target of gabapentin (GBP), which has been used as a first-line drug for the relief of neuropathic pain. GBP exerts its anti-nociceptive effects by disrupting trafficking of the α2δ-1 subunit to the presynaptic membrane, resulting in decreased neurotransmitter release. We previously showed that GBP has an anti-allodynic effect in the first two weeks; but this is followed by insensitivity in the later stage after repeated administration in a rat model of central post-stroke pain (CPSP) hypersensitivity induced by intra-thalamic hemorrhage. To explore the mechanisms underlying GBP insensitivity, the cellular localization and time-course of expression of the α2δ-1 subunit in both the thalamus and spinal dorsal horn were studied in the same model. We found that the α2δ-1 subunit was mostly localized in neurons, but not astrocytes and microglia. The level of α2δ-1 protein increased in the first two weeks after injury but then decreased in the third week, when GBP insensitivity occurred. Furthermore, the α2δ-1 down-regulation was likely caused by later neuronal loss in the injured thalamus through a mechanism other than apoptosis. In summary, the present results suggest that the GBP receptor α2δ-1 is mainly expressed in thalamic neurons in which it is up-regulated in the early stage of CPSP but this is followed by dramatic down-regulation, which is likely associated with GBP insensitivity after long-term use.
Subject(s)
Amines/pharmacology , Analgesics/pharmacology , Calcium Channels/biosynthesis , Cyclohexanecarboxylic Acids/pharmacology , Drug Tolerance/physiology , Hyperalgesia/metabolism , gamma-Aminobutyric Acid/pharmacology , Animals , Blotting, Western , Disease Models, Animal , Down-Regulation , Fluorescent Antibody Technique , Gabapentin , Hyperalgesia/etiology , Male , Neuralgia/etiology , Neuralgia/metabolism , Neurons/metabolism , Rats , Rats, Sprague-Dawley , Stroke/complications , Thalamus/metabolismABSTRACT
Drug-induced liver injury (DILI) is the most common organ toxicity encountered in regulatory animal toxicology studies required prior to the clinical development of new drug candidates. Very few reports have evaluated the value of these studies for predicting DILI in humans. Indeed, compounds inducing liver toxicity in regulatory toxicology studies are not always correlated with a risk of DILI in humans. Conversely, compounds associated with the occurrence of DILI in phase 3 studies or after market release are often tested negative in regulatory toxicology studies. Idiosyncratic DILI is a rare event that is precipitated in an individual by the simultaneous occurrence of several critical factors. These factors may relate to the host (e.g. human leukocyte antigen polymorphism, inflammation), the drug (e.g. reactive metabolites) or the environment (e.g. diet/microbiota). This type of toxicity therefore cannot be detected in conventional animal toxicology studies. Several animal models have recently been proposed for the identification of drugs with the potential to cause idiosyncratic DILI: rats treated with lipopolysaccharide, Sod2(+/-) mice, panels of inbred mouse strains or chimeric mice with humanized livers. These models are not suitable for use in the prospective screening of new drug candidates. Humans therefore constitute the best model for predicting and assessing idiopathic DILI.
Subject(s)
Chemical and Drug Induced Liver Injury/prevention & control , Drug Evaluation, Preclinical/methods , Models, Animal , Animals , Chemical and Drug Induced Liver Injury/etiology , Chemical and Drug Induced Liver Injury/physiopathology , Drug Tolerance/physiology , Humans , Mice , RatsABSTRACT
OBJECTIVES: Recent evidence associates omega-3 fatty acids (O3) with pain reduction. The aim of this work was to evaluate the antinociceptive effect of O3, either alone or in combination with morphine after acute and chronic administration in rats. As well, a new pharmaceutical mixture that allows the concomitant administration of O3 and morphine as an oral solution was developed. METHODS: Animals were fed on a control or an experimental diet supplemented with O3. They were subjected to the hot-plate test to assess analgesic effect and tolerance to the analgesic effect of morphine. The open-field test was carried out to determine if the differences in the response latency can be related to non-specific sedative effects. KEY FINDINGS: O3 dietary supplementation increased the response latency compared with the control group. Acute treatment with morphine in these groups resulted in an additive antinociceptive effect not related to locomotor activity. Chronic coadministration of morphine with O3 attenuated the development of tolerance. Oral administration of the new pharmaceutical mixture showed analgesic activity with a subtherapeutic dose of morphine. CONCLUSION: This finding suggests a role for O3 as adjuncts to opioids in pain therapy and might contribute to the reduction of the occurrence of morphine side-effects.
Subject(s)
Analgesics/pharmacology , Fatty Acids, Omega-3/administration & dosage , Morphine/pharmacology , Analgesia/methods , Animals , Drug Synergism , Drug Therapy, Combination/methods , Drug Tolerance/physiology , Hot Temperature/adverse effects , Male , Pain/drug therapy , Pain Management/methods , Pain Measurement/methods , Rats, WistarABSTRACT
Narcotic analgesics, especially morphine, exert significantly different effects depending on the time within one day. The objective of this study was to observe whether the dosing time of 6 narcotic analgesics in mice affected their efficacy, pain tolerance and recovery of tolerance. The chronopharmacology of these 6 narcotics was evaluated using a hot-plate model. Maximum possible effect (MPE) of morphine showed a significant 24 h rhythm, which was higher during the dark phase and lower during the light phase (P<0.05). Conversely, MPEs of fentanyl and bucinnazine groups during the light phase exceeded those during the dark phase (P<0.05). Pain tolerance developed after drug administration at 9:00 am or 9:00 pm for 5 days, of which bucinnazine produced lower tolerance at 9:00 am. After a 2-day washout period, the mice rapidly recovered from tolerance at 3:00 pm for 5-day morphine dosing at 9:00 pm, and for fentanyl dosing at 9:00 am. Not all narcotic analgesics displayed significant circadian variations, and the dosing time-dependent effects also depended on the types of narcotics. Therefore, the time of administration is crucial in clinical pain treatment. Chronotherapy may be more effective to relieve pain while reducing side effects.
Subject(s)
Analgesics, Opioid/administration & dosage , Drug Tolerance/physiology , Narcotics/administration & dosage , Pain/drug therapy , Animals , Dose-Response Relationship, Drug , Female , Fentanyl/administration & dosage , Mice , Mice, Inbred BALB C , Morphine/administration & dosageABSTRACT
Pregabalin is recently proposed as analgesic or adjuvant in pain management. While previous preclinical investigations have evaluated pregabalin-opioid interactions, the effect of pregabalin on opioid tolerance and dependency has not yet been studied. Here we evaluated the effects of different doses of pregabalin (50, 100 and 200mg/kg, s.c.) on morphine-induced tolerance and dependency in rats. Adult male Wistar rats were rendered tolerant to analgesic effect of morphine by injection of morphine (10mg/kg, s.c.) twice daily for 7 days. To develop morphine dependence, rats were given escalating doses of morphine. To determine the effect of pregabalin on the development of morphine tolerance and dependence, different doses of pregabalin were administrated before morphine. The tail-flick and naloxone precipitation withdrawal tests were used to evaluate the degree of tolerance and dependence, respectively. Chronic morphine-injected rats showed significant decrements in the percentage maximum possible effect (%MPE) of morphine on the days 5 and 7 (32.5%±3.5, 21.5%±4, respectively) compared to the first day (100%) which showed morphine tolerance. Pregabalin 200mg/kg completely prevented the development of morphine tolerance. In addition, concomitant treatment of morphine with pregabalin attenuated almost all of the naloxone-induced withdrawal signs which include weight loss, jumping, penis licking, teeth chattering, wet dog shakes, rearing, standing, sniffing, face grooming and paw tremor. These data show that pregabaline has a potential anti-tolerant/anti-dependence property against chronic usage of morphine. Therefore, pregabalin appears to be a promising candidate for the treatment of opioid addiction after confirming by future clinical studies.
Subject(s)
Analgesics, Opioid/pharmacology , Drug Tolerance/physiology , Morphine Dependence/drug therapy , Morphine/pharmacology , gamma-Aminobutyric Acid/analogs & derivatives , Analgesics, Opioid/administration & dosage , Animals , Disease Models, Animal , Dose-Response Relationship, Drug , Male , Morphine/administration & dosage , Morphine Dependence/physiopathology , Pain Measurement/drug effects , Pregabalin , Rats , Rats, Wistar , Substance Withdrawal Syndrome/drug therapy , Substance Withdrawal Syndrome/physiopathology , gamma-Aminobutyric Acid/pharmacologyABSTRACT
The analgesic effectiveness of long-term opioid therapies is compromised by the development of antinociceptive tolerance linked to the overt production of peroxynitrite (ONOO(-), PN), the product of the interaction between superoxide (O2(-), SO) and nitric oxide (NO), and to neuroinflammatory processes. We have recently reported that in addition to post-translational nitration and inactivation of mitochondrial manganese superoxide dismutase (MnSOD), activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase holoenzyme (NOX) in the spinal cord is a major source for the overt production of superoxide-derived PN during the development of morphine-induced antinociceptive tolerance. However, the NOX complex involved in these processes is not known. The objective of these studies is to identify a potential role for the NOX2 complex, an enzyme involved in inflammation. Mice lacking the catalytic subunit of NOX2 (Nox2(-/-)) or its regulatory subunit, p47(phox) (p47(phox)(-/-)), developed antinociceptive tolerance similar to wildtype (wt) mice after 3 days of continuous morphine. However, while wt mice continue to develop tolerance by day six, morphine analgesia was restored in both Nox2(-/-) and p47(phox)(-/-) mice. Moreover, the loss of Nox2 or p47 did not affect acute morphine analgesia in naïve mice. In wt mice, antinociceptive tolerance was associated with increased activation of NOX, nitration of MnSOD, and proinflammatory cytokines production in the spinal cord. These events were markedly attenuated in Nox2(-/-) and p47(phox)(-/-) mice and instead, there was enhanced formation of antiinflammatory cytokine (IL4 and IL10) production. These results suggest that NOX2 activity provides a significant source of superoxide-derived PN to undertake post-translational modifications of mitochondrial MnSOD and to engage neuroinflammatory signaling in the spinal cord associated with opioid-induced antinociceptive tolerance. Thus, NOX2 may provide a potential target for adjuvant therapy to protect opioid analgesia.