Injection Of Naloxone Research Articles

Motor effects of fentanyl in isoflurane-anaesthetized pigs and the subsequent effect of ketanserin or naloxone

ObjectiveTo examine the effect of ketanserin and naloxone on fentanyl-induced motor activity in isoflurane-anaesthetized pigs. Study designRandomized, blinded, prospective two-group study. AnimalsA group of 12 crossbred pigs weighing 22–31 kg. MethodsFentanyl was administered to isoflurane-anaesthetized pigs at 7.5 μg kg–1 hour–1 for 40 minutes intravenously, followed by an intravenous injection of naloxone 0.1 mg kg–1 or ketanserin 1 mg kg–1. Electromyography (EMG) and accelerometry were used to record motor unit activity and tremors, respectively. To test the effect of drug administration on motor activity, data from a 5 minute period at baseline, immediately before and after antagonist injection were compared in a mixed model; p < 0.05. ResultsResults are reported with the median difference, 95% confidence intervals and corresponding p-values in brackets. Fentanyl significantly increased EMG activity [30.51 (1.84–81.02) μV, p = 0.004] and induced tremors [0.09 (0.02–0.18) m s–2, p < 0.001] in 10 of 12 pigs. Ketanserin significantly reduced EMG [32.22 (6.29–136.80) μV, p = 0.001] and tremor [0.10 (0.03–0.15) m s–2, p = 0.007] activity. No significant effect was found for naloxone on EMG [26.76 (–13.28–91.17) μV, p = 0.4] or tremors [0.08 (–0.01–0.19) m s–2, p = 0.08]. Conclusions and clinical relevanceFentanyl can induce motor activity in anaesthetized pigs, with a suggested link to the serotonergic system. This study shows that ketanserin can antagonize this activity, which supports the role of serotonin. This knowledge contributes to the general understanding of the motor effects of fentanyl and especially the problem of tremors in anaesthetized pigs.

A rat model of operant negative reinforcement in opioid-dependent males and females.

Avoidance of opioid withdrawal plays a key role in human opioid addiction. Here, we present a procedure for studying operant negative reinforcement in rats that was inspired by primate procedures where opioid-dependent subjects lever-press to prevent naloxone infusions. In Experiment 1, we trained rats (n = 30, 15 females) to lever-press to escape and then avoid mild footshocks (0.13-0.27mA) for 35days (30 trials/d). Next, we catheterized them and implanted minipumps containing methadone (10mg/kg/day) or saline. We then paired (4 times, single session) a light cue (20-s) with a naloxone infusion (20µg/kg, i.v) that precipitated opioid withdrawal. Next, we trained the rats to escape naloxone injections for 10days (30 trials/d). Each trial started with the onset of the opioid-withdrawal cue. After 20-s, the lever extended, and an infusion of naloxone (1 to 2.2µg/kg/infusion) began; a lever-press during an 11-s window terminated the withdrawal-paired cue and the infusion. In Experiment 2, we trained rats (n = 34, 17 females) on the same procedure but decreased the footshock escape/avoidance training to 20days. All rats learned to lever-press to escape or avoid mild footshocks. In both experiments, a subset, 56% (10/18) and 33% (8/24) of methadone-dependent rats learned to lever-press to escape naloxone infusions. We introduce an operant negative reinforcement procedure where a subset of opioid-dependent rats learned to lever-press to escape withdrawal-inducing naloxone infusions. The procedure can be used to study mechanisms of individual differences in opioid negative reinforcement-related behaviors in opioid-dependent rats.

Fact vs. fiction: naloxone in the treatment of opioid-induced respiratory depression in the current era of synthetic opioids.

Opioid-induced respiratory depression (OIRD) deaths are ~80,000 a year in the US and are a major public health issue. Approximately 90% of fatal opioid-related deaths are due to synthetic opioids such as fentanyl, most of which is illicitly manufactured and distributed either on its own or as an adulterant to other drugs of abuse such as cocaine or methamphetamine. Other potent opioids such as nitazenes are also increasingly present in the illicit drug supply, and xylazine, a veterinary tranquilizer, is a prevalent additive to opioids and other drugs of abuse. Naloxone is the main treatment used to reverse OIRD and is available as nasal sprays, prefilled naloxone injection devices, and generic naloxone for injection. An overdose needs to be treated as soon as possible to avoid death, and synthetic opioids such as fentanyl are up to 50 times more potent than heroin, so the availability of new, higher-dose, 5-mg prefilled injection or 8-mg intranasal spray naloxone preparations are important additions for emergency treatment of OIRDs, especially by lay people in the community. Higher naloxone doses are expected to reverse a synthetic overdose more rapidly and the current formulations are ideal for use by untrained lay people in the community. There are potential concerns about severe withdrawal symptoms, or pulmonary edema from treatment with high-dose naloxone. However, from the perspective of first responders, the balance of risks would point to administration of naloxone at the dose required to combat the overdose where the risk of death is very high. The presence of xylazines as an adulterant complicates the treatment of OIRDs, as naloxone is probably ineffective, although it will reverse the respiratory depression due to the opioid. For these patients, hospitalization is particularly vital. Education about the benefits of naloxone remains important not only in informing people about how to treat emergency OIRDs but also how to obtain naloxone. A call to emergency services is also essential after administering naloxone because, although the patient may revive, they may overdose again later because of the short half-life of naloxone and the long-lasting potency of fentanyl and its analogs.

In vivo analgesic, anti-inflammatory and molecular docking studies of S-naproxen derivatives

In the current studies two naproxen derivatives (NPD) were evaluated for analgesic and anti-inflammatory properties. The acetic acid and hot plate animal models were used to screen the compounds for analgesic potential. While the anti-inflammatory potential was evaluated through animal paw edema, induced by several inflammatory mediators (carrageenan, bradykinin, and prostaglandin E2), the xylene-induced ear edema was also used as an inflammatory model. Both NPDs showed significant (p < 0.001) antinociceptive effects in the acetic acid-induced writhing paradigm. In the case of the hot plate, the NPD 1 at the tested dose of 5 mg/kg enhanced the latency time after 60 min of injection, which remained significant (p < 0.001) up to the end of the experiment duration. The maximum percent inhibition of NPD 1 was 87.53. The naloxone injection significantly lowered the latency time of NPD 1 as compared to NPD 2. Regarding the anti-inflammatory effect, both of the tested NPDs demonstrated a significant reduction in paw edema against various inflammatory mediators, as mentioned above; however, the anti-inflammatory effect of NPD 1 was better. The maximal percent inhibition by NPD 1 and 2 was 43.24 (after 60 min) and 45.93 (after 90 min). A considerable effect also resulted from xylene-induced ere edema. Further, a molecular docking study was carried out to investigate the binding modes of the NPD. The docking analysis revealed that the NPD significantly interacted with the COX2 enzyme. Furthermore, molecular dynamics simulation was carried out for the docked complexes. The MD simulation analysis revealed the high stability of the two naproxen derivatives.

Naloxone Effects against Cutaneous Leishmaniasis Caused by Leishmania major Strain MRHO/IR/75/ER in the BALB/c Mice.

Cutaneous leishmaniasis (CL) is a serious health problem in some parts of the world, such as Iran. Since the use of pentavalent antimonial compounds such as meglumine antimoniate (Glucantime, MA) for the treatment of CL has side effects, naloxone as a new treatment in the footpad of Leishmania major (L. major)-infected BALB/c mice was investigated by evaluating the lesion size and the parasite burden. The animals were infected with L. major (MRHO/IR/75/ER). 40 BALB/c mice were divided into 4 groups (10/group), and were treated as follows 39 days after L. major infection: Group 1 treated with intraperitoneal injections of MA (100 mg/kg, positive control group) daily for six weeks; Group 2 received a 100 μl injection of PBS (negative control group); Group 3 received subcutaneous (SC) injections of naloxone (10 mg/kg) daily for six weeks (Naloxone1), and Group 4 was SC injected with naloxone (10 mg/kg) weekly for six weeks (Naloxone2). The lesion size was measured using a digital caliper. After the end of treatment, the lesion parasite burden was evaluated. As compared to the negative control group, the groups that received MA and naloxone (groups 1, 3, and 4) showed fewer parasites. CONCLUSION; Also, the naloxone-treated mice showed significantly smaller lesion sizes than the negative control group (p˂0.05), but they did not differ significantly from the MA-treated mice. Taken together, the results suggest that naloxone might be a promising and alternative treatment for CL.

NMDA Receptors in the Rat Paraventricular Thalamic Nucleus Reduce the Naloxone-induced Morphine Withdrawal.

NMDA receptors have a significant role in the development of opioid physical dependence. Evidence demonstrated that a drug of abuse enhances neuronal excitability in the Paraventricular Nucleus (PVT). The current research studied whether blocking NMDA receptors through the administration of MK801 in the PVT nucleus could affect the development of Morphine (Mor) dependence and hence the behavioral indices induced by morphine withdrawal in rats. Male Wistar rats weighing 250-300 g were used. For induction of drug dependence, we injected Mor subcutaneously (s.c.) (6, 16, 26, 36, 46, 56, and 66 mg/kg, 2 ml/kg) at an interval of 24 hours for 7 days. Animals were divided into two groups in which the NMDA receptor antagonist, MK801 (20 mM in 0.1 ml), or its vehicle were applied into the PVT nucleus for 7 days before each Mor administration. On day 8, after injection of naloxone (Nal, 2.5 mg/kg, i.p.), withdrawal behaviors were checked for 25 min. The current results demonstrated that the blockade of the NMDA receptor in the PVT nucleus significantly increased withdrawal behaviors provoked by the application of Nal in morphinedependent (Mor-d) rats. We concluded that the NMDA receptor in the PVT nucleus changes the development of Mor dependence.

In-vitro and in-vivo assessment of the anti-diabetic, analgesic, and anti-inflammatory potenstials of metal-based carboxylates derivative

In the current research work, an amide based metal carboxylate chemical ([((5-((5-(2-hydroxyethyl)-4-methylthiazol-3-ium-3-yl)methyl)-2-methylpyrimidin-4-yl)amino)bis((4-((4-methoxy-2-nitrophenyl)amino)-4-oxobutanoyl)oxy)zinc]) was identified as anti-diabetic analgesic and anti-inflammatory. The identified chemical(MT-1) was tested for acute toxicity (the MT-1 was fund safe), antidiabetic analgesic, and anti-inflammatory potentials. The in-vitro study was conducted for antidiabetic enzyme inhibition (α-amylase and α-glucosidase) and the in-vivo studies included analgesic (acetic acid-induced writing and hot plate model) and anti-inflammatory (carrageenan etc induced edema) effects. The tested compound showed 88.63% (IC50 = 3.23 μg/ml) and 89.10%(IC50 = 5.10 μg/ml) againstα-amylase and α-glucosidase respectively. A significant (p < 0.001) analgesic effect was noted by MT-1 in acetic acid-induced animal models with a percent effect of 86.00, 60.,06, and 55.29 at the tested doses of 20, 1,0, and 5 mg/kg respectively. In the case of the hot plate model, the MT-1 showed a significant (p < 0.001) effect with maximum percent prolongation in latency observed after 60 min.08, 22.2,9, and 11.61) against 20, 1,0, and 5 mg/kg. The analgesic effect in the hot plate model was significantly (p < 0.01) reversed by the injection of naloxone (0.125 mg/kg). The paw edema induced by carrageenan, histamine, bradykinin, arachidonic acid, and PGE2 was significantly antagonized with percent attenuation of 34.09, 33.57, 34.60, 34.14, and 48.04 respectively. Furthermore, to predict the interactions between the MT-1 compound and COX-2 molecular docking was carried out and the result was compared with the standard compound. The docking score of MT-1 was predicted as −6.30 while that of Diclofenac was predicted as −6.82. Both compounds made several hydrogen bond interactions with the active site of the COX-2 enzyme. The docking study revealed the potent inhibitory potential of the compound MT-1 against the COX-2 receptor.

Opioid Overdose Detection in a Murine Model Using a Custom-Designed Photoplethysmography Device

Background and ObjectiveOver 68,000 opioid-overdose related deaths occurred within the United States in 2020 alone, indicating a need to develop technologies to help curb this growing epidemic. The ability to detect respiratory rate (RR) depression in real-time has the potential to decrease adverse outcomes by alerting emergency medical services or willing bystanders to an overdose event. The aim of this investigation was to design, build, and test a novel photoplethysmography (PPG)-based measurement device capable of monitoring RR and identifying respiratory depression. Materials and MethodsWe developed a novel murine model for opioid-induced respiratory depression (OIRD) to demonstrate the PPG device's capabilities. We induced respiratory depression in mice using both isoflurane and opioid-overdose and initiated recovery events with injections of naloxone while monitoring respiration via PPG and a laboratory reference system. Results and DiscussionThe device accurately identified all anesthesia-induced respiratory depression (n = 5) and OIRD events (n = 3). Our PPG-based monitor showed significant correlation with a reference respiratory measurement system (p<0.01). The bias measured across the isoflurane trials was 0.6 breaths per minute (BrPM), while the bias measured across the oxycodone trials was −1.0 BrPM, with mean absolute errors of 1.5 and 3.6 BrPM, respectively, indicating that our device was able to accurately measure RR in a murine model. ConclusionsThese preliminary experiments suggest that our device could detect OIRD and could potentially be adaptable to humans with modifications to firmware and more extensive validation in human subjects. Our present study is a proof-of-concept for detecting OIRD and alerting bystanders and health professionals in real-time.

Distinctive roles of L-type calcium channels subtypes within the dorsal hippocampus in formation of morphine withdrawal-induced aversion in rats

Although the negative effects coming along with opiate withdrawal are in part modulated by L-type calcium channels (LTCCs), the distinctive physiological properties and functions of LTCCs subtypes suggest differential roles of subtypes during withdrawal. The present study aimed to examine the contributions of LTCC subtypes, Cav1.2 and Cav1.3, within the dorsal hippocampus (DH) in naloxone-precipitated morphine withdrawal using the conditioned place aversion (CPA) paradigm. Firstly, we injected the non-specific LTCCs antagonist verapamil into the DH of morphine-dependent rats before conditioning an environment with naloxone-precipitated withdrawal. Our results showed that verapamil blocked the acquisition of CPA. Then, to explore the molecular mechanisms of LTCCs subtypes during withdrawal, we measured the protein expression of Cav1.2 and Cav1.3 in morphine-dependent rats under different conditions. In morphine-dependent rats, conditioning with withdrawal increased Cav1.2 expression in the membrane, while only acute naloxone injection increased the membrane expression of Cav1.3. To further determine the causal roles of LTCCs subtypes in the withdrawal process, we used Cav1.2 siRNA or Cav1.3 shRNA to knock down the expression of subtypes and detected the effects on CPA and somatic withdrawal signs in morphine-dependent rats. Cav1.2 siRNA, but not Cav1.3 shRNA, inhibited the acquirement of CPA and relieved somatic withdrawal symptoms. Together, our findings reveal that Cav1.2, but not Cav1.3 plays an important role in mediating morphine withdrawal, suggesting this subtype may serve as a potential therapeutic target for the treatment of negative effects in opiate dependence.

A history of ethanol intake accelerates the development of morphine analgesic tolerance: A protective potential for omega-3 fatty acids.

Adolescence is a critical life period during which significant neurodevelopmental changes occur within the central nervous system. Consistently, substance abuse in this stage has been found to induce persistent changes in brain responsiveness to future drug challenges. Nowadays, heavy episodic alcohol consumption during adolescence, also known as binge-drinking behavior, is a growing concern in modern societies. On the other hand, alcohol is well known to act as a gateway drug, that is, it promotes the individual's craving for consumption of other drugs of abuse. With this in mind, we aimed to assess whether adolescent ethanol exposure could alter the development of tolerance and dependence to morphine, as an available common opioid drug. Tail flick test was used to measure thermal nociceptive changes in adult male Wistar rats undergone ethanol/vehicle exposure during adolescence. Furthermore, morphine withdrawal syndrome was induced by naloxone injection, and behavioral signs were recorded for 20 min. It was found that adolescent ethanol intake facilitates morphine analgesic tolerance and decreases baseline latency; however, the severity of dependence is not significantly altered. Moreover, we found that 15 days of treatment with omega-3 fatty acids (O3) prevents the mentioned ethanol-induced changes suggesting a therapeutic potential for this compound. O3 supplementation, as an inexpensive and noninvasive method, may assist the clinicians to reverse the adverse effect of alcohol binge drinking on adolescents' brains and to reduce the vulnerability to drug exposure in adulthood. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Histamine and its H1 receptors in the ventral pallidum mediate formalin-induced pain-related behaviors through this region and spinal cord opioid receptors.

Many structures of the central nervous system recruit different neurotransmitters in pain processing. This study focused on the contribution of histamine and its H1 receptors in the ventral pallidum (VP) in mediating pain-triggered behaviors. Intra-VP microinjection of histamine and 2-pyridylethylamine (2-PEA, a histamine H1 receptor agonist) at the same doses of 0.5 and 1 µg/200 nl reduced both the first and second phases of licking/biting duration as well as flinching number induced by intra-plantar (ipl) injection of formalin (2.5%, 50 µl). Premicroinjection of mepyramine (a histamine H1 antagonist, 2 µg/200 nl) into the VP antagonized the suppressive effects of 1 µg/200 nl histamine and 2-PEA on licking/biting and flinching behaviors. The possible mechanisms of the above-mentioned pain-reducing effects were followed by intra-VP and intrathecal administration of naloxone (an opioid receptor antagonist). Naloxone (2 µg/200 nl) preadministration into the VP inhibited attenuating effects of histamine and 2-PEA on both the licking/biting and flinching behaviors, whereas intrathecal injection of naloxone only inhibited their suppressing effects on flinching behavior. None of the treatments used in this study altered the animal's motor activity. The obtained results may reveal the role of histamine and its activated H1 receptor in the VP in suppressing the pain behaviors caused by formalin. Opioid receptors in the VP and spinal cord may contribute to these functions.

The Effect of Troxerutin Consumption on the Symptoms of Morphine Withdrawal Syndrome in Male Mice

Introduction: Chronic morphine use is associated with increased oxidative stress and inflammatory factors. Troxerutin is a natural bioflavonoid and has antioxidant and anti-inflammatory effects that could relieve morphine withdrawal syndrome.&#x0D; Aim: The effects of troxerutin on morphine dependence in mice&#x0D; Method: Troxerutin was prepared in three different doses (50, 100, and 200 mg/kg) via a normal saline solution. After examining the composition of troxerutin, the experiment was performed in five groups of 8 mice. One group received eight days of increasing doses (10, 20, 30, 40, 50, and 60 mg/kg) of morphine SC (subcutaneously) with normal saline (10 ml/kg) IP (Intraperitoneal), and one group received only normal saline and the other three groups received three different doses of troxerutin solved in normal saline as the carrier of troxerutin along with morphine. On the ninth day, withdrawal symptoms were recorded after naloxone injection and blood samples were examined for antioxidant factors.&#x0D; Results: The total withdrawal score in the 50 mg/kg dose of the troxerutin group with morphine was significantly lower than the morphine-saline group (p

Nicorandil reduces morphine withdrawal symptoms, potentiates morphine antinociception, and ameliorates liver fibrosis in rats

AimsChronic liver disease (CLD) is a serious medical condition affecting patients globally and pain management poses a unique challenge. ATP-sensitive potassium channels (KATP) are expressed in nociceptive neurons and hepatic cells. We tested the hypothesis whether morphine and nicorandil, KATP channel opener, alone and in combination possess hepatoprotective, antinociceptive effect and alter morphine physical dependence. Main methodsIntraperitoneal injection (i.p.) of carbon tetrachloride (CCl4) induced liver fibrosis in male Wistar rats. Nicorandil (15 mg/kg/day) was administered per os for two weeks. Morphine (3.8, 5, 10 mg/kg, i.p.) was administered prior to antinociception testing in tail flick and formalin tests. Morphine physical dependence following naloxone injection, fibrotic, oxidative stress markers, and liver histopathology were assessed. Key findingsMorphine alone, produced insignificant changes of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), hepatic hydroxyproline (Hyp), malondialdehyde (MDA), and superoxide dismutase (SOD) levels and exerted significant antinociception in the pain models. Nicorandil alone protected against liver damage (decreased serum ALT, AST, HA, hepatic Hyp, MDA, increased SOD levels, improved fibrosis scores). Nicorandil/morphine combination produced remarkable hepatoprotection and persistent analgesia compared to morphine alone as evidenced by reduced (EC50) of morphine. Nicorandil augmented morphine analgesia and markedly decreased withdrawal signs in morphine-dependent rats. SignificanceThe data showed for the first time, the hepatoprotection and augmented antinociception mediated by nicorandil/morphine combination in liver fibrosis via antioxidant and antifibrotic mechanisms. Nicorandil ameliorated withdrawal signs in morphine dependence in CLD. Thus, combining nicorandil/morphine provides a novel treatment strategy to ameliorate hepatic injury, potentiate antinociception and overcome morphine-induced physical dependence in liver fibrosis.

Behavioral Reaction and c-fos Expression after Opioids Injection into the Pedunculopontine Tegmental Nucleus and Electrical Stimulation of the Ventral Tegmental Area

The pedunculopontine tegmental nucleus (PPN) regulates the activity of dopaminergic cells in the ventral tegmental area (VTA). In this study, the role of opioid receptors (OR) in the PPN on motivated behaviors was investigated by using a model of feeding induced by electrical VTA-stimulation (Es-VTA) in rats (male Wistar; n = 91). We found that the OR excitation by morphine and their blocking by naloxone within the PPN caused a change in the analyzed motivational behavior and neuronal activation. The opioid injections into the PPN resulted in a marked, dose-dependent increase/decrease in latency to feeding response (FR), which corresponded with increased neuronal activity (c-Fos protein), in most of the analyzed brain structures. Morphine dosed at 1.25/1.5 µg into the PPN significantly reduced behavior induced by Es-VTA, whereas morphine dosed at 0.25/0.5 µg into the PPN did not affect this behavior. The opposite effect was observed after the naloxone injection into the PPN, where its lowest doses of 2.5/5.0 μg shortened the FR latency. However, its highest dose of 25.0 μg into the PPN nucleus did not cause FR latency changes. In conclusion, the level of OR arousal in the PPN can modulate the activity of the reward system.

The long-term effects of repeated heroin vapor inhalation during adolescence on measures of nociception and anxiety-like behavior in adult Wistar rats

RationaleAdolescents represent a vulnerable group due to increased experimentation with illicit substances that is often associated with the adolescent period, and because adolescent drug use can result in long-term effects that differ from those caused by drug use initiated during adulthood.ObjectivesThe purpose of the present study was to determine the effects of repeated heroin vapor inhalation during adolescence on measures of nociception, and anxiety-like behavior during adulthood in female and male Wistar rats.MethodsRats were exposed twice daily to 30 min of heroin vapor from post-natal day (PND) 36 to PND 45. At 12 weeks of age, baseline thermal nociception was assessed across a range of temperatures with a warm-water tail-withdrawal assay. Anxiety-like behavior was assessed in an elevated plus-maze (EPM) and activity was measured in an open-field arena. Starting at 23 weeks of age, baseline thermal nociception was re-assessed, nociception was determined after acute heroin or naloxone injection, and anxiety-like behavior was redetermined in the EPM.ResultsAdolescent heroin inhalation altered baseline thermal nociception in female rats at 12 weeks of age and in both female and male rats at ~ 23 weeks. Heroin-treated animals exhibited anxiety-like behavior when tested in the elevated plus-maze, showed blunted heroin-induced analgesia, but exhibited no effect on naloxone-induced hyperalgesia.ConclusionsThe present study demonstrates that heroin vapor inhalation during adolescence produces behavioral and physiological consequences in rats that persist well into adulthood.

Male and female rats show opiate withdrawal-induced place aversion and extinction in a Y-maze paradigm

Gender differences have been observed in the vulnerability to drug abuse and in the different stages of the addictive process. In opiate dependence, differences between sexes have been shown in humans and laboratory animals in various phases of opiate addiction, especially in withdrawal-associated negative affective states. Using a Y-maze conditioned place aversion paradigm, we investigated potential sex differences in the expression and extinction of the aversive memory of precipitated opiate withdrawal state in morphine-dependent rats. No significant difference between sexes was observed in the occurrence of withdrawal signs following naloxone injection during conditioning. Moreover, opiate withdrawal memory expression and extinction following repeated testing was demonstrated in both male and female rats, with no significant differences between sexes. Finally, we report spontaneous recovery following extinction of opiate withdrawal memory. Altogether these data provide further evidence that persistent withdrawal-related memories may be strong drivers of opiate dependence, and demonstrate that both males and females can be used in experimental rodent cohorts to better understand opiate-related effects, reward, aversive state of withdrawal, abstinence and relapse.

Biological and Molecular Docking Evaluation of a Benzylisothiocyanate Semisynthetic Derivative From Moringa oleifera in a Pre-clinical Study of Temporomandibular Joint Pain.

ObjectiveMoringa oleifera possesses multiple biological effects and the 4-[(4′-O-acetyl-α-L- rhamnosyloxy) benzyl] isothiocyanate accounts for them. Based on the original isothiocyanate molecule we obtained a semisynthetic derivative, named 4-[(2′,3′,4′-O-triacetyl-α-L-rhamnosyloxy) N-benzyl] hydrazine carbothioamide (MC-H) which was safe and effective in a temporomandibular joint (TMJ) inflammatory hypernociception in rats. Therefore, considering that there is still a gap in the knowledge concerning the mechanisms of action through which the MC-H effects are mediated, this study aimed to investigate the involvement of the adhesion molecules (ICAM-1, CD55), the pathways heme oxygenase-1 (HO-1) and NO/cGMP/PKG/K+ATP, and the central opioid receptors in the efficacy of the MC-H in a pre-clinical study of TMJ pain.MethodsMolecular docking studies were performed to test the binding performance of MC-H against the ten targets of interest (ICAM-1, CD55, HO-1, iNOS, soluble cGMP, cGMP-dependent protein kinase (PKG), K+ATP channel, mu (μ), kappa (κ), and delta (δ) opioid receptors). In in vivo studies, male Wistar rats were treated with MC-H 1 μg/kg before TMJ formalin injection and nociception was evaluated. Periarticular tissues were removed to assess ICAM-1 and CD55 protein levels by Western blotting. To investigate the role of HO-1 and NO/cGMP/PKG/K+ATP pathways, the inhibitors ZnPP-IX, aminoguanidine, ODQ, KT5823, or glibenclamide were used. To study the involvement of opioid receptors, rats were pre-treated (15 min) with an intrathecal injection of non-selective inhibitor naloxone or with CTOP, naltrindole, or norbinaltorphimine.ResultsAll interactions presented acceptable binding energy values (below −6.0 kcal/mol) which suggest MC-H might strongly bind to its molecular targets. MC-H reduced the protein levels of ICAM-1 and CD55 in periarticular tissues. ZnPP-IX, naloxone, CTOP, and naltrindole reversed the antinociceptive effect of MC-H.ConclusionMC-H demonstrated antinociceptive and anti-inflammatory effects peripherally by the activation of the HO-1 pathway, as well as through inhibition of the protein levels of adhesion molecules, and centrally by μ and δ opioid receptors.

Risk of developing drug abuse in administration of a new hexaazaisowurtzitane derivative-based analgesic (experimental study)

The aim of the study was to assess the probability of developing withdrawal syndrome caused by discontinuation of 5-day administration of thiowurtzine with naloxone challenge test in the experiment.Materials and methods. The test sample of the analgesic “Thiowurtzine, capsule 120 mg” served as the study object. The active pharmaceutical ingredient is an organic, low molecular weight compound 4-(3,4-dibromothiophene carbonyl)-2,6,8,12-tetraacetyl-2,4,6,8,10,12-hexaazatetracyclo [5,5,0,03,11,05,9]dodecane that was first synthesized according to computer modeling results at the IPCET SB RAS (Biysk).The likelihood of developing physical dependence was explored by per os administration of thiowurtzine and the reference drug tramadol twice a day for 5 days as follows: 1) at 9 a.m. – thiowurtzine 50 mg / kg and tramadol 10 mg / kg, at 3 p.m. – thiowurtzine 50 mg / kg and tramadol 10 mg / kg; 2) at 9 a.m. – thiowurtzine 50 mg / kg and tramadol 10 mg / kg, at 3 p.m. – thiowurtzine 75 mg / kg and tramadol 15 mg / kg; 3) at 9 a.m. – thiowurtzine 75 mg / kg and tramadol 15 mg / kg, at 3 p.m. – thiowurtzine 75 mg / kg and tramadol 15 mg / kg; 4) at 9 a.m. – thiowurtzine 100 mg / kg and tramadol 20 mg / kg, at 3 p.m. – thiowurtzine 100 mg / kg and tramadol 20 mg / kg; 5) at 9 a.m. – thiowurtzine 100 mg / kg and tramadol 20 mg / kg, at 3 p.m. – naloxone 10 mg / kg subcutaneously.In all the groups, the intensity of the withdrawal syndrome was studied by specific features in outbred male CD1 mice. During one hour following the naloxone injection, health of mice was assessed according to dominant abstinence components and recessive traits of mild withdrawal syndrome. Two hours after the naloxone injection, the number of mice with negative body weight gain was determined. 24 hours after discontinuation of test compound administration, the open-field test was used to determine the impact on animal behavioral patterns (horizontal and vertical motor and exploratory activity, emotionality and its vegetative manifestations). The hot plate test was carried out to measure the analgesic activity (55˚). The criterion of the withdrawal syndrome severity was a decrease in the number of jumping reactions, changes in the general condition of the animals, stimulation of motor activity, manifestations of hyperalgesia, and a decrease in body weight.Results. No dominant abstinence components and recessive signs of withdrawal syndrome were detected in animals from the thiowurtzine groups. The data obtained in the study (orientation and exploratory behavior, motor activity, emotionality and its vegetative manifestations, grooming, etc.) allow to conclude that thiowurtzine causes no physical dependence in animals after discontinuation of its 5-day administration with naloxone challenge test, as opposed to the reference drug naloxone. A positive disinhibition effect of this analgesic was revealed due to the activated orientation and exploratory behavior (stress caused by the new environment) in the conditions of the open-field test. The animals showed no manifestations of hyperalgesia in the hot plate test. The animals treated with thiowurtzine did not demonstrate any changes in the body weight.Conclusion. The obtained results prove that thiowurtzine is a non-narcotic analgesic. It evokes no side effects typical of opioid analgesics (tramadol), including development of physical dependence and withdrawal syndrome following naloxone challenge test. Previous in vivo and in silico studies (docking, molecular modeling, molecular dynamics simulation) on the multi-target mechanism of thiowurtzine explain the absence of its morphine-like effect by the fact that the major targets of the analgesic are TRPA1 receptors and voltage-gated Ca 2+ channels. With a high degree of probability, the conclusions made herein predict no drug abuse development when thiowurtzine is used in the clinical setting. Absence of ulcerotoxicity found earlier will enable to administer thiowurtzine in long-term cycles for chronic pain syndrome.

Administration of Orexin-A into the Rat Thalamic Paraventricular Nucleus Enhances the Naloxone Induced Morphine Withdrawal.

Orexin neuropeptides are implicated in physical dependence on opioids and expression of withdrawal symptoms in drug abuse. The paraventricular nucleus of the midline thalamus (PVT) has a high expression of orexin receptors. The current research studied the effect of orexin-A in the PVT area on the development of behavioral indices produced by morphine withdrawal in rats. Male Wistar rats weighing 250-300 gr were utilised. To produce drug dependence, morphine (6, 16, 26, 36, 46, 56, and 66 mg/kg, 2 ml/kg) was injected at an interval of 24 hrs for 7 days. To assess the involvement of the orexin in withdrawal syndrome, we injected orexin-A (100 μM, 200 nl) into the PVT for 7 days before each morphine injection. On the day after the last injection of morphine, naloxone (2.5 mg/kg, i.p.) was injected to elicit the morphine withdrawal symptoms which were observed and checked for 25 min. The results of the current research showed that the orexin-A in PVT enhances the severity of behavioral symptoms prompted by the injection of naloxone in drug-dependent rats. These observations imply that targeting the orexin receptors in PVT might exhibit a new therapeutic strategy for the future treatment of dependence.

Acute morphine administration, morphine dependence, and naloxone-induced withdrawal syndrome affect the resting-state functional connectivity and Local Field Potentials of the rat prefrontal cortex

Opiates are among the widely abused substances worldwide. Also, the clinical use of opioids can cause unwanted and potentially severe consequences such as developing tolerance and dependence. This study simultaneously measured the changes induced after morphine dependence and naloxone-induced withdrawal syndrome on the resting-state functional connectivity (rsFC) and Local Field Potential (LFP) power in the prefrontal cortex of the rat. The obtained results revealed that acute morphine administration significantly increased the LFP power in all frequency bands, as well as the rsFC strength of the prefrontal cortex, and naloxone injection reversed this effect. In contrast, chronic morphine administration reduced neural activity and general correlation values in intrinsic signals, as well as the LFP power in all frequency bands. In morphine-dependent rats, after each morphine administration, the LFP power in all frequency bands and the rsFC strength of the prefrontal cortex were increased, and these effects were further enhanced after naloxone precipitated withdrawal syndrome. The present study concludes that general correlation merely reflects the field activity of the local cortices imaged.