Effects Of Morphine Research Articles

Bidirectional effects of morphine on pancreatic cancer progression via the p38/JNK pathway

Cancer patients commonly use morphine to alleviate advanced pain. Studies have shown that morphine may influence and intervene in the malignancy of various cancers, but its role and effects on pancreatic cancer are less studied. This study aims to examine how morphine affects pancreatic cancer and its possible mechanisms. In vitro experiments were conducted using the CCK-8 experiment, colony formation experiment, EdU test, wound healing experiment, and transwell migration and invasion experiment. Tumor xenograft tests were employed to investigate the in vivo impact of morphine on pancreatic cancer. The Western blot (WB) assay was used to detect possible changes in key proteins of the related signaling pathway. Our experimental results showed that low concentrations of morphine (25 µM) promoted the progression of pancreatic cancer, while high concentrations of morphine (100 µM) inhibited its progression. Further, we demonstrated that morphine may interfere with the progression of pancreatic cancer by acting on the p38/JNK signaling pathway. Morphine may affect pancreatic cancer progression through the p38/JNK pathway in a bidirectional manner at different concentrations.

Development of Macrocyclic Neurotensin Receptor Type 2 (NTS2) Opioid‐Free Analgesics

AbstractThe opioid crisis has highlighted the urgent need to develop non‐opioid alternatives for managing pain, with an effective, safe, and non‐addictive pharmacotherapeutic profile. Using an extensive structure–activity relationship approach, here we have identified a new series of highly selective neurotensin receptor type 2 (NTS2) macrocyclic compounds that exert potent, opioid‐independent analgesia in various experimental pain models. To our knowledge, the constrained macrocycle in which the Ile12 residue of NT(7–12) was substituted by cyclopentylalanine, Pro7 and Pro10 were replaced by allyl‐glycine followed by side‐chain to side‐chain cyclization is the most selective analog targeting NTS2 identified to date (Ki 2.9 nM), showing 30,000‐fold selectivity over NTS1. Of particular importance, this macrocyclic analog is also able to potentiate the analgesic effects of morphine in a dose‐ and time‐dependent manner. Exerting complementary analgesic actions via distinct mechanisms of nociceptive transmission, NTS2‐selective macrocycles can therefore be exploited as opioid‐free analgesics or as opioid‐sparing therapeutics, offering superior pain relief with reduced adverse effects to pain patients.

Development of Macrocyclic Neurotensin Receptor Type 2 (NTS2) Opioid-Free Analgesics.

The opioid crisis has highlighted the urgent need to develop non-opioid alternatives for managing pain, with an effective, safe, and non-addictive pharmacotherapeutic profile. Using an extensive structure-activity relationship approach, here we have identified a new series of highly selective neurotensin receptor type 2 (NTS2) macrocyclic compounds that exert potent, opioid-independent analgesia in various experimental pain models. To our knowledge, the constrained macrocycle in which the Ile12 residue of NT(7-12) was substituted by cyclopentylalanine, Pro7 and Pro10 were replaced by allyl-glycine followed by side-chain to side-chain cyclization is the most selective analog targeting NTS2 identified to date (Ki 2.9 nM), showing 30,000-fold selectivity over NTS1. Of particular importance, this macrocyclic analog is also able to potentiate the analgesic effects of morphine in a dose- and time-dependent manner. Exerting complementary analgesic actions via distinct mechanisms of nociceptive transmission, NTS2-selective macrocycles can therefore be exploited as opioid-free analgesics or as opioid-sparing therapeutics, offering superior pain relief with reduced adverse effects to pain patients.

Redesigning a Stopped Clinical Trial as an Emulated Trial Using Real-World Data to Explore the Effectiveness of Slow-Release Oral Morphine as a Treatment for Opioid Use Disorder.

Canada is currently experiencing a problematic opioid crisis with increasing mortality rates. Traditional randomized controlled trials (RCTs) that examine the effectiveness of pharmacological treatment options for people with opioid use disorder (OUD) are challenging to conduct. An increasingly popular methodology is through the implementation of emulated clinical trials, a methodology in which key elements of a "target" RCT are replicated using previously collected healthcare-based data. They can possibly address some of the common challenges found in the conduct of RCTs, such as prolonged timelines, high cost, and poor participant recruitment. In effect, emulated trials accelerate knowledge generation by producing real-world evidence that can be akin to phase 3 effectiveness trials, without any need to recruit live participants or administer investigational products. During the COVID-19 pandemic, several trials were stopped due to increased pandemic-related research restrictions, leaving important questions about OUD treatment unanswered. In this commentary, we describe the transition of a traditional RCT to an emulated trial spurred by challenges posed by the COVID-19 pandemic. We describe our transition using a notable published framework with regards to the population sample, interventions, outcomes, and proposed analyses. This commentary aims to help other researchers and trialists apply emulated trials in substance use research and beyond, emphasizing the role of this methodology in clinical research and advancing scientific knowledge that could be otherwise lost or unattainable.

Comparison of Awake Respiratory Control Versus Sleep Obstructive Sleep Apnea Endotypes.

Most approaches to advance simplified physiology-based precision medicine strategies for obstructive sleep apnea (OSA) focus on sleep parameters (i.e., OSA endotypes). However, wakefulness physiology measures can also provide prediction insight for certain OSA therapies yet their relationship with sleep parameters has not been extensively investigated. This study aimed to investigate potential relationships between awake ventilatory control parameters and sleep OSA endotypes and their potential to predict changes in OSA severity with morphine. Data were acquired from a randomised, cross-over trial that investigated effects of morphine versus placebo on OSA severity and underlying mechanisms. Here, awake ventilatory chemoreflex testing prior to overnight polysomnography was compared with direct measures of sleep respiratory control (e.g., hypercapnic ventilatory responses and loop gain) and OSA endotypes during a separate overnight physiology study (pharyngeal critical closure pressure-Pcrit, muscle responsiveness via genioglossus intramuscular electromyography and arousal threshold via epiglottic pressure catheter to transient continuous positive airway pressure reductions). Twenty-one men with OSA completed both study arms. During placebo, 1) awake chemosensitivity correlated with Pcrit (r=0.726, p=0.001), 2) arousal threshold correlated with awake CO2 ventilatory response threshold (r=-0.467, p=0.047) and basal ventilation (r=-0.500, p=0.029). Awake chemosensitivity and Pcrit also correlated with the apnea-hypopnea index (p<0.001) during placebo. Awake chemosensitivity was predictive of changes in OSA severity with morphine(r=-0.535, p=0.013). In conclusion, awake measures of respiratory control are related to physiological endotypes such as airway collapsibility and arousal threshold during sleep and OSA severity. Awake ventilatory chemosensitivity has the best potential to predict changes in OSA severity with morphine.

Analgesic activity of a new cannabinoid CB1 receptor modulator

Aim. To study the analgesic activity, the effect on motor functions, and the potential ulcerogenic effect of a new 2H-chromene derivative, a cannabinoid CB1 receptor modulator (code name – CHR).Materials and methods. The analgesic activity of the CHR compound was studied when injected intragastrically at an effective dose of 5 mg / kg in mouse models of acute chemogenic pain (formalin test), acute visceral pain (the acetic acid-induced writhing test), and thermal nociception (hot plate test and tail-flick test). It was compared to the effect of tramadol and morphine or diclofenac sodium at doses of 20, 4 or 10 mg / kg, respectively. The effect of a single intragastric injection of the CHR compound at a dose of 5 mg / kg on motor activity was evaluated in the open field test. The potential ulcerogenic effect of the CHR compound at a dose of 5 mg / kg with repeated intragastric administration was compared with the effect of diclofenac sodium at a dose of 10 mg / kg.Results. With subplantar administration of formalin to mice, the 2H-chromene derivative reduced the number of pain reactions by 43–63% (p &lt; 0.05). With intraperitoneal administration of acetic acid to mice, it reduced the number of writhing responses by 50% and had the same analgesic effect as diclofenac sodium and tramadol. In the hot plate test, the CHR compound increased the latency time to painful stimuli by 34% (p &lt; 0.05). In the tailflick test, it increased the latency time to painful thermal sensations by 32% (p &lt; 0.05). The CHR compound at an effective dose of 5 mg / kg did not change the motor activity of mice in the open field test and did not cause the formation of erosions and ulcers in the gastric mucosa when administered repeatedly to rats.Conclusion. The 2H-chromene derivative CHR at an effective dose of 5 mg / kg has a pronounced analgesic effect in mouse models of chemogenic, visceral, and thermal pain, which is as strong as that of tramadol, morphine, and diclofenac sodium used at effective doses. The CHR compound at an effective dose does not inhibit motor functions and does not have an ulcerogenic effect.

New insights in the mechanisms of opioid analgesia and tolerance: ultramicronized palmitoylethanolamide down-modulates vascular endothelial growth factor-A in the nervous system

Growing evidence suggest that opioid analgesics modulate angiogenesis during pathophysiological processes. Vascular endothelial growth factor-A (VEGF-A) was recently proposed to be involved in pain development. To date, no anti-angiogenic drug is used for pain management. When administered in a bioavailable formulation, (i.e., ultramicronized) N-palmitoylethanolamine (PEA) delays the onset of morphine tolerance, improves morphine analgesic activity and reduces angiogenesis in in vivo models. This study aimed at investigating whether VEGF-A is involved in PEA-induced delay of morphine tolerance. The anti-VEGF-A monoclonal antibody bevacizumab was used as a reference drug. Preemptive and concomitant treatment with ultramicronized PEA delayed morphine tolerance and potentiated the analgesic effect of morphine, while counteracting morphine-induced increase of VEGF-A in the nervous system. Similar results were obtained when bevacizumab was administered together with morphine. Of note, bevacizumab showed an analgesic effect per se. In equianalgesic treatment regimens (obtained through increasing morphine doses and associating PEA), PEA resulted in lower expression of VEGF-A in dorsal root ganglia (DRG) and spinal cord compared to morphine alone. Similar results were observed for plasma levels of the soluble VEGF receptor 1 (sFLT-1). Moreover, in morphine treated animals, two pain related genes (i.e., Serpina3n and Eaat2) showed a more than 3-fold increase in their expression at spinal cord and DRG level, with the increase being significantly counteracted by PEA treatment. This study supports the hypothesis that the effects of PEA on morphine analgesia and tolerance may be mediated by the down-modulation of VEGF-A and sFLT-1 in the nervous system and plasma, respectively.

Pharmacokinetics and thermal anti-nociceptive effects of oral morphine in horses.

Morphine is an effective analgesic in horses, however, IV administration at therapeutic doses has been shown to produce dose-dependent neuroexcitation and unwanted gastrointestinal effects. The analgesic effects of morphine have, at least in part, been attributed to the morphine-6-glucuronide (M6G) metabolite. Oral administration to horses results in comparable M6G concentrations to that achieved following IV administration of a therapeutic dose without the adverse effects. The anti-nociceptive effects have not yet been reported. In the current study the thermal anti-nociceptive effects of single and multiple oral doses of morphine were assessed. Six horses received a single 0.2 mg/kg IV dose of morphine and multiple oral doses of 0.8 mg/kg morphine every 12 h for 4.5 days. Blood samples were collected throughout administration, morphine, and metabolite concentrations determined and pharmacokinetic analysis performed. Drug related behavior and physiologic responses were recorded. Response to noxious stimuli was evaluated by determining thermal threshold latency in response to the application of heat. The maximum concentrations of M6G were higher following oral administration compared to IV and the combined morphine and M6G concentrations exceeded that of IV administration starting at 2 h. Oral administration of 0.8 mg/kg morphine provided and maintained comparable anti-nociception effects to IV morphine with less adverse effects, following single and multiple doses. Morphine was well tolerated following oral administration with less excitation and minimal effects on gastrointestinal borborygmi scores compared to IV administration. Results of the current study warrant further investigation of the anti-nociceptive effects of oral morphine administration to horses.

Morphine promotes non-small cell lung cancer progression by downregulating E-cadherin via the PI3K/AKT/mTOR pathway

Morphine has been suggested to affect cancer cell dynamics and decrease survival rates in lung cancer patients at specific doses, but the precise mechanisms poorly understood. In this study, we aimed to investigate the molecular mechanisms by which morphine modulates the malignant characteristics of non-small cell lung cancer. Cell proliferation was assessed via the Cell Counting Kit-8 assay, and cell migration and invasion were examined via wound healing and Transwell assays. We employed immunofluorescence staining to evaluate E-cadherin expression in A549 and Lewis lung cancer (LLC) cell lines and immunohistochemistry to evaluate E-cadherin expression in nude mice tumours. Additionally, the in vivo effects of morphine on lung cancer progression were explored in a xenograft tumour experiments, in which naloxone was used as a morphine antagonist. Western blot analysis was performed to detect E-cadherin, phosphorylated mTOR (p-mTOR), mTOR, phosphorylated AKT (p-AKT), AKT, phosphorylated PI3K (p-PI3K), and PI3K protein levels in A549 and LLC cells as well as in tumour samples. Morphine (10 µM) significantly increased the proliferation of A549 and LLC cells in vitro (p < 0.05). It also enhanced the migratory and invasive capacities of these cell lines (p < 0.01). Mechanistically, morphine treatment (10 µM) led to a reduction in the expression of E-cadherin, and an increase in the phosphorylation of PI3K, AKT, and mTOR in A549 and LLC cells (p < 0.01). Morphine treatment (1.5 mg/kg) also reduced E-cadherin expression in xenograft tumours and promoted tumour growth in vivo (p < 0.05). This effect was reversed by naloxone (0.1 mg/kg). The results demonstrated that morphine stimulates the malignant proliferation of A549 and LLC cell lines and promotes xenograft tumour growth. Perhaps by specifically targeting MOR, morphine triggers a signalling cascade that activates the PI3K/AKT/mTOR pathway while inhibiting the EMT marker E-cadherin, which may consequently promote the progression of lung cancer.

Mitragynine and Morphine Produce Dose-dependent Bimodal Action on Food but not Water Intake in Rats.

Novel compounds such as mitragynine, the primary alkaloid in kratom (Mitragyna Speciosa), have emerged as alternative self-treatments for opioid use disorder. Mitragynine binds numerous receptor types, including opioid receptors, which are known to modulate food consumption. However, the ability of acute mitragynine to modulate food consumption remains unknown. The current study assessed the effects of acute mitragynine or morphine administration on unconditioned food and water intake in 16 Sprague Dawley rats. Food and water intake changes were monitored in response to morphine, mitragynine (1.78-56 mg/kg, intraperitoneal), saline, or vehicle controls for 12 hours starting at the onset of the dark cycle. Naltrexone pretreatment was utilized to examine pharmacological specificity. Both morphine and mitragynine demonstrated a biphasic food intake dose-effect, with low doses (5.6 mg/kg) increasing and high doses (56 mg/kg) decreasing food intake. All morphine doses reduced water intake; however, only the highest dose of mitragynine (56 mg/kg) reduced water intake. Naltrexone attenuated both stimulatory and inhibitory effects of morphine on food intake, but only the stimulatory effect of mitragynine. In conclusion, low doses of mitragynine stimulate food intake via opioid-related pathways, while high doses likely recruit other targets.

Simultaneous use of venlafaxine and calcium channel blockers on tolerance to morphine: The role of mitochondrial damage and oxidative stress in the brain

BackgroundOne of the reasons for tolerance to morphine is increased oxidative stress and dysfunction of cell mitochondria in the hippocampus. Venlafaxine and calcium channel blockers can protect mitochondrial function. The investigation of the role of mitochondrial damage and oxidative stress in the simultaneous use of venlafaxine and calcium channel blockers on the acute analgesic effects of morphine and the induction of tolerance to its effects in mice was assessed. MethodIn this experimental study, to induce tolerance to morphine, NMRI mice were treated with 50 mg/kg morphine for three consecutive days and 5 mg/kg morphine on the fourth day. Venlafaxine (20 mg/kg) alone or in combination with calcium channel blockers, nimodipine (10 mg/kg), and diltiazem (40 mg/kg) was administered 30 min before morphine, and the hot plate test was used. Then, hippocampal mitochondria were isolated by differential centrifugation method, and the levels of mitochondrial dehydrogenase activity, mitochondrial membrane potential, mitochondrial ROS production rate, as well as the content of glutathione and malondialdehyde in hippocampal mitochondria, were measured. ResultsThe administration of venlafaxine-nimodipine and venlafaxine-diltiazem increased morphine's acute analgesic effects (P < 0.05) and reduced the induction and expression of tolerance to the analgesic effects of morphine (P < 0.05). Morphine significantly decreased MTT and GSH and increased MDA, mitochondrial membrane damage, and ROS compared to the control group (P < 0.01). Injection of venlafaxine-nimodipine and also venlafaxine-diltiazem 30 min before morphine can improve these alterations (P < 0.05). Discussion and conclusionOur data showed that the simultaneous use of venlafaxine with calcium channel blockers could increase the acute analgesic effects of morphine and reduce the induction and expression of tolerance to it. Also, the preventive and protective roles of simultaneous administration of venlafaxine and calcium channel blockers on morphine-induced mitochondrial oxidative stress and damage during the tolerance test were achieved.

Opioid-environment interaction: Contrasting effects of morphine administered in a novel versus familiar environment on acute and repeated morphine induced behavioral effects and on acute morphine ERK activation in reward associated brain areas

We report that environmental context can have a major impact on morphine locomotor behavior and ERK effects. We manipulated environmental context in terms of an environmental novelty/ familiarity dimension and measured morphine behavioral effects in both acute and chronic morphine treatment protocols. Wistar rats (n=7 per group) were injected with morphine 10 mg/kg or vehicle (s.c.), and immediately placed into an arena for 5 min, and locomotor activity was measured after one or 5 days. The morphine treatments were initiated either when the environment was novel or began after the rats had been familiarized with the arena by being given 5 daily nondrug tests in the arena. The results showed that acute and chronic morphine effects were strongly modified by whether the environment was novel or familiar. Acute morphine administered in a novel environment increased ERK activity more substantially in several brain areas, particularly in reward-associated areas such as the VTA in comparison to when morphine was given in a familiar environment. Repeated morphine treatments initiated in a novel environment induced a strong locomotor sensitization, whereas repeated morphine treatments initiated in a familiar environment did not induce a locomotor stimulant effect but rather a drug discriminative stimulus dis-habituation effect. The marked differential effects of environmental novelty/familiarity and ongoing dopamine activity on acute and chronic morphine treatments may be of potential clinical relevance for opioid drug addiction.

Modulatory Effects of Morphine and Xylopia aethioica Extract on Kappa Opiod Receptors (KOR), Delta Opioid Receptor (DOR), Pain Hypersensitivity and Motor Functions in Wistar Rats

This study investigates the modulatory effects of morphine and Xylopia aethiopica extract on kappa opioid receptors (KOR), delta opioid receptors (DOR), pain hypersensitivity, and motor functions in Wistar rats. We utilized three experimental groups: a control group receiving distilled water, a morphine group receiving either low (5 mg/kg) or high (10 mg/kg) doses after inducing pain, Xylopia aethiopica group received either 25 mg/kg or 50 mg/kg of hydromethanolic extract following similar pain induction. Pain perception was quantified using the tail flick test and Analgesy-Meter while motor functions were assessed through the Rotarod and Climbing/Beam Walk tests. Additionally, molecular docking studies were performed on selected compounds from Xylopia aethiopica to determine their binding affinities to opioid receptors using Vina. Results demonstrated that morphine and Xylopia aethiopica significantly increased tail flick response times, indicating notable analgesic effects, while improving motor functions particularly in animals treated with higher doses of Xylopia aethiopica. Molecular analysis revealed potential interactions between bioactive compounds and opioid receptors, suggesting further therapeutic applications. These findings highlight the potential of Xylopia aethiopica as a natural analgesic and its implications in managing pain and associated motor deficits, the findings further revealed that Morphine and not Xylopia aethiopica is implicated in pain hypersensitivity after long term exposure. Further research should pay attention on improving the pharmacological profiles of the identified compounds for clinical use.

Artemisinin and deoxyartemisinin isolated from Artemisia annua L. promote distinct antinociceptive and anti-inflammatory effects in an animal model

Artemisia annua L., known for antimalarial activity, has demonstrated evidence of anti-inflammatory potential. Previously our research group reported the anti-inflammatory and antinociceptive effect of a sesquiterpene lactone-enriched fraction (Lac-FR) obtained from plant, containing artemisinin and deoxyartemisinin. Both the isolated compounds and Lac-FR evaluated on experimental animal models, in the formalin test showed that deoxyartemisinin reduced both neurogenic pain (56.55 %) and inflammatory pain (45.43 %). These findings were superior to the effect of artemisinin (reduction of 28.66 % and 33.35 %, respectively). In the tail flick test, the antinociceptive effect reported as a percentage of the maximum possible effect (%MPE), deoxyartemisinin showed a lower antinociceptive effect (41.57 %) compared to morphine (75.94 %) in 0.5 h. After 1.5 h, the MPE of deoxyartemisinin (87.99 %) exceeded the effect of morphine (47.55 %), without reversal with naloxone. The MPE of artemisinin (23.3 %) observed after 2 h was lower than deoxiartemisinin, without reversal with the opioid antagonist. Lac-FR and artemisinin demonstrated reductions in ear edema of 43.37 % and 48.19 %, respectively, higher than the effect of deoxyartemisinin (33.64 %). Artemisinin reduced tumor necrosis factor alpha (TNF-α) (76.96 %) more selectively when compared to interleukin-1beta (IL-1β) (48.23 %) and interleukin-6 (IL-6) (44.49 %). Lac-FR showed greater selectivity in IL-6 reduction (56.49 %) in relationship to TNF-α (46.71 %) and IL-1β (45.12 %), whereas deoxyartemisinin selectively reduced TNF-α (37.37 %). The results of our study indicate that the lactones isolated did not have relationship with the opioid system. Deoxyartemisinin showed a higher antinociceptive potential than artemisinin. Whereas, artemisinin showed a higher reduction of inflammation and mediators, with a better anti-inflammatory activity outcome.

Preparation and Evaluation of the In situ Gel-forming Chitosan Hydrogels for Nasal Delivery of Morphine in a Single Unit dose in Rats to Enhance the Analgesic Responses.

In this study, an in situ gel-forming chitosan hydrogel was prepared with the use of glutamate salt of chitosan (Ch-Ga), β-glycerophosphate (Gp), and morphine (Mor). The paper is focused on in vitro physicochemical properties and in-vivo analgesic effects of the prepared chitosan hydrogel. The thermosensitive properties of prepared chitosan hydrogel were evaluated during the different temperatures and times. The physicochemical properties of chitosan hydrogel were investigated by infrared (IR) spectroscopy and X-ray diffraction analysis (XRD). Also, its cell cytotoxicity effects were evaluated in murine NIH/3T3 normal cells. Subsequently, the distribution of chitosan hydrogel in the nasal cavity of rats and its analgesic responses were evaluated. The prepared chitosan hydrogel showed that it could be gelled at the temperature of 34 °C before leaving the nose in the shortest possible time of 30 s. The analgesic responses of the intranasal (IN) injection of chitosan hydrogel (IN-chitosan hydrogel, 10 mg Mor/kg) in a single unit dose in rat relative to the placebo and intranasal or intraperitoneal (IP) injection of free morphine solution (IN-Free Mor or IP-Free Mor, 10 mg Mor/kg) via the hot plate test, reveal that the IN-chitosan hydrogel could induce fast analgesic effects of morphine with maximum possible effect (MPE) of 93% after 5 min compare to the IN-Free Mor and IP-Free Mor with MPE of 80% after 15 min and 66% after 30 min, respectively. Also, prolonged analgesic effects with MPE of 78 % after 6 h of injection were only seen in the IN-chitosan hydrogel injected group. The obtained fluorescent images of rat's brain injected with IN-chitosan hydrogel containing doxorubicine (Dox) as a fluorescent agent showed that the mucosal adhesive and absorption enhancer properties of IN-chitosan hydrogel resulting in longer presence of them in the nasal cavity of rats followed by more absorption of Dox from the blood vessels of olfactory bulbs with a 74% color intensity compared to the IN-Free Mor and IN-Free Dox with 15%. These data reveal that the IN-chitosan hydrogel could induce fast and prolonged analgesic effects of morphine compare to the IN/IP-Free Mor, which could be considered as an in situ gel-forming thermosensitive chitosan hydrogel for nasal delivery of wide ranges of therapeutic agents.

Opioid free analgesia after return home in ambulatory colonic surgery patients: a single-center observational study

BackgroundBecause of the adverse effects of morphine and its derivatives, non-opioid analgesia procedures are proposed after outpatient surgery. Without opioids, the ability to provide quality analgesia after the patient returns home may be questioned. We examined whether an opioid-free strategy could ensure satisfactory analgesia after ambulatory laparoscopic colectomy.MethodsWe performed a retrospective observational single-center study (of prospective collected database) including all patients eligible for scheduled outpatient colectomy. Postoperative analgesia was provided by paracetamol and nefopam. Postoperative follow-up included pain at mobilization (assessed by a numerical rating scale, NRS), hemodynamic variables, temperature, resumption of transit and biological markers of postoperative inflammation. The primary outcome was the proportion of patients with moderate to severe pain (NRS > 4) the day after surgery.ResultsData from 144 patients were analyzed. The majority were men aged 59 ± 12 years with a mean BMI of 27 [25-30] kg/m2. ASA scores were 1 for 14%, 2 for 59% and 3 for 27% of patients. Forty-seven patients (33%) underwent surgery for cancer, 94 for sigmoiditis (65%) and 3 (2%) for another colonic pathology. Postoperative pain was affected by time since surgery (Q3 = 52.4,p < 0.001) and decreased significantly from day to day. The incidence of moderate to severe pain at mobilization (NRS > 4) on the first day after surgery was (0.19; 95% CI, 0.13–0.27).ConclusionNon-opioid analgesia after ambulatory laparoscopic colectomy seems efficient to ensure adequate analgesia. This therapeutic strategy makes it possible to avoid the adverse effects of opioids.Trial registrationThe study was retrospectively registered and approved by the relevant institutional review board (CERAR) reference IRB 00010254–2018 – 188). All patients gave written informed consent for analysis of their data. The anonymous database was declared to the French Data Protection Authority (CNIL) (reference 221 2976 v0 of April 12, 2019).

The Effects of Eating a Traditional High Fat/High Carbohydrate or a Ketogenic Diet on Sensitivity of Female Rats to Morphine.

Patients diagnosed with obesity are prescribed opioid medications at a higher rate than the general population; however, it is not known if eating a high fat diet might impact individual sensitivity to these medications. To explore the hypothesis that eating a high fat diet increases sensitivity of rats to the effects of morphine, 24 female Sprague-Dawley rats (n = 8/diet) ate either a standard (low fat) laboratory chow (17% kcal from fat), a high fat/low carbohydrate (ketogenic) chow (90.5% kcal from fat), or a traditional high fat/high carbohydrate chow (60% kcal from fat). Morphine-induced antinociception was assessed using a warm water tail withdrawal procedure, during which latency (in seconds) for rats to remove their tail from warm water baths was recorded following saline or morphine (0.32-56 mg/kg, i.p.) injections. Morphine was administered acutely and chronically (involving 18 days of twice-daily injections, increasing in 1/4 log dose increments every 3 days: 3.2-56 mg/kg, i.p., to induce dependence and assess tolerance). The adverse effects of morphine (i.e., tolerance, withdrawal, and changes in body temperature) were assessed throughout the study. Acute morphine induced comparable antinociception in rats eating different diets, and all rats developed tolerance following chronic morphine exposure. Observable withdrawal signs and body temperature were also comparable among rats eating different diets; however, withdrawal-induced weight loss was less severe for rats eating ketogenic chow. These results suggest that dietary manipulation might modulate the severity of withdrawal-related weight loss in ways that could be relevant for patients.

M52 - Effects of Cannabidiol and Morphine on Antinociception Across Multiple Modalities

M52 - Effects of Cannabidiol and Morphine on Antinociception Across Multiple Modalities

Baclofen prevents morphine rewarding effects and associated biochemical alterations in male and female mice

Previous studies from our laboratory have shown sex differences in the behavioral, molecular, and neurochemical manifestations of morphine withdrawal and they were related to an increased sensitivity to morphine effects in males. In addition, we observed an interaction between the GABAergic and opioid systems that could also be sex-dependent. Baclofen, a GABAB receptor agonist, prevented the somatic expression and the molecular and neurochemical changes induced by morphine withdrawal syndrome in mice. On the contrary, little is known about baclofen effects in the rewarding properties of morphine in male and female mice. The present study aimed to explore the effect of baclofen (1, 2 and 3 mg/kg, i.p.) pretreatment in the rewarding effects induced by morphine (7 mg/kg, s.c.) and its effect on c-Fos and brain-derived neurotrophic factor (BDNF) expression induced by the rewarding properties of morphine in prepubertal male and female mice. Baclofen (2 mg/kg) pretreatment prevented the rewarding effects of morphine only in male mice, while baclofen (3 mg/kg) reduced these effects in both sexes. Moreover, the rewarding effects of morphine were associated with a decrease of BDNF and c-Fos expression cingulate cortex, nucleus accumbens shell, cornu ammonis 1 (CA1), and cornu ammonis 3 (CA3) areas of the hippocampus only in male mice. In addition, baclofen pretreatment prevented these changes in BDNF, but not in c-Fos expression. In conclusion, our results show that GABAB receptors have a regulatory role in the rewarding effects of morphine that could be of interest for a potential future therapeutic application in opioid use disorders.

Postoperative Cesarean Section Pain Management Using Transversus Abdominis Plane Block Versus Intrathecal Morphine: A Systematic Review and Meta-analysis

PurposeCompare and evaluate the effectiveness of transversus abdominis plane (TAP) block versus intrathecal morphine (ITM) on elective postcesarean section pain, opioid consumption, and related side effects. DesignSystematic review and meta-analysis. MethodsA search for evidence was conducted in PubMed, Google Scholar, CINAHL, Cochrane Collaboration Database, UpToDate, Health Source, and gray literature. Only randomized controlled trials (RCTs) were included in the study. The methodological quality of evidence assessment was conducted using the Risk of Bias and Grades of Recommendation, Assessment, Development, and Evaluation system. The meta-analysis used Review Manager (RevMan 5.4, The Cochrane Collaboration). FindingsA total of 11 RCTs involving 1,129 patients were analyzed. Compared to ITM, TAP has a similar effect on static (mean difference [MD]; 0.37; 95% confidence interval [CI], −0.04 to 0.79; P = .08) and dynamic pain scores (MD, 0.43; 95% CI, −0.06 to 0.92; P = .09) within the first 48 hours after surgery. Additionally, the TAP block had a lower incidence of postoperative nausea and vomiting (risk ratio, 0.45; 95% CI, 0.31 to 0.66; P < .0001) and increased opioid consumption (MD, 6.78; 95% CI, 3.79 to 9.77; P < .00001). Overall, TAP block and ITM did not differ in the time to first to rescue analgesia, incidence of sedation, and pruritus. ConclusionsEvidence suggests that TAP blocks are equivalent to ITM in pain scores and more effective at lowering the incidence of postoperative nausea and vomiting, yet ITM has been shown to be more effective in reducing postoperative opioid consumption.