Unique, Specific CART Receptor-Independent Regulatory Mechanism of CART(55-102) Peptide in Spinal Nociceptive Transmission and Its Relation to Dipeptidyl-Peptidase 4 (DDP4).

Cocaine- and amphetamine-regulated transcript (CART) peptides are involved in several physiological and pathological processes, but their mechanism of action is unrevealed due to the lack of identified receptor(s). We provided evidence for the antihyperalgesic effect of CART(55-102) by inhibiting dipeptidyl-peptidase 4 (DPP4) in astrocytes and consequently reducing neuroinflammation in the rat spinal dorsal horn in a carrageenan-evoked inflammation model. Both naturally occurring CART(55-102) and CART(62-102) peptides are present in the spinal cord. CART(55-102) is not involved in acute nociception but regulates spinal pain transmission during peripheral inflammation. While the full-length peptide with a globular motif contributes to hyperalgesia, its N-terminal inhibits this process. Although the anti-hyperalgesic effects of CART(55-102), CART(55-76), and CART(62-76) are blocked by opioid receptor antagonists in our inflammatory models, but not in neuropathic Seltzer model, none of them bind to any opioid or G-protein coupled receptors. DPP4 interacts with Toll-like receptor 4 (TLR4) signalling in spinal astrocytes and enhances the TLR4-induced expression of interleukin-6 and tumour necrosis factor alpha contributing to inflammatory pain. Depending on the state of inflammation, CART(55-102) is processed in the spinal cord, resulting in the generation of biologically active isoleucine-proline-isoleucine (IPI) tripeptide, which inhibits DPP4, leading to significantly decreased glia-derived cytokine production and hyperalgesia.

Telmisartan Is a Promising Agent for Managing Neuropathic Pain and Delaying Opioid Analgesic Tolerance in Rats.

Despite the large arsenal of analgesic medications, neuropathic pain (NP) management is not solved yet. Angiotensin II receptor type 1 (AT1) has been identified as a potential target in NP therapy. Here, we investigate the antiallodynic effect of AT1 blockers telmisartan and losartan, and particularly their combination with morphine on rat mononeuropathic pain following acute or chronic oral administration. The impact of telmisartan on morphine analgesic tolerance was also assessed using the rat tail-flick assay. Morphine potency and efficacy in spinal cord samples of treated neuropathic animals were assessed by [35S]GTPγS-binding assay. Finally, the glutamate content of the cerebrospinal fluid (CSF) was measured by capillary electrophoresis. Oral telmisartan or losartan in higher doses showed an acute antiallodynic effect. In the chronic treatment study, the combination of subanalgesic doses of telmisartan and morphine ameliorated allodynia and resulted in a leftward shift in the dose-response curve of morphine in the [35S]GTPγS binding assay and increased CSF glutamate content. Telmisartan delayed morphine analgesic-tolerance development. Our study has identified a promising combination therapy composed of telmisartan and morphine for NP and opioid tolerance. Since telmisartan is an inhibitor of AT1 and activator of PPAR-γ, future studies are needed to analyze the effect of each component.

Insights into the Current and Possible Future Use of Opioid Antagonists in Relation to Opioid-Induced Constipation and Dysbiosis.

Opioid receptor agonists, particularly those that activate µ-opioid receptors (MORs), are essential analgesic agents for acute or chronic mild to severe pain treatment. However, their use has raised concerns including, among others, intestinal dysbiosis. In addition, growing data on constipation-evoked intestinal dysbiosis have been reported. Opioid-induced constipation (OIC) creates an obstacle to continuing treatment with opioid analgesics. When non-opioid therapies fail to overcome the OIC, opioid antagonists with peripheral, fast first-pass metabolism, and gastrointestinal localized effects remain the drug of choice for OIC, which are discussed here. At first glance, their use seems to only be restricted to constipation, however, recent data on OIC-related dysbiosis and its contribution to the appearance of several opioid side effects has garnered a great of attention from researchers. Peripheral MORs have also been considered as a future target for opioid analgesics with limited central side effects. The properties of MOR antagonists counteracting OIC, and with limited influence on central and possibly peripheral MOR-mediated antinociception, will be highlighted. A new concept is also proposed for developing gut-selective MOR antagonists to treat or restore OIC while keeping peripheral antinociception unaffected. The impact of opioid antagonists on OIC in relation to changes in the gut microbiome is included.

The Acute Antiallodynic Effect of Tolperisone in Rat Neuropathic Pain and Evaluation of Its Mechanism of Action.

Current treatment approaches to manage neuropathic pain have a slow onset and their use is largely hampered by side-effects, thus there is a significant need for finding new medications. Tolperisone, a centrally acting muscle relaxant with a favorable side effect profile, has been reported to affect ion channels, which are targets for current first-line medications in neuropathic pain. Our aim was to explore its antinociceptive potency in rats developing neuropathic pain evoked by partial sciatic nerve ligation and the mechanisms involved. Acute oral tolperisone restores both the decreased paw pressure threshold and the elevated glutamate level in cerebrospinal fluid in neuropathic rats. These effects were comparable to those of pregabalin, a first-line medication in neuropathy. Tolperisone also inhibits release of glutamate from rat brain synaptosomes primarily by blockade of voltage-dependent sodium channels, although inhibition of calcium channels may also be involved at higher concentrations. However, pregabalin fails to affect glutamate release under our present conditions, indicating a different mechanism of action. These results lay the foundation of the avenue for repurposing tolperisone as an analgesic drug to relieve neuropathic pain.

Pharmacological Evidence on Augmented Antiallodynia Following Systemic Co-Treatment with GlyT-1 and GlyT-2 Inhibitors in Rat Neuropathic Pain Model.

The limited effect of current medications on neuropathic pain (NP) has initiated large efforts to develop effective treatments. Animal studies showed that glycine transporter (GlyT) inhibitors are promising analgesics in NP, though concerns regarding adverse effects were raised. We aimed to study NFPS and Org-25543, GlyT-1 and GlyT-2 inhibitors, respectively and their combination in rat mononeuropathic pain evoked by partial sciatic nerve ligation. Cerebrospinal fluid (CSF) glycine content was also determined by capillary electrophoresis. Subcutaneous (s.c.) 4 mg/kg NFPS or Org-25543 showed analgesia following acute administration (30-60 min). Small doses of each compound failed to produce antiallodynia up to 180 min after the acute administration. However, NFPS (1 mg/kg) produced antiallodynia after four days of treatment. Co-treatment with subanalgesic doses of NFPS (1 mg/kg) and Org-25543 (2 mg/kg) produced analgesia at 60 min and thereafter meanwhile increased significantly the CSF glycine content. This combination alleviated NP without affecting motor function. Test compounds failed to activate G-proteins in spinal cord. To the best of our knowledge for the first time we demonstrated augmented analgesia by combining GlyT-1 and 2 inhibitors. Increased CSF glycine content supports involvement of glycinergic system. Combining selective GlyT inhibitors or developing non-selective GlyT inhibitors might have therapeutic value in NP.

Shedding Light on the Pharmacological Interactions between µ-Opioid Analgesics and Angiotensin Receptor Modulators: A New Option for Treating Chronic Pain.

The current protocols for neuropathic pain management include µ-opioid receptor (MOR) analgesics alongside other drugs; however, there is debate on the effectiveness of opioids. Nevertheless, dose escalation is required to maintain their analgesia, which, in turn, contributes to a further increase in opioid side effects. Finding novel approaches to effectively control chronic pain, particularly neuropathic pain, is a great challenge clinically. Literature data related to pain transmission reveal that angiotensin and its receptors (the AT1R, AT2R, and MAS receptors) could affect the nociception both in the periphery and CNS. The MOR and angiotensin receptors or drugs interacting with these receptors have been independently investigated in relation to analgesia. However, the interaction between the MOR and angiotensin receptors has not been excessively studied in chronic pain, particularly neuropathy. This review aims to shed light on existing literature information in relation to the analgesic action of AT1R and AT2R or MASR ligands in neuropathic pain conditions. Finally, based on literature data, we can hypothesize that combining MOR agonists with AT1R or AT2R antagonists might improve analgesia.

Comparisons of In Vivo and In Vitro Opioid Effects of Newly Synthesized 14-Methoxycodeine-6-O-sulfate and Codeine-6-O-sulfate.

The present work represents the in vitro (potency, affinity, efficacy) and in vivo (antinociception, constipation) opioid pharmacology of the novel compound 14-methoxycodeine-6-O-sulfate (14-OMeC6SU), compared to the reference compounds codeine-6-O-sulfate (C6SU), codeine and morphine. Based on in vitro tests (mouse and rat vas deferens, receptor binding and [35S]GTPγS activation assays), 14-OMeC6SU has µ-opioid receptor-mediated activity, displaying higher affinity, potency and efficacy than the parent compounds. In rats, 14-OMeC6SU showed stronger antinociceptive effect in the tail-flick assay than codeine and was equipotent to morphine, whereas C6SU was less efficacious after subcutaneous (s.c.) administration. Following intracerebroventricular injection, 14-OMeC6SU was more potent than morphine. In the Complete Freund's Adjuvant-induced inflammatory hyperalgesia, 14-OMeC6SU and C6SU in s.c. doses up to 6.1 and 13.2 µmol/kg, respectively, showed peripheral antihyperalgesic effect, because co-administered naloxone methiodide, a peripherally acting opioid receptor antagonist antagonized the measured antihyperalgesia. In addition, s.c. C6SU showed less pronounced inhibitory effect on the gastrointestinal transit than 14-OMeC6SU, codeine and morphine. This study provides first evidence that 14-OMeC6SU is more effective than codeine or C6SU in vitro and in vivo. Furthermore, despite C6SU peripheral antihyperalgesic effects with less gastrointestinal side effects the superiority of 14-OMeC6SU was obvious throughout the present study.

On the Role of Peripheral Sensory and Gut Mu Opioid Receptors: Peripheral Analgesia and Tolerance.

There is growing evidence on the role of peripheral µ-opioid receptors (MORs) in analgesia and analgesic tolerance. Opioid analgesics are the mainstay in the management of moderate to severe pain, and their efficacy in the alleviation of pain is well recognized. Unfortunately, chronic treatment with opioid analgesics induces central analgesic tolerance, thus limiting their clinical usefulness. Numerous molecular mechanisms, including receptor desensitization, G-protein decoupling, ß-arrestin recruitment, and alterations in the expression of peripheral MORs and microbiota have been postulated to contribute to the development of opioid analgesic tolerance. However, these studies are largely focused on central opioid analgesia and tolerance. Accumulated literature supports that peripheral MORs mediate analgesia, but controversial results on the development of peripheral opioid receptors-mediated analgesic tolerance are reported. In this review, we offer evidence on the consequence of the activation of peripheral MORs in analgesia and analgesic tolerance, as well as approaches that enhance analgesic efficacy and decrease the development of tolerance to opioids at the peripheral sites. We have also addressed the advantages and drawbacks of the activation of peripheral MORs on the sensory neurons and gut (leading to dysbiosis) on the development of central and peripheral analgesic tolerance.

Chemically Modified Derivatives of the Activator Compound Cloxyquin Exert Inhibitory Effect on TRESK (K2P18.1) Background Potassium Channel.

Cloxyquin has been reported as a specific activator of TRESK [TWIK-related spinal cord K+ channel (also known as K2P18.1)] background potassium channel. In this study, we have synthetized chemically modified analogs of cloxyquin and tested their effects on TRESK and other K2P channels. The currents of murine K2P channels, expressed heterologously in Xenopus oocytes, were measured by two-electrode voltage clamp, whereas the native background K+ conductance of mouse dorsal root ganglion (DRG) neurons was examined by the whole-cell patch-clamp method. Some of the analogs retained the activator character of the parent compound, but, more interestingly, other derivatives inhibited mouse TRESK current. The inhibitor analogs (A2764 and A2793) exerted state-dependent effects. The degree of inhibition by 100 µM A2764 (77.8% ± 3.5%, n = 6) was larger in the activated state of TRESK (i.e., after calcineurin-dependent stimulation) than in the resting state of the channel (42.8% ± 11.5% inhibition, n = 7). The selectivity of the inhibitor compounds was tested on several K2P channels. A2793 inhibited TWIK-related acid-sensitive K+ channel (TASK)-1 (100 µM, 53.4% ± 13, 5%, n = 5), while A2764 was more selective for TRESK, it only moderately influenced TREK-1 and TWIK-related alkaline pH-activated K+ channel. The effect of A2764 was also examined on the background K+ currents of DRG neurons. A subpopulation of DRG neurons, prepared from wild-type animals, expressed background K+ currents sensitive to A2764, whereas the inhibitor did not affect the currents in the DRG neurons of TRESK-deficient mice. Accordingly, A2764 may prove to be useful for the identification of TRESK current in native cells, and for the investigation of the role of the channel in nociception and migraine. SIGNIFICANCE STATEMENT: TRESK background potassium channel is a potential pharmacological target in migraine and neuropathic pain. In this study, we have identified a selective inhibitor of TRESK, A2764. This compound can inhibit TRESK in native cells, leading to cell depolarization and increased excitability. This new inhibitor may be of use to probe the role of TRESK channel in migraine and nociception.

New Morphine Analogs Produce Peripheral Antinociception within a Certain Dose Range of Their Systemic Administration.

Growing data support peripheral opioid antinociceptive effects, particularly in inflammatory pain models. Here, we examined the antinociceptive effects of subcutaneously administered, recently synthesized 14-O-methylmorphine-6-O-sulfate (14-O-MeM6SU) compared with morphine-6-O-sulfate (M6SU) in a rat model of inflammatory pain induced by an injection of complete Freund's adjuvant and in a mouse model of visceral pain evoked by acetic acid. Subcutaneous doses of 14-O-MeM6SU and M6SU up to 126 and 547 nmol/kg, respectively, produced significant and subcutaneous or intraplantar naloxone methiodide (NAL-M)-reversible antinociception in inflamed paws compared with noninflamed paws. Neither of these doses significantly affected thiobutabarbital-induced sleeping time or rat pulmonary parameters. However, the antinociceptive effects of higher doses were only partially reversed by NAL-M, indicating contribution of the central nervous system. In the mouse writhing test, 14-O-MeM6SU was more potent than M6SU after subcutaneous or intracerebroventricular injections. Both displayed high subcutaneous/intracerebroventricular ED50 ratios. The antinociceptive effects of subcutaneous 14-O-MeM6SU and M6SU up to 136 and 3043 nmol/kg, respectively, were fully antagonized by subcutaneous NAL-M. In addition, the test compounds inhibited mouse gastrointestinal transit in antinociceptive doses. Taken together, these findings suggest that systemic administration of the novel compound 14-O-MeM6SU similar to M6SU in specific dose ranges shows peripheral antinociception in rat and mouse inflammatory pain models without central adverse effects. These findings apply to male animals and must be confirmed in female animals. Therefore, titration of systemic doses of opioid compounds with limited access to the brain might offer peripheral antinociception of clinical importance.

Central P2Y12 receptor blockade alleviates inflammatory and neuropathic pain and cytokine production in rodents.

In this study the role of P2Y12 receptors (P2Y12R) was explored in rodent models of inflammatory and neuropathic pain and in acute thermal nociception. In correlation with their activity to block the recombinant human P2Y12R, the majority of P2Y12R antagonists alleviated mechanical hyperalgesia dose-dependently, following intraplantar CFA injection, and after partial ligation of the sciatic nerve in rats. They also caused an increase in thermal nociceptive threshold in the hot plate test. Among the six P2Y12R antagonists evaluated in the pain studies, the selective P2Y12 receptor antagonist PSB-0739 was most potent upon intrathecal application. P2Y12R mRNA and IL-1ß protein were time-dependently overexpressed in the rat hind paw and lumbar spinal cord following intraplantar CFA injection. This was accompanied by the upregulation of TNF-α, IL-6 and IL-10 in the hind paw. PSB-0739 (0.3mg/kg i.t.) attenuated CFA-induced expression of cytokines in the hind paw and of IL-1ß in the spinal cord. Subdiaphragmatic vagotomy and the α7 nicotinic acetylcholine receptor antagonist MLA occluded the effect of PSB-0739 (i.t.) on pain behavior and peripheral cytokine induction. Denervation of sympathetic nerves by 6-OHDA pretreatment did not affect the action of PSB-0739. PSB-0739, in an analgesic dose, did not influence motor coordination and platelet aggregation. Genetic deletion of the P2Y12R in mice reproduced the effect of P2Y12R antagonists on mechanical hyperalgesia in inflammatory and neuropathic pain models, on acute thermal nociception and on the induction of spinal IL-1ß. Here we report the robust involvement of the P2Y12R in inflammatory pain. The anti-hyperalgesic effect of P2Y12R antagonism could be mediated by the inhibition of both central and peripheral cytokine production and involves α7-receptor mediated efferent pathways.

[Behavioural studies during the gestational-lactation period in morphine treated rats]. / Viselkedési vizsgálatok a gesztációs-laktációs idoszakban morfin-kezelt patkányon.

UNLABELLED: Opioids impair the maternal behaviour of experimental animals. The effect of morphine on maternal behaviour in rat dams treated chronically with morphine during the whole pregnancy and lactation has not been yet analysed systematically. OBJECTIVE: The aim of our work was to investigate the behavioural effects of moderate dose morphine administered constantly in the whole perinatal period in rats. METHODS: Nulliparous female rats were treated with 10 mg/kg morphine s.c. once daily, from the day of mating. Maternal behaviour was observed, the effects of acute morphine treatment on the maternal behaviour and whether this effect could be antagonised by naloxone were also investigated. Physical and other behavioural (anxiety-like signals in elevated plus maze, changes in locomotor activity) withdrawal signs precipitated by naloxone were registered. After weaning sensitivity to the rewarding effect of morphine was measured by conditioned place preference and to the aversive effect of naloxone by conditioned place aversion tests. Antinociceptive test on tail-flick apparatus was performed to investigate the changes in morphine antinociceptive effects due to chronic morphine treatment. RESULTS: Maternal behaviour was significantly impaired in morphine-treated dams. This effect of morphine lasted c.a. 2-3 hours a day, it showed dose-dependency and was enhanced in MO-treated group (sensitisation). Only weak physical and no other behavioural (anxiety-like behaviour or hypolocomotion) withdrawal signs were precipitated by naloxone. The positive reinforcing effect of morphine and aversive effect of naloxone were markedly increased on conditioned place paradigm. Significant antinociceptive tolerance was not seen. CONCLUSION: Although human drug abuse can be hardly modelling under experimental circumstances, our constant, relatively moderate dose morphine treatment administered once daily during the whole pregnancy and lactation resulted in several subtle behavioural changes in dams. In perinatally opioid-exposed offspring short- and long-term behavioural disturbances can be detected which is well-known from literature. Besides direct pharmacological effects of morphine impaired maternal responsiveness and pup care could play a role in these disturbances.

Interactions between NSAIDs, opioids and the gut microbiota - Future perspectives in the management of inflammation and pain.

The composition of intestinal microbiota is influenced by a number of factors, including medications, which may have a substantial impact on host physiology. Nonsteroidal anti-inflammatory drugs (NSAIDs) and opioid analgesics are among those widely used medications that have been shown to alter microbiota composition in both animals and humans. Although much effort has been devoted to identify microbiota signatures associated with these medications, much less is known about the underlying mechanisms. Mucosal inflammation, changes in intestinal motility, luminal pH and bile acid metabolism, or direct drug-induced inhibitory effect on bacterial growth are all potential contributors to NSAID- and opioid-induced dysbiosis, however, only a few studies have addressed directly these issues. In addition, there is a notable overlap between the microbiota signatures of these drugs and certain diseases in which they are used, such as spondyloarthritis (SpA), rheumatoid arthritis (RA) and neuropathic pain associated with type 2 diabetes (T2D). The aims of the present review are threefold. First, we aim to provide a comprehensive up-to-date summary on the bacterial alterations caused by NSAIDs and opioids. Second, we critically review the available data on the possible underlying mechanisms of dysbiosis. Third, we review the current knowledge on gut dysbiosis associated with SpA, RA and neuropathic pain in T2D, and highlight the similarities between them and those caused by NSAIDs and opioids. We posit that drug-induced dysbiosis may contribute to the persistence of these diseases, and may potentially limit the therapeutic effect of these medications by long-term use. In this context, we will review the available literature data on the effect of probiotic supplementation and fecal microbiota transplantation on the therapeutic efficacy of NSAIDs and opioids in these diseases.

Pregabalin-Tolperisone Combination to Treat Neuropathic Pain: Improved Analgesia and Reduced Side Effects in Rats.

The current treatment of neuropathic pain (NP) is unsatisfactory; therefore, effective novel agents or combination-based analgesic therapies are needed. Herein, oral tolperisone, pregabalin, and duloxetine were tested for their antinociceptive effect against rat partial sciatic nerve ligation (pSNL)-induced tactile allodynia described by a decrease in the paw withdrawal threshold (PWT) measured by a dynamic plantar aesthesiometer. On day 7 after the operation, PWTs were assessed at 60, 120, and 180 min post-treatment. Chronic treatment was continued for 2 weeks, and again, PWTs were measured on day 14 and 21. None of the test compounds produced an acute antiallodynic effect. In contrast, after chronic treatment, tolperisone and pregabalin alleviated allodynia. In other experiments, on day 14, the acute antiallodynic effect of the tolperisone/pregabalin or duloxetine combination was measured. As a novel finding, a single dose of the tolperisone/pregabalin combination could remarkably alleviate allodynia acutely. It also restored the neuropathy-induced elevated CSF glutamate content. Furthermore, the combination is devoid of adverse effects related to motor and gastrointestinal transit functions. Tolperisone and pregabalin target voltage-gated sodium and calcium channels, respectively. The dual blockade effect of the combination might explain its advantageous acute analgesic effect in the present work.

Recent Molecular Insights into Agonist-specific Binding to the Mu-Opioid Receptor.

Opioid agonists produce their analgesic effects primarily by acting at the µ-opioid receptor (µOR). µOR agonists with different efficacies exert diverse molecular changes in the µOR which dictate the faith of the receptor's signaling pathway and possibly it's the degree of desensitization. Since the development of the active conformations of the µOR, growing data have been published in relation to ligand-specific changes in µOR activation. In this regard, this review summarizes recent data regarding the most studied opioid agonists in in silico µOR activation, including how these ligands are recognized by the µOR, how their binding signal is transmitted toward the intracellular parts of the µOR, and finally, what type of large-scale movements do these changes trigger in the µOR's domains.

Role of faith in strategies of healthcare professionals in intensive care units in end-of-life decision making / A vallásosság szerepe az intenzív osztályon dolgozó orvosok és ápolók véleményének kialakításában az életvégi döntések meghozatalakor.

Összefoglaló. Bevezetés: A haldoklást minden korban kulturális és vallási szabályok vették körül, melyek a mai napig hatnak a társadalomban. A 21. században számos beteg a kórházban, az intenzív osztályon fejezi be életét, ahol nem ritkán kerülhet sor életvégi döntés meghozatalára. Célkituzés: Vizsgálatunk célja annak feltárása volt, milyen hatással van az orvosok és ápolók vallásossága a kezeléskorlátozással kapcsolatos döntésekre az intenzív osztályon. Módszer: Magyarországi intenzív osztályokon dolgozó orvosok és szakdolgozók körében végeztünk kérdoíves felmérést a vallás életvégi döntésekre gyakorolt hatásáról. 189 orvos és 105 ápoló által anonim módon kitöltött kérdoívet elemeztünk. Eredmények: Az intenzív osztályra történo betegfelvételre nem volt hatással a vallásosság, azonban a szabad ágyak száma a vallásos orvosokat erosebben befolyásolta, mint az ateista és választ nem adó orvosokat (<0,0001). A vallásukat gyakorló orvosok szignifikánsan jobban figyelembe vették a hozzátartozó kérését, mint az ateisták (p = 0,0002). A vallásos ápolók gyakrabban folytatnák a beteg kezelését a hozzátartozó kérése ellenére is, ha még látnának esélyt a gyógyulásra, mint a nem vallásosak. Következtetés: Vizsgálatunk alátámasztotta, hogy a világnézet befolyásolja az orvosokat és ápolókat az élet végérol hozott döntésekben. A kezeléskorlátozásról hozott döntés összetett, elengedhetetlen megismerni hozzá a beteg és családjának haldoklással kapcsolatos vallási szokásait, mivel jó életvégi döntés a világnézeti szempontok figyelembevétele nélkül nem hozható. Orv Hetil. 2021; 162(51): 2047-2054. INTRODUCTION: Death has always been surrounded by habits in all ages, influenced by cultural and religious differences. Many patients finish their lives at intensive care units where end-of-life decisions are the part of everyday practice in the 21th century. OBJECTIVE: The goal of our study was to assess how the religious beliefs of physicians and nurses affect their decision on therapy restriction. METHOD: We have performed questionnaire-based enquiries among physicians and nurses working at intensive care units on how religion affects end-of-life decisions. We have analyzed the anonymous questionnaires filled out by 189 physicians and 105 nurses. RESULTS: Our results have confirmed the hypothesis that religion affects decision making about therapy restriction. Patients' admissions were not affected by religious beliefs, but the number of available patient beds influenced the religious physicians more than the atheists ones or the non-responders (<0.0001). Actively religious physicians complied significantly better with the relatives than atheists (p = 0.0002). Religious nurses would continue patient treatment even against the will of relatives more often than atheists if they see a chance for recovery. CONCLUSION: The study supports that religion influences physicians and nurses in their end-of-life decisions. Decisions on therapy restriction are complex; it is important to find out religious beliefs and perception of death among patients and families because good end-of-life decision cannot be made disregarding religious considerations. Orv Hetil. 2021; 162(51): 2047-2054.

The Nonsteroidal Anti-Inflammatory Drug Ketorolac Alters the Small Intestinal Microbiota and Bile Acids Without Inducing Intestinal Damage or Delaying Peristalsis in the Rat.

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) induce significant damage to the small intestine, which is accompanied by changes in intestinal bacteria (dysbiosis) and bile acids. However, it is still a question of debate whether besides mucosal inflammation also other factors, such as direct antibacterial effects or delayed peristalsis, contribute to NSAID-induced dysbiosis. Here we aimed to assess whether ketorolac, an NSAID lacking direct effects on gut bacteria, has any significant impact on intestinal microbiota and bile acids in the absence of mucosal inflammation. We also addressed the possibility that ketorolac-induced bacterial and bile acid alterations are due to a delay in gastrointestinal (GI) transit. Methods: Vehicle or ketorolac (1, 3 and 10 mg/kg) were given to rats by oral gavage once daily for four weeks, and the severity of mucosal inflammation was evaluated macroscopically, histologically, and by measuring the levels of inflammatory proteins and claudin-1 in the distal jejunal tissue. The luminal amount of bile acids was measured by liquid chromatography-tandem mass spectrometry, whereas the composition of microbiota by sequencing of bacterial 16S rRNA. GI transit was assessed by the charcoal meal method. Results: Ketorolac up to 3 mg/kg did not cause any signs of mucosal damage to the small intestine. However, 3 mg/kg of ketorolac induced dysbiosis, which was characterized by a loss of families belonging to Firmicutes (Paenibacillaceae, Clostridiales Family XIII, Christensenellaceae) and bloom of Enterobacteriaceae. Ketorolac also changed the composition of small intestinal bile by decreasing the concentration of conjugated bile acids and by increasing the amount of hyodeoxycholic acid (HDCA). The level of conjugated bile acids correlated negatively with the abundance of Erysipelotrichaceae, Ruminococcaceae, Clostridiaceae 1, Muribaculaceae, Bacteroidaceae, Burkholderiaceae and Bifidobacteriaceae. Ketorolac, under the present experimental conditions, did not change the GI transit. Conclusion: This is the first demonstration that low-dose ketorolac disturbed the delicate balance between small intestinal bacteria and bile acids, despite having no significant effect on intestinal mucosal integrity and peristalsis. Other, yet unidentified, factors may contribute to ketorolac-induced dysbiosis and bile dysmetabolism.

A comprehensive time course and correlation analysis of indomethacin-induced inflammation, bile acid alterations and dysbiosis in the rat small intestine.

It has been proposed that changes in microbiota due to nonsteroidal anti-inflammatory drugs (NSAIDs) alter the composition of bile, and elevation of hydrophobic secondary bile acids contributes to small intestinal damage. However, little is known about the effect of NSAIDs on small intestinal bile acids, and whether bile alterations correlate with mucosal injury and dysbiosis. Here we determined the ileal bile acid metabolome and microbiota 24, 48 and 72 h after indomethacin treatment, and their correlation with each other and with tissue damage in rats. In parallel with the development of inflammation, indomethacin increased the ileal proportion of glycine and taurine conjugated bile acids, but not bile hydrophobicity. Firmicutes decreased with time, whereas Gammaproteobacteria increased first, but declined later and were partially replaced by Bilophila, Bacteroides and Fusobacterium. Mucosal injury correlated negatively with unconjugated bile acids and Gram-positive bacteria, and positively with taurine conjugates and some Gram-negative taxa. Strong positive correlation was found between Lactobacillaceae, Ruminococcaceae, Clostridiaceae and unconjugated bile acids. Indomethacin-induced dysbiosis was not likely due to direct antibacterial effects or alterations in luminal pH. Here we provide the first detailed characterization of indomethacin-induced time-dependent alterations in small intestinal bile acid composition, and their associations with mucosal injury and dysbiosis. Our results suggest that increased bile hydrophobicity is not likely to contribute to indomethacin-induced small intestinal damage.

Peri, pre and postnatal morphine exposure: exposure-induced effects and sex differences in the behavioural consequences in rat offspring.

This study investigated the behavioural consequences of peri, pre and postnatal morphine (MO) exposure in rats. From gestational day 1 dams were treated with either saline or MO subcutaneously once a day (5 mg/kg on the first 2 days, 10 mg/kg subsequently). Spontaneous locomotor activity in a new environment (habituation) and antinociceptive effects of MO were measured separately in male and female pups after weaning and also in late adolescence or adulthood. The rewarding effect of MO was assessed by conditioned place preference in adult animals. Both exposure-induced and sex differences were observed. A significant delay in habituation to a new environment and decreased sensitivity to the antinociceptive effect of MO were found in male offspring of MO-treated dams. In contrast, the place preference induced by MO was enhanced in the MO-exposed adult animals and this effect was more marked in females. Prenatal exposure to MO resulted in more marked changes than the postnatal exposure through maternal milk. The results indicate that a medium MO dose administered once-daily results in long-term consequences in offspring and may make them more vulnerable to MO abuse in adulthood.

Similarity and dissimilarity in antinociceptive effects of dipeptidyl-peptidase 4 inhibitors, Diprotin A and vildagliptin in rat inflammatory pain models following spinal administration.

Dipeptidyl-peptidase 4 (DPP4) enzyme is involved in the degradation of many biologically active peptides including opioids. Its role in pain transmission is poorly elucidated. Recently we reported on the spinal antihyperalgesic effects of DPP4 inhibitors, Ile-Pro-Ile (Diprotin A) and vildagliptin in carrageenan-evoked acute inflammatory pain in rats. The present study investigated the effects of intrathecal (it.) diprotin A and vildagliptin in Complete Freund's Adjuvant- (CFA) and formalin induced pain in rats. The former assay can model the subchronic inflammatory pain condition and the later one reflects both acute tonic and inflammatory pain conditions. The involvement of opioid receptor (OR) subtypes, Y1-, and GLP1 receptors were also investigated. In CFA pain model it. diprotin A or vildagliptin dose-dependently inhibits hyperalgesia in ipsilateral while has no effect in contralateral paws. The peak effect was achieved 30 min following drug administration which was used for further analysis. Both compounds showed naltrexone reversible antihyperalgesia. Co-administration of OR-subtype-selective antagonists with diprotin A and vildagliptin revealed involvement of µ and δ > µ opioid receptors, respectively. Co-administered Y1 but not GLP1 receptor antagonists reversed the antihyperalgesic action of both DPP4 inhibitors. In touch-hypersensitivity both compounds were ineffective. In formalin test only diprotin A showed µ and δ OR-mediated antinociception and only in the 2nd phase. This effect was Y1 or GLP-1 receptor antagonist insensitive. In conclusion, diprotin A and vildagliptin display antinociception of different mechanisms of action in subchronic inflammatory pain. Furthermore, the spinal pain relay points of inflammatory pain of acute or subchronic conditions were more effectively affected by diprotin A than vildagliptin which needs future elucidation.