Beneficial effect of metformin on tolerance to analgesic effects of sodium salicylate in male rats.

Background: Tolerance to the analgesic effects of opioids and non-steroidal anti-inflammatory drugs (NSAIDs) is a major concern for relieving pain. Thus, it is highly valuable to find new pharmacological strategies for prolonged therapeutic procedures. Biguanide-type drugs such as metformin (MET) are effective for neuroprotection and can be beneficial for addressing opioid tolerance in the treatment of chronic pain. It has been proposed that analgesic tolerance to NSAIDs is mediated by the endogenous opioid system. According to the cross-tolerance between NSAIDs, especially sodium salicylate (SS), and opiates, especially morphine, the objective of this study was to investigate whether MET administration can reduce tolerance to the anti-nociceptive effects of SS. Methods: Fifty-six male Wistar rats were used in this research (weight 200-250 g). For induction of tolerance, SS (300 mg/kg) was injected intraperitoneally for 7 days. During the examination period, animals received MET at doses of 50, 75, or 100 mg/kg for 7 days to evaluate the development of tolerance to the analgesic effect of SS. The hot plate test was used to evaluate the drugs' anti-nociceptive properties. Results: Salicylate injection significantly increased hot plate latency as compared to the control group, but the total analgesic effect of co-treatment with SS + Met50 was stronger than the SS group. Furthermore, the effect of this combination undergoes less analgesic tolerance over time. Conclusions: It can be concluded that MET can reduce the analgesic tolerance that is induced by repeated intraperitoneal injections of SS in Wister rats.

New phenols and one aminobenzoic acid derivative isolated from the roots of Rhus chinensis Mill.

Four new phenols and one new aminobenzoic acid derivative, with five known phenols were isolated from the roots of Rhus chinensis Mill. Their structures were elucidated by UV, IR, HRESIMS, 1D and 2D NMR spectra, as well as optical rotations. Compound 4 significantly inhibited mouse ear inflammation (inhibitory rate of 44.03%), and significantly extended the time of pain response (extension rate of 48.55%), showing significant anti-inflammatory and analgesic effects in vivo.

Pain modulation by oxytocin.

Oxytocin (OXT) was discovered in 1906 as a substance that promotes the pregnancy and childbirth. It affects uterine contraction and lactation. Furthermore, as one of its physiological properties, it exerts analgesic effects. The living body has an ascending pathway that transmits pain stimuli from the periphery to the center and a descending pathway that regulates the dorsal horn neurons from the upper center downward. OXT is involved in the pain-inhibitory descending pathway and generally assumed to exert analgesic effects. In this article, we describe the pain-suppressive effects of OXT, among its many physiological effects.

Analgesic and Psychotropic Effects of a New Bradykinin Antagonist.

A bradykinin B1 receptors antagonist PAV-0056, an 1,4-benzodiazepin-2-one derivative, intragastrically administrated to mice at doses of 0.1 and 1 mg/kg causes analgesia in the "formalin test" not inferior to that of diclofenac sodium (10 mg/kg) and tramadol (20 mg/kg). PAV-0056 at doses of 0.1 and 10 mg/kg has no anxiolytic and central muscle relaxant effects in mice and does not damage the gastric mucosa in rats. Based on the results of the conditioned place preference test, PAV-0056 also does not induce addiction in mice.

Ligustilide covalently binds to Cys703 in the pre-S1 helix of TRPA1, blocking the opening of channel and relieving pain in rats with acute soft tissue injury.

ETHNOPHARMACOLOGICAL RELEVANCE: The natural anodyne Ligustilide (Lig), derived from Angelica sinensis (Oliv.) Diels and Ligusticum chuanxiong Hort., has been traditionally employed for its analgesic properties in the treatment of dysmenorrhea and migraine, and rheumatoid arthritis pain. Despite the existing reports on the correlation between TRP channels and the analgesic effects of Lig, a comprehensive understanding of their underlying mechanisms of action remains elusive. AIM OF THE STUDY: The objective of this study is to elucidate the mechanism of action of Lig on the analgesic target TRPA1 channel. METHODS: The therapeutic effect of Lig was evaluated in a rat acute soft tissue injury model. The analgesic target was identified through competitive inhibition of TRP channel agonists at the animal level, followed by Fluo-4/Ca2+ imaging on live cells overexpressing TRP proteins. The potential target was verified through in-gel imaging, colocalization using a Lig-derived molecular probe, and a drug affinity response target stability assay. The binding site of Lig was identified through protein spectrometry and further analyzed using molecular docking, site-specific mutation, and multidisciplinary approaches. RESULTS: The administration of Lig effectively ameliorated pain and attenuated oxidative stress and inflammatory responses in rats with soft tissue injuries. Moreover, the analgesic effects of Lig were specifically attributed to TRPA1. Mechanistic studies have revealed that Lig directly activates TRPA1 by interacting with the linker domain in the pre-S1 region of TRPA1. Through metabolic transformation, 6,7-epoxyligustilide (EM-Lig) forms a covalent bond with Cys703 of TRPA1 at high concentrations and prolonged exposure time. This irreversible binding prevents endogenous electrophilic products from entering the cysteine active center of ligand-binding pocket of TRPA1, thereby inhibiting Ca2+ influx through the channel opening and ultimately relieving pain. CONCLUSIONS: Lig selectively modulates the TRPA1 channel in a bimodal manner via non-electrophilic/electrophilic metabolic conversion. The epoxidized metabolic intermediate EM-Lig exerts analgesic effects by irreversibly inhibiting the activation of TRPA1 on sensory neurons. These findings not only highlight the analgesic mechanism of Lig but also offer a novel nucleophilic attack site for the development of TRPA1 antagonists in the pre-S1 region.

Study on Analgesic Effects of Combined Thoracic Paravertebral Block Anesthesia or Erector Spinae Plane Block with Ultrasound Guided Transversus Abdominis Plane Block in Endoscopic Esophagectomy: A Clinical Anatomical Approach

SUMMARY: The application effect of transversus abdominis plane block (TAPB) combined with thoracic paravertebral block (TPVB) or erector spinae plane block (ESP) under ultrasound guidance in endoscopic radical resection of esophageal cancer under general anesthesia was studied. From March 2021 to February 2022, patients who underwent endoscopic radical resection of esophageal cancer in our hospital were selected as the research object, and 90 patients were selected as the samples. Patients were divided into groupA and group B according to the difference of blocking schemes. Group A received ESP and Group B received TPVB. The dosage of sufentanil, nerve block time, awakening time and extubation time of the two groups were counted. The postoperative pain, sedation effect, sleep satisfaction and analgesia satisfaction of the two groups were compared, and the complications of the two groups were observed. The nerve block time and extubation time in group A were shorter than those in group B (P0.05). At T2, T3 and T4, the visual analogue scale (VAS) scores of group A at rest and cough were significantly lower than those of group B (P0.05). The satisfaction of sleep and analgesia in group A was higher than that in group B (P0.05). The analgesic effect of ultrasound-guided TAPB combined with ESP is better than that of ultrasound-guided TAPB combined with TPVB, and it can shorten the time of nerve block and extubation, which is worth popularizing.

Se estudió el efecto de la aplicación del bloqueo del plano transverso del abdomen (TAPB) combinado con el bloqueo paravertebral torácico (TPVB) o el bloqueo del plano del erector de la columna (ESP) bajo guía ecográfica en la resección radical endoscópica del cáncer de esófago bajo anestesia general. Desde marzo de 2021 hasta febrero de 2022, en nuestro hospital, se seleccionaron como objeto de investigación pacientes sometidos a resección radical endoscópica de cáncer de esófago, y como muestra se seleccionaron 90 pacientes. Los pacientes se dividieron en el grupo A y el grupo B según la diferencia de esquemas de bloqueo. El grupo A recibió ESP y el grupo B recibió TPVB. Se contaron la dosis de sufentanilo, el tiempo de bloqueo nervioso, el tiempo de despertar y el tiempo de extubación de los dos grupos. Se compararon el dolor posoperatorio, el efecto de la sedación, la satisfacción del sueño y la satisfacción de la analgesia de los dos grupos y se observaron las complicaciones de los dos grupos. El tiempo de bloqueo nervioso y el tiempo de extubación en el grupo A fueron más cortos que los del grupo B (P0,05). En T2, T3 y T4, las puntuaciones de la escala visual analógica (EVA) del grupo A en repo- so y tos fueron significativamente más bajas que las del grupo B (P 0,05). La satisfacción del sueño y la analgesia en el grupo A fue mayor que en el grupo B (P0,05). El efecto analgésico de la TAPB guiada por ecografía combinada con ESP es mejor que el de la TAPB guiada por ecografía combinada con TPVB, y puede acortar el tiempo de bloqueo nervioso y extubación, lo que vale la pena popularizar.

Duration of the preemptive analgesic effects of low- and high-frequency transcutaneous electrical nerve stimulation in rats with acute inflammatory pain.

Transcutaneous electrical nerve stimulation (TENS) activates various pathways to induce antinociceptive effects, based on the frequencies used. This study evaluates the preemptive analgesic effects and their duration of low- (LT: 4 Hz) and high-frequency TENS (HT: 100 Hz) using a rat model of acute inflammatory pain. Acute inflammation was induced by injecting 1% formalin into the hind paws of rats. LT or HT was applied for 30 min before formalin injection. Pain-related behaviors, such as licking, flinching, and lifting, were recorded for 60 min postinjection. Immunohistochemistry was used to assess the number of phosphorylated extracellular signal-regulated kinase (pERK)- and c-fos-positive cells in the spinal cord. Naloxone, a µ-opioid receptors (MORs) antagonist, and naltrindole, a δ-opioid receptors (DORs) antagonist, were administered before TENS application. Pain behavior duration and pERK- and c-fos-positive cell expression were then measured. LT and HT pretreatment significantly reduced both pain behaviors and the number of pERK- and c-fos-positive cells postformalin injection. Naloxone and naltrindole partially reversed the effects of LT and HT, respectively. Notably, HT's analgesic effect lasted up to 120 min whereas that of LT persisted for 90 min. LT and HT effectively exerted their preemptive analgesic effects on acute inflammatory pain by inhibiting pERK and c-fos expression in the spinal cord. HT presented a longer-lasting effect compared to LT. MOR and DOR activation may contribute to LT and HT's analgesic mechanisms, respectively.

Phytochemical screening, antioxidant, immunomodulatory and analgesic potential of aqueous-ethanolic extracts of Euphorbia prostrata ait. and Crotalaria burhia Buch-Ham.

Euphorbia prostrata (E. prostrata) and Crotalaria burhia (C. burhia) are widely found in flora of the Cholistan Desert of Bahawalpur, Pakistan and are traditionally used to treat pain and chronic disease. The current study aimed to evaluate their phytochemical screening, antioxidant activity, in-vivo phagocytic activity, and analgesic activity. Both the plant extracts were investigated for phytochemical screening, Fourier Transform Infrared (FTIR) analysis, in-vitro antioxidant by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method, in-vivo immunomodulatory activity by macrophages phagocytosis using carbon clearance rate assay and analgesic activity by acetic acid produced writhing method. Phytochemical screening showed the presence of carbohydrates, saponins, tannins, phenols, quinines, proteins, terpenes, glycosides, and alkaloids. FTIR analysis revealed the existence of different functional groups in both extracts. The DPPH method showed that E. prostrata exhibited a high antioxidant potential with an IC50 of 62.5 µg/ml whereas C. burhia showed a lower antioxidant potential. At the dose of 200 mg/kg body weight (b. wt), both the extracts showed a significant increase in the phagocytic index by 5.2 ± 0.2, and, 4.8 ± 0.1 (p < 0.001) respectively which was close to the 100 mg/kg b. wt of the standard drug (Levamisole) 5.4 ± 0.2. Both the extracts at the dose of 200 mg/kg b. wt also significantly reduced the writhing (abdominal contractions) count by 13.7 ± 0.3 and, 25.3 ± 1.5 (p < 0.001), showing 71.8% and 47.6% of reduced analgesic activity compared to the standard drug dicloran (diclofenac sodium), respectively. In conclusion, extracts of both plants indicate their role in the management of various disorders to relieve pain and modulate the immune system.

Health Benefits of Electrolyzed Hydrogen Water: Antioxidant and Anti-Inflammatory Effects in Living Organisms.

Molecular hydrogen, the smallest and lightest molecule, serves as an intense reducing agent. Its distinct characteristics, including minimal size and neutral charge, enhance bioavailability and facilitate significant biological effects. Previously considered physiologically inert, hydrogen has gained recognition as a powerful therapeutic agent, known for its antioxidative and anti-inflammatory properties. Electrolyzed hydrogen water (EHW), enriched with molecular hydrogen, demonstrates remarkable antioxidative capabilities, indicating potential benefits for various diseases. Inflammation-induced reactive oxygen species (ROS) amplify inflammation, leading to secondary oxidative stress and creating a crosstalk between ROS and inflammatory responses. This crosstalk contributes to the pathogenesis and progression of chronic diseases. EHW interrupts this crosstalk, reducing inflammatory cytokines and oxidative stress across various disease models, suggesting therapeutic potential. EHW is also known for its anti-inflammatory effects, extending to pain management, as evidenced in models like sciatic nerve ligation and inflammatory pain. In an inflammatory bowel disease (IBD) model, EHW effectively alleviates abdominal pain, mitigating 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced inflammation and oxidative stress, offering insights for clinical applications. Additionally, hydrogen selectively targets harmful radicals, and EHW intake helps balance stress-induced hormonal dysregulation, potentially easing disorders associated with chronic stress.

Analgesic effect of the ultrasound-guided thoracolumbar paravertebral block in patients undergoing robot-assisted laparoscopic nephrectomy: a randomized controlled trial.

BACKGROUND: Paravertebral block has similar effect as epidural anesthesia, and has good somatic and visceral analgesic effect. Paravertebral block is widely used in thoracic surgery, but rarely used in abdominal surgery. AIMS: This study aimed to evaluate the analgesic effect of thoracolumbar paravertebral block in patients undergoing robot-assisted laparoscopic nephrectomy. METHODS: One hundred patients undergoing elective robot-assisted laparoscopic nephrectomy were included in this study. Based on whether the thoracolumbar paravertebral block was performed, the patients were randomly divided into the thoracolumbar paravertebral block combined with general anesthesia group (TL-PVB group) and simple general anesthesia group (NO-PVB group). Oxycodone was administered for patient-controlled intravenous analgesia (PCIA). The primary outcomes included the amount of remifentanil used during surgery, the amount of oxycodone used in 24 and 48 h after surgery. Secondary outcomes included the changes of heart rate (HR) and mean arterial pressure (MAP), time for the first analgesia administration, visual analog score (VAS) of pain during rest and movement, and time of postoperative recovery. RESULTS: Compared to the NO-PVB group, the amount of remifentanil used during surgery in patients with TL-PVB group was significantly reduced (1.78 ± 0.37 mg vs. 3.09 ± 0.48 mg, p < 0.001), the amount of oxycodone used 24 h after surgery was significantly reduced (8.70 ± 1.70 mg vs. 13.79 ± 2.74 mg, p < 0.001), and the amount of oxycodone used 48 h after surgery was remarkably reduced (21.83 ± 4.28 mg vs. 27.27 ± 4.76 mg, p < 0.001). There were significant differences in the changes of HR and MAP between the two groups (p < 0.001). The first analgesic requirement time of TL-PVB group was significantly longer than that of NO-PVB group (468.56 ± 169.60 min vs. 113.48 ± 37.26 min, p < 0.001). The postoperative VAS during rest and movement of TL-PVB group were significantly lower than that of NO-PVB group (p < 0.01). Compared with NO-PVB group, patients in TL-PVB group needed shorter time to awaken from anesthesia, leave the operating room, anal exhaust, get out of bed, and had shorter length of postoperative hospital stay (p < 0.001). The incidence of postoperative adverse reactions were lower in the TL-PVB group than that in the NO-PVB group (p < 0.05). CONCLUSIONS: Ultrasound-guided thoracolumbar paravertebral block significantly reduces intraoperative and postoperative opioid consumption, and provides better analgesia in patients undergoing robot-assisted laparoscopic nephrectomy, which is a recommendable combined anesthesia technique. TRIAL REGISTRATION: ChiCTR2200061326, 21/06/2022.

Comparison of the analgesic effect of dezocine and esketamine in combination with sufentanil respectively after laparoscopic cholecystectomy: a prospective randomized controlled study.

BACKGROUND: Sufentanil in combination with dezocine or esketamine is often used for postoperative analgesia. However, there is a lack of clinical evidence of efficacy. This study compares the analgesic effects of esketamine and dezocine combined with sufentanil for relieving pain after laparoscopic cholecystectomy(LC). METHODS: A total of 58 patients were randomly assigned to the esketamine group (ES group) and dezocine group (DE group). In the ES group, 1.5 mg/kg esketamine was used. In the DE group, 0.3 mg/kg dezocine was used. Primary outcome measures were Visual Analog Scale (VAS) score at 4 h, 8 h, 24 h and 48 h after surgery. The second outcome measures were Interleukin-6 (IL-6) and C-reactive protein (CRP) levels in the serum 10 minutes before anesthesia induction, and at 24 h and 48 h after surgery. RESULTS: The VAS scores at 4 h, 8 h, 24 h and 48 h after the surgery in the ES group vs DE group were 2.70 vs 3.50(P=0.013),2.35 vs 3.15(P=0.004),1.69 vs 2.58(P=0.002), and 1.50 vs 2.26(P=0.002), respectively. The serum IL-6 concentrations 10 minutes before anesthesia induction, and at 24 h and 48 h after surgery in the ES group and DE group were 34.39 and 34.12(P=0.901),112.33 and 129.60(P=0.014), and 89.69 and 108.46(P<0.001), respectively. The CRP levels in serum 10 minutes before anesthesia induction, and at 24 h and 48 h after the surgery in the ES group and DE group were 5.99 and 5.86(P=0.639), 28.80 and 35.37(P<0.001), and 23.17 and 30.11(P<0.001), respectively. CONCLUSION: For postoperative pain after LC, 1.5mg/kg esketamine provided better analgesia and reduced inflammation levels than 0.3mg/kg dezocine. TRIAL REGISTRATION: This trial was registered in the China Clinical Research Information Center in 31/05/2023 : https://www.chictr.org.cn/bin/home (Registration number: ChiCTR2300072011).

Comparison of analgesic effects between erector spinae and transversus abdominis plane blocks in patients undergoing laparoscopic cholecystectomy.

Objective: To compare the analgesic effects and incidence of postoperative adverse events after the erector spine plane (ESP) and transversus abdominis plane (TAP) blocks in patients undergoing laparoscopic cholecystectomy (LC). Methods: In this retrospective observational study, clinical data of 103 patients undergoing LC in Changxing County People's Hospital from October 2020 to October 2022 were retrospectively reviewed, and the patients were divided into ESP-group (n=56) and TAP-group (n=57) based on the block method. The operation time, the change of visual analogue scale (VAS) score of static (sVAS) and dynamic (dVAS) pain after operation, the patient-controlled dose, and the remedial analgesic dose at 24 hours after the operation were compared between the two groups. The occurrence of postoperative adverse reactions in both groups was recorded. Results: The dVAS scores of the ESP-group at one hour, three hours, six hours, and 12 hours after the operation were lower than those of the TAP-group (P<0.05). The patient-controlled dose and remedial analgesia dose of the ESP-group were significantly lower than those of the TAP-group (P<0.05). There was no difference in the incidence of postoperative nausea and vomiting between the two groups (P>0.05). Conclusions: ESP block and TAP block in LC patients have similar operation time and incidence of postoperative adverse events such as nausea and vomiting. However, short-term postoperative analgesic effect of ESP block is superior to TAP and requires a lower dose of analgesia.

Analgesic Effect of the Kampo Formula Yokukansan via the Suppression of Substance P in an Experimental Rat Model of Hunner-Type Interstitial Cystitis.

INTRODUCTION: Yokukansan (YKS), a Kampo formula used in traditional Japanese medicine, has an analgesic effect, and is used for various pain disorders. This study investigated its analgesic effects on Hunner-type interstitial cystitis (HIC) and its mechanism of action in animal models.   Methods: Rats with toll-like receptor-7 agonist (loxoribine)-induced HIC were used. Eight-week-old female Wistar rats were divided into three groups: control, HIC, and HIC-administered YKS (YKS + HIC). Bladder pain was assessed based on escape behavior using the von Frey test. Three days after HIC induction, the bladder and spinal cord were excised, and the expression of substance P (SP) was examined.   Results: The pain threshold decreased significantly in the HIC group compared to that in the control group, but this decrease was suppressed by further YKS administration. The expression of SP in the bladder wall and spinal cord increased significantly in the HIC group compared to that in the control group; however, this increase was suppressed by YKS administration. CONCLUSION: SP is involved in the onset of bladder pain via neurokinin 1 receptors in bladder tissue. YKS may be useful for managing HIC-induced pain, and the suppression of SP secretion is one of its mechanisms of action.

Can cannabidiol have an analgesic effect?

BACKGROUND: Cannabis, more commonly known as marijuana or hemp, has been used for centuries to treat various conditions. Cannabis contains two main components cannabidiol (CBD) and tetrahydrocannabinol (THC). CBD, unlike THC, is devoid of psychoactive effects and is well tolerated by the human body but has no direct effect on the receptors of the endocannabid system, despite the lack of action on the receptors of the endocannabid system. OBJECTIVES AND METHODS: We have prepared a literature review based on the latest available literature regarding the analgesic effects of CBD. CBD has a wide range of effects on the human body. In this study, we will present the potential mechanisms responsible for the analgesic effect of CBD. To the best of our knowledge, this is the first review to explore the analgesic mechanisms of CBD. RESULTS AND CONCLUSION: The analgesic effect of CBD is complex and still being researched. CBD models the perception of pain by acting on G protein-coupled receptors. Another group of receptors that CBD acts on are serotonergic receptors. The effect of CBD on an enzyme of potential importance in the production of inflammatory factors such as cyclooxygenases and lipoxygenases has also been confirmed. The presented potential mechanisms of CBD's analgesic effect are currently being extensively studied.

Enhancing Opiorphin's Metabolic Stability and Preserving its Potent Analgesic Effect: A Systematic Review.

BACKGROUND: Opiorphin has been reported to show a stronger analgesic effect than morphine without causing side effects brought about by morphine-like drugs. Functional opiorphin analogs have been created to enhance its metabolic stability and preserve its potent analgesic effect. OBJECTIVE: We conducted a systematic review to summarize all opiorphin analogs and identify those with the strongest metabolic stability and antinociceptive effect. METHODS: From a total of 122 articles, 11 made it to the quantitative synthesis phase. The included articles were categorized into the type of modifications used to improve the metabolic stability of the peptide, metabolism and toxicity profile, drug absorption and in vitro cytotoxicity, anti-nociceptive effect, the opiorphin analogs' administration in animals or humans, and the type of the test used to test the antinociceptive effect. RESULTS: The substitution of natural amino acid with a non-natural amino acid, side-chain modifications, or D-aminoacid substitution were the most used type of peptide modification to create opiorphin analogs. STR-324 and PEGylated liposomes loaded with opiorphin showed the best metabolism and toxicity performance. [C]-[(CH2)6]-QRF-[S-O-(CH2)8]-R showed high stability in human plasma and stronger inhibitory potency. YQRFSR and PEGylated liposomes loaded with opiorphin showed a stronger antinociceptive effect than the parent opiorphin or morphine, with an analgesic effect of PEGylated liposomes lasting more than 50%. Intravenous administration was the preferred method of opiorphin analog administration, and different tests were used to test the antinociceptive effect. CONCLUSION: This paper presents the first systematic review discussing opiorphin and opiorphin analogs and identifies the most promising candidates for future research.

Unraveling the parameters and biological mechanisms of CO2 laser therapy for acute pain relief.

Acute pain-related pathology is a significant challenge in clinical practice, and the limitations of traditional pain-relief drugs have made it necessary to explore alternative approaches. Photobiomodulation (PBM) therapy using CO2 laser has emerged as a promising option. In this study, we aimed to identify the optimal parameters of CO2 laser irradiation for acute pain relief through in vivo and in vitro experiments. First, we validated the laser intensity used in this study through bone marrow mesenchymal stem cells (BMSCs) experiments to ensure it will not adversely affect stem cell viability and morphology. Then we conducted a detailed evaluation of the duty cycle and frequency of CO2 laser by the hot plate and formalin test. Results showed a duty cycle of 3% and a frequency of 25 kHz produced the best outcomes. Additionally, we investigated the potential mechanisms underlying the effects of CO2 laser by immunohistochemical staining, and found evidence to suggest that the opioid receptor may be involved in its analgesic effect. In conclusion, this study provides insights into the optimal parameters and underlying mechanisms of CO2 laser therapy for effective pain relief, thereby paving the way for future clinical applications.

Analgesic effect of thoracic paravertebral block on patients undergoing thoracoscopic lobectomy under general anesthesia.

Objective: To investigate the analgesic effect of thoracic paravertebral block (TPVB) in patients undergoing thoracoscopic lobectomy under general anesthesia (GA). Methods: Clinical records of 82 patients who underwent thoracoscopic lobectomy under GA from October 2021 to October 2022 in the General Hospital of Southern Theater Command were retrospectively analyzed. The patients were divided into two groups according to the method of anesthesia used: general anesthesia group (Group-G, n=37), and TPVB plus GA group (Group-T, n=45). The analgesic effect, mean arterial pressure (MAP), heart rate (HR) and the rate of adverse events in both groups were compared. Results: Visual analogue scale (VAS) scores of patients in Group-T at 12h, 24h and 48h after the operation were significantly lower compared to Group-G (P<0.05). MAP and HR the time of tracheal intubation induction (T1), single lung ventilation (T2), skin incision (T3), operation completion (T4), and 20 minutes after the extubation (T5) were lower in both groups compared to T0, and were significantly higher in Group-T compared to Group-G (P<0.05). The rate of adverse events in Group-T was 6.67%, significantly lower compared to Group-G (24.32%) (P<0.05). Conclusions: TPVB combined with GA can improve the analgesic effect, improve MAP and HR during the operation, and reduce the incidence of adverse events in patients undergoing thoracoscopic lobectomy.

Comparison of the Analgesic Effects of Low-Dose Ketamine Versus Fentanyl in Patients With Long Bone Fractures in the Emergency Department: A Prospective Observational Study.

Aim and background In most emergency departments (ED), opioids are the primary analgesic agents for trauma patients. However, safe alternative drugs are required because of possible adverse effects. Ketamine, an anesthetic agent, provides satisfactory analgesia at low doses and is an alternative drug that has begun to be used in numerous areas with fewer side effects. This study aimed to compare low-dose ketamine and fentanyl infusions in terms of their pain-relieving effects and observed adverse effects in patients presenting to the ED with isolated long bone fractures. Materials and methods This single-center observational study was conducted in the ED of the Marmara University Pendik Training and Research Hospital between August 2018 and December 2019. Patients diagnosed with isolated long bone fractures who were administered low-dose ketamine or fentanyl rapid infusions for pain relief were included in the study. Patient pain scores were evaluated using the visual analog scale (VAS) with a standard horizontal 10-centimeter line. The primary outcome of the study was to compare the changes in pain at 30 and 60 min after medication administration for each group. Results A total of 100 patients were included in the study. Ketamine infusion was administered to 48% (n=48) of the patients as a pain reliever. After 60 min of observation, pain was significantly reduced in both study groups. However, the pain scores at baseline (p=0.319), 30 min (p=0.631), and 60 min (p=0.347) after treatment were similar in both groups. In terms of the observed adverse effects, dizziness was more common in the ketamine group (p=0.010). Conclusion The results of this study showed that low-dose ketamine infusion (0.3 mg/kg/h) had a similar effect to fentanyl infusion (1 mcg/kg/h) as a pain reliever in patients with isolated long bone fractures in the ED.

Current status of GABA receptor subtypes in analgesia.

Gamma-aminobutyric acid (GABA), a non-protein-producing amino acid synthesized from the excitatory amino acid glutamate via the enzyme glutamic acid decarboxylase, is extensively found in microorganisms, plants and vertebrates, and is abundantly expressed in the spinal cord and brain. It is the major inhibitory neurotransmitter in the mammalian nervous system. GABA plays crucial roles in the regulation of synaptic transmission, the promotion of neuronal development and relaxation, and the prevention of insomnia and depression. As the major inhibitory neurotransmitter, GABA plays pivotal roles in the regulation of pain sensation, which is initiated by the activation of peripheral nociceptors and transmitted to the spinal cord and brain along nerves. GABA exerts these roles by directly acting on three types of receptors: ionotropic GABAA and GABAC receptors and G protein-coupled GABAB receptor. The chloride-permeable ion channel receptors GABAA and GABAC mediate fast neurotransmission, while the metabotropic GABAB receptor mediates slow effect. Different GABA receptors regulate pain sensation via different signaling pathways. Here we highlight recent updates on the involvement of specific GABA receptors and their subtypes in the process of pain sensation. Further understanding of different GABA receptors and signaling pathways in pain sensation will benefit the development of novel analgesics for pain management by targeting specific GABA receptor subtypes and signaling pathways.

What is the analgesic range of acupuncture stimulus for treating acute pain?

Introduction: Since the analgesic effect of acupuncture stimulation is derived from different mechanisms depending on the type of pain, it is important to know which acupuncture points to stimulate. In this study, to confirm the effect of acupuncture stimulation on acute pain from a neurological point of view, somatosensory evoked potential and sensory threshold changes were evaluated to identify the nerve range that is affected by acupuncture stimulation on LI4 (Hapgok acupuncture point, of the radial nerve) during acute pain. Methods: The subjects were 40 healthy men and women aged 19-35 years. The study was designed as a randomly controlled, crossover trial with acupuncture stimulation at LI4 as the intervention. The washout period for acupuncture stimulation was 2 weeks, and the subjects were divided into two groups, i.e., an acupuncture stimulation group and a nonstimulation group, with 10 men and 10 women in each group. Somatosensory evoked potential measurement was carried out for 5 min by alternately applying 2 HZ-pulse electrical stimulation to the thumb and the little finger of the hand acupunctured with a 64-channel electroencephalogram. The verbal rating scale was used before and after each acupuncture stimulation session. Result and discussion: The results of the study confirmed that the somatosensory evoked potential amplitude value of the thumb was significantly decreased and that the intensity of sensory stimulation corresponding to a verbal rating scale score of 6 was significantly increased only in the thumb after acupuncture stimulation. Therefore, the results show that acupuncture treatment for acute pain is more effective when direct acupuncture stimulation is applied to the painful area.