Mechanisms of Nausea and Vomiting: Current Knowledge and Recent Advances in Intracellular Emetic Signaling Systems

Olanzapine for the Prevention of Postoperative Nausea and Vomiting: An Updated Meta-Analysis With Trial Sequential Analysis

BACKGROUND AND OBJECTIVES

Postoperative nausea and vomiting (PONV) notably affects up to 30% of surgical patients, resulting in elevated medical service costs, dehydration, discomfort, and delayed recovery. Although standard antiemetic medications are effective, but they may not completely prevent PONV due to complicated underlying pathophysiology involving various neurotransmitter systems. Therefore, this systematic review and meta-analysis evaluates the efficacy and safety of olanzapine, an atypical antipsychotic with wide-spectrum receptor antagonism, in PONV reduction.

METHODS

A comprehensive literature search was conducted to retrieve randomized controlled trials (RCTs) comparing prophylactic olanzapine to other traditional antiemetics or placebo in multiple electronic databases, including PubMed, Scopus, Cochrane Library, and Web of Science. However, the main outcome was the incidence rate of PONV within 24 hours postsurgical operations. Furthermore, risk differences (RD) and relative risks (RR) were calculated on Review Manager (RevMan), and trial sequential analysis (TSA) was established to precisely assess the evidence reliability of olanzapine.

RESULTS

Five RCTs with 793 patients were eligible for our inclusion criteria. Olanzapine potentially decreased PONV risk (RR = 0.67; 95% CI, 0.56, 0.80) and absolute risk reduction by 15% (RD = -0.15; 95% CI, -0.24, -0.06). Furthermore, subgroup analysis by dose revealed that the 10 mg dose of olanzapine had a strong effect in lowering PONV. However, only the 5 mg dose showed a statistically significant reduction in the use of rescue antiemetics (RR = 0.28; 95% CI, 0.10, 0.84). Moreover, TSA demonstrated and confirmed notable evidence supporting the efficacy of olanzapine.

CONCLUSION

Olanzapine potentially decreases PONV incidence rates, particularly when combined with traditional antiemetics, indicating its pivotal role in PONV prevention. There is a pressing need for further research to optimize dosing and assess its efficacy among different surgical populations and procedures.

Serotonin Receptors Polymorphisms Are Associated With Cyclic Vomiting Syndrome

BACKGROUND

Cyclic vomiting syndrome (CVS) is a disorder characterized by sudden, recurrent episodes of severe nausea and vomiting. The pathophysiology of CVS is not known but genetic factors that regulate emetic neurocircuitry have been proposed. The aim of this study was to investigate whether different variations in genes encoding serotonin receptors (HTRs) are associated with susceptibility to CVS and/or CVS symptoms.

METHODS

This case-control study included 70 patients with CVS:16 male and 54 female, and 2504 healthy controls from the 1000 Genomes Project database. Single-nucleotide polymorphisms (SNPs) in genes encoding serotonin receptors (HTR1B, HTR1D, HTR3B and HTR3C) and correlations between SNPs and the symptoms of CVS were determined.

KEY RESULTS

Our study discovered that patients with GG, AA and GG genotypes of HTR1B/D rs6296, rs6298 and rs6300, respectively, as well as the CC genotype of HTR3B rs176744 are associated with an increased risk (p < 0.001), whereas allele C in rs3788987 (HTR3B, p < 0.01) and allele A in rs6766410 (HTR3C, p < 0.05) were associated with a decreased risk of CVS. In addition, statistical analysis indicated that CVS patients with GA or AA genotypes of HTR1D rs676643 gene have a seven-fold increase in risk of depression compared to patients with GG genotype (p < 0.01).

CONCLUSIONS AND INFERENCES

Our study revealed for the first time that variations in 5-HTR genes may contribute to CVS susceptibility and CVS-related symptoms.

An application of deep learning model InceptionTime to predict nausea, vomiting, diarrhoea, and constipation using the gastro-intestinal pacemaker activity drug database (GIPADD)

The accurate preclinical prediction of adverse drug reactions (ADRs), such as nausea and vomiting, remains a challenge. The Gastro-Intestinal Pacemaker Activity Drug Database (GIPADD) ( http://www.gutrhythm.com/public_database ) is a new source of electrophysiological big data for drug research. Over the past 2 years, the database has doubled in size, and now contains the electrophysiological profiles of 172 drugs across 11,943 datasets. This study used a state-of-the-art deep-learning model with time-series classification to explore the feasibility of using raw electrophysiological recordings from tissues to predict ADRs. The GIPADD contains the recordings of the electrical activity of various gastrointestinal tissues (stomach, duodenum, ileum, and colon) exposed to a drug at three or more different concentrations, representing the effects of the drug on gastrointestinal pacemaker activity. Each drug in the database is associated with at least 60 recordings. The datasets are divided in a ratio of 8:2 for training and validation. A modified InceptionTime classifier (ICT) was used to predict whether a drug induces ADRs, using data from the SIDER database as the target. Concentrations and tissues were added as covariates and added to the input of the model during forward propagation. We also established a negative control with shuffled target labels, and external validation was conducted using time-shifted recording predictions. The best model for predicting nausea, vomiting, diarrhoea, and constipation achieved by-drug accuracies of 0.87, 0.89, 0.85, and 0.91, respectively; by-drug precision (class 1) of 0.88, 0.90, 0.99, and 0.89, respectively; and area under the receiver operating characteristic curve (AUROC) values of 0.84, 0.87, 0.94, and 0.96, respectively. The best model was an ensemble of five independent ICT classifiers trained on the same dataset. Models trained using shuffled labels (negative controls) exhibited significantly lower accuracy, precision, and AUROC values than models trained using correctly labelled datasets, indicating that ICT classifiers successfully identified latent features in the raw recordings associated with ADRs. The combined benefits of the GIPADD and deep learning may accelerate drug safety testing and drug development by enabling the reliable analysis of electrophysiological drug profiles during the preclinical stage.

Pyridoxine Prevents Postoperative Nausea and Vomiting in Gynecologic Laparoscopic Surgery: A Double-blind Randomized Controlled Trial

BACKGROUND

Postoperative nausea and vomiting are common complications after gynecologic laparoscopic surgery. Pyridoxine has been recommended as a first-line drug to prevent and treat nausea and vomiting during pregnancy; however, its efficacy in preventing postoperative nausea and vomiting remains unclear.

METHODS

Patients of 18 to 65 yr old who received elective gynecologic laparoscopic surgery under general anesthesia were randomized into either the pyridoxine group or the control group. The pyridoxine group received 0.2 g of vitamin B 6 before anesthesia induction, and the control group received normal saline intravenously. Both groups received a similar regimen of combined intravenous and inhalation general anesthesia. All patients received dexamethasone (intravenous) after anesthesia induction and ondansetron (intravenous) before surgery completion. Postoperative nausea and vomiting occurrence was recorded according to the patients' self-reported data. Other clinical data were collected from hospital system, and concentrations of blood interleukin-6 and substance P were measured by enzyme-linked immunosorbent assay.

RESULTS

A total of 442 patients were screened, and 240 patients were equally randomized to the pyridoxine or control group. The incidence of postoperative nausea and vomiting was statistically significant lower in the pyridoxine group than in the control group (16.7% [20 of 120] vs . 35.8% [43 of 120]; relative risk = 0.47 [95% CI, 0.29 to 0.74]; absolute risk reduction = 0.20 [95% CI, 0.08 to 0.30]; P = 0.001), and pyridoxine decreased the incidence of postoperative nausea (12.5% [15 of 120] vs . 35% [42 of 120]; relative risk = 0.36 [95% CI, 0.21 to 0.61]; absolute risk reduction = 0.23 [95% CI, 0.12 to 0.33]; P < 0.001). There were no statistical differences in postoperative vomiting, time to the first postoperative nausea and vomiting occurrence, pain, serum interleukin-6 and substance P, and leukocyte and neutrophil counts.

CONCLUSIONS

In this single-center randomized trial, pyridoxine plus dexamethasone and ondansetron reduced the incidence of postoperative nausea and vomiting in patients undergoing elective gynecologic laparoscopic surgery under general anesthesia. These findings need to be validated in multicenter studies in diverse populations to ensure generalizability.

Electrical stimulation of the dorsolateral prefrontal cortex inhibits vestibular signalling in humans: A BOLD fMRI study

BACKGROUND

Low-frequency sinusoidal galvanic vestibular stimulation (sGVS) can induce perceptions of sway and nausea through entraining vestibular afferent firing to the sinusoidal stimulus. As recently shown, concurrent dorsolateral prefrontal cortex (dlPFC) stimulation via transcranial alternating current stimulation (tACS) greatly attenuates these vestibular perceptions.

OBJECTIVE

Given that both vestibular afferents and dlPFC efferents project to the insular cortex, it was reasoned that the insula is the most likely area for the top-down inhibitory interaction to take place.

METHODS

To identify the sites of this interaction, blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was collected whilst simultaneously delivering sinusoidal electrical stimulation (±2 mA, 0.2 Hz, 60 cycles) to 20 participants. These stimuli were randomly applied as follows: (i) bilateral sGVS alone via the mastoid processes; (ii) tACS of the dlPFC alone at electroencephalogram site F4; and (iii) sGVS and tACS together.

RESULTS

Altered BOLD signal-intensity patterns were identified in the parieto-insular vestibular cortex and thalamus when comparing both sGVS and dlPFC stimulation to concurrent stimulation. Within the brainstem, signal-intensity increased in the inferior olivary nucleus and decreased in the nucleus of the solitary tract during concurrent stimulation, when analysed relative to single stimuli. Because concurrent stimulation elicited different activation patterns in each of these regions compared to the single stimuli, they were considered to be key for the interaction.

CONCLUSION

Given the role each plays in dlPFC and vestibular pathways, the inhibitory function exerted by the dlPFC on vestibular processing likely involves ongoing modulation of one or several of these cortical or subcortical areas.

Effect of non-pharmacological interventions on chemotherapy induced delayed nausea and vomiting for tumors: A systematic review and Bayesian network meta-analysis

OBJECTIVE

To evaluate the efficacy of non-pharmacological interventions in improving chemotherapy induced delayed nausea and vomiting symptoms using a network meta-analysis.

METHODS

Four Chinese databases (CNKI, Wanfang Data Knowledge Service Platform, VIP, Sinomed) and five English databases (PubMed, Cochrane Library, Embase, Web of Science, CINAHL) were searched from the establishment of the database to April 2024. A Bayesian network meta-analysis was performed on the response rate to the improvement of chemotherapy induced delayed nausea and vomiting, as well as improvement in KPS score, under different non-pharmacological interventions by using R 4.4.0 software and the GeMTC package.

RESULTS

A total of 58 RCTs 4081 patients were selected, involving 14 non-pharmacological interventions. The results of Meta-analysis showed that acupoint patch was identified as the most probable superior intervention in the improvement of chemotherapy induced delayed nausea and vomiting, and acupuncture was identified as the most probable superior intervention on the improvement of KPS scores.

CONCLUSION

Non-pharmacological interventions can serve as an effective complementary approach to managing delayed chemotherapy-induced nausea and vomiting. In particular, acupoint application may be the optimal complementary therapy to mitigate the incidence of delayed nausea and vomiting, though more high-quality, large-scale evidence is required to conclusively demonstrate the efficacy of acupuncture in enhancing the quality of life for cancer patients.

Synergistic Antiemetic Effects of Nerolidol on Domperidone, Hyoscine, and Ondansetron: In Vivo and in Silico Investigations on Receptor Binding Affinity

The present study was designed to measure the potential antiemetic properties of nerolidol (NDL) via in vivo and in silico studies. To induce emesis copper sulfate pentahydrate (CuSO4.5H2O) was administered at a dose of 50 mg/kg (orally) to 2-day-old chicks. The test sample (NDL) was given at two doses of 50 and 100 mg/kg. b.w. orally. Additionally, aprepitant (16 mg/kg), domperidone (6 mg/kg), hyoscine (21 mg/kg), ondansetron (5 mg/kg), and diphenhydramine (10 mg/kg) were given also orally as positive controls. To observe the modulatory effects of the test sample, combination therapies with reference drugs were also administered to three different groups of animals. Molecular docking and visualization of ligand-receptor interaction were performed against several emesis-inducing receptors (5HT3, D2, D3, H1, and M1-M5) using diverse computational tools. Pharmacokinetics and drug-likeness of the selected ligands were also calculated. Findings demonstrated that NDL significantly (p <0.05) dose-dependently lessens the mean number of retches and delays the emetic onset in the chicks. The combined drug therapy with ondansetron exposed better antiemetic activity. In addition, in silico analysis, NDL has greater binding affinity (-7.3 kcal/mol) against M2 and M3 receptors. In conclusion, NDL exerted mild antiemetic activity with synergistic properties through muscarinic receptors.

Endocannabinoid signaling in stress, nausea, and vomiting

BACKGROUND

Classical antiemetics that target the serotonin system may not be effective in treating certain nausea and vomiting conditions like cyclic vomiting syndrome (CVS) and cannabinoid hyperemesis syndrome (CHS). As a result, there is a need for better therapies to manage the symptoms of these disorders, including nausea, vomiting, and anxiety. Cannabis is often used for its purported antiemetic and anxiolytic effects, given regulation of these processes by the endocannabinoid system (ECS). However, there is considerable evidence that cannabinoids can also produce nausea and vomiting and increase anxiety in certain instances, especially at higher doses. This paradoxical effect of cannabinoids on nausea, vomiting, and anxiety may be due to the dysregulation of the ECS, altering how it maintains these processes and contributing to the pathophysiology of CVS or CHS.

PURPOSE

The purpose of this review is to highlight the involvement of the ECS in the regulation of stress, nausea, and vomiting. We discuss how prolonged cannabis use, such as in the case of CHS or heightened stress, can dysregulate the ECS and affect its modulation of these functions. The review also examines the evidence for the roles of ECS and stress systems' dysfunction in CVS and CHS to better understand the underlying mechanisms of these conditions.

Comprehensive Analysis of Strong Opioid Side Effects in Palliative Care Using the SIDER Database

Background/Objectives: There exist multiple opioid-based treatments in palliative care, each with distinct side effect profiles. When adverse events occur, switching opioids can help maintain effective pain management. However, owing to limited clinical evidence, no comprehensive guidelines exist for opioid switching. This study employed the Side Effect Resource (SIDER) database, which aggregates adverse event data from clinical trials and package inserts, to analyze the side effects of five commonly used "strong opioids" in palliative care in Japan, namely morphine, fentanyl, oxycodone, hydromorphone, and tapentadol. Methods: Data on the names and incidence of adverse events for each opioid were extracted from SIDER 4.1, developed by the Max Delbrück Center for Molecular Medicine. Cluster analysis and principal component analysis were performed to interpret the data. Results: The key side effects of opioids were nausea, vomiting, constipation, and drowsiness. Fentanyl was more frequently associated with nausea and vomiting but less frequently with constipation and drowsiness. Tapentadol caused nausea relatively more frequently and constipation less frequently. Oxycodone was prominently linked to drowsiness, whereas morphine was frequently associated with constipation and drowsiness. Hydromorphone was associated with higher rates of constipation and vomiting but lower incidences of nausea and drowsiness. Conclusions: All side effects characterizing the opioids were related to μ-opioid receptor stimulation, although the present study findings highlight differences in the frequency of specific side effects among the opioids. These results provide objective insights that can guide opioid switching in response to adverse effects.

Nursing Supports for Managing Nausea and Vomiting in Patients with Cancer Having a Prognosis of Months or Weeks: A Multisite Cross-Sectional Study of Palliative Care Nurses in Japan

Purpose

This study aimed to clarify the types of nursing support provided by palliative care unit (PCU) nurses in Japan to manage nausea and vomiting in patients with cancer who have a prognosis of months or weeks.

Methods

This multisite cross-sectional study surveyed registered nurses from all 389 PCUs across Japan. Eligible participants were nurses providing direct care to patients. Data were collected via online surveys from October 2023 to March 2024. The frequency of 13 types of nursing supports for nausea and vomiting was evaluated using a five-point Likert scale, stratified by patient prognosis (months or weeks).

Results

Of the 389 PCUs invited, 162 (41.6%) consented to participate. A total of 2448 nurses were invited, of which 539 (22.3%) responded. The most frequently implemented nursing supports were "avoiding unpleasant odors," "providing shaved ice or ice chips," "providing fresh air," and "gargling with cold water." These were consistently practiced by many nurses, regardless of patient prognosis. Conversely, specialized supports such as "reiki," "acupressure," "guided relaxation exercises," "therapeutic touch," and "foot reflexology" were rarely or seldom used.

Conclusion

Noninvasive, simple nursing supports that do not require specialized knowledge or skills were frequently provided to patients with cancer who were experiencing nausea and vomiting, irrespective of their prognosis. However, nursing supports that require specialized knowledge and skills were rarely used. Further research is needed to evaluate the effectiveness of these nursing supports.

Disruption of serotonin homeostasis in intestinal organoids provides insights into drug-induced gastrointestinal toxicity

Drug-induced gastrointestinal toxicity is a frequent clinical adverse event that needs to be carefully monitored and managed to ensure patient compliance. While preclinical assessment of drug-induced gastrointestinal toxicity mostly relies on animal experimentation, intestinal organoids have gained increasing attention to identify gastrointestinal toxicants in vitro. Nonetheless, current in vitro protocols primarily assess structural alterations induced by drugs, whereas gastrointestinal adverse events can often stem from functional disturbances. Disruption of serotonin signaling in the gastrointestinal tract is associated with impaired motility, as well as nausea and vomiting. We aimed to investigate alterations of serotonin homeostasis in organoids derived from the canine small intestine as a driver of drug-induced gastrointestinal toxicity. Treatment of the organoids with a compound (NVS-1) inducing acute gastrointestinal toxicity in dogs as well as with three tyrosine kinase inhibitors with known preclinical and clinical gastrointestinal adverse effects (afatinib, crizotinib and vandetanib) led to increased supernatant serotonin levels. Mechanistic assays showed that, while NVS-1 and afatinib stimulate serotonin release, crizotinib and vandetanib inhibit serotonin re-uptake via direct inhibition of the serotonin re-uptake transporter. Using a data mining approach, we further suggest that inhibition of serotonin re-uptake could contribute to gastrointestinal toxicity observed with multiple marketed drugs. In conclusion, we present the implementation of a novel in vitro gastrointestinal toxicity endpoint that could complement current methods and serve as a mechanistic and predictive/screening tool for drug-induced gastrointestinal toxicity.

A Prediction Model for Postoperative Nausea and Vomiting After Laparoscopic Surgery for Gynecologic Cancers

BACKGROUND

Postoperative nausea and vomiting (PONV) is among the most common adverse events, accompanied with impaired prognosis. This study aimed to investigate independent predictors for PONV after laparoscopic surgery for gynecologic cancers and identify a nomogram model.

METHODS

Elderly patients who underwent laparoscopic surgery for gynecologic cancers between 2021 and 2024 were retrospectively enrolled. The primary observational endpoint was set as the occurrence of PONV within 72 h after surgery. Independent risk factors associated with PONV were identified by binary logistic regression, and further incorporated into the nomogram prediction mode by R.

RESULTS

Of 337 enrolled patients, 104 experienced PONV with an overall incidence of 30.9%. Multivariate logistic regression analysis indicated body mass index (BMI) ≥ 24.0 (OR: 2.67, 95% CI: 1.37-5.23, P = 0.004), Afpel score (OR: 6.54, 95% CI: 3.52-12.15, P < 0.001), anxiety (OR: 3.14, 95% CI: 1.16-8.50, P = 0.025), 5-hydroxytryptamine (5-HT) (OR: 1.05, 95% CI: 1.02-1.07, P < 0.001), prostaglandin E2 (PGE2) (OR: 1.05, 95% CI: 1.01-1.08, P = 0.007), and albumin/fibrinogen ratio (AFR) (OR: 0.40, 95% CI: 0.28-0.56, P < 0.001) were six independent risk factors for PONV. The nomogram model based on these factors has good predictive value for PONV, with an AUC of 0.898.

CONCLUSIONS

This study identified an individual nomogram prediction model to visually represent the regression model for predicting PONV after laparoscopic surgery for gynecologic cancers.

6-Shogaol attenuates cisplatin induced emesis by inhibiting the mtDNA-cGAS-STING signaling pathway in a rat pica model

ETHNOPHARMACOLOGICAL RELEVANCE

Ginger (Zingiber officinale Rosc.) is a traditional anti-emetic herb. 6-shogaol, the main active compound of ginger, is reported to possess a variety of bioactivities.

AIMS OF THE STUDY

This study aimed to investigate the anti-emetic effect of 6-shogaol in a cisplatin-induced pica rat model and explore its underlying mechanism.

MATERIALS AND METHODS

The rat pica model was established by intraperitoneal injection of cisplatin. The pathological damage of gastric antrum and ileum were observed by hematoxylin-eosin staining. The levels of serum 8-Hydroxy-desoxyguanosine (8-OHdG) were detected by ELISA. The expression of ZO1 tight junction protein (TJP-1) and occludin in ileum were determined by IHC. The levels of 8-oxo G DNA glycosylase 1 (OGG1), flap endonuclease 1 (FEN1), cyclic GMP-AMP synthase (cGAS), stimulator of interferon genes (STING), phospho-STING (p-STING), TANK binding kinase 1 (TBK1), phospho-TBK1 (pTBK1), nuclear factor kappa-B (NF-κB) and phospho-NF-κB (p-NF-κB) in gastric antrum and ileum were assayed by western blotting.

RESULTS

We found that 6-shogaol significantly improved pica behavior in rats by downregulating NF-κB and IL-1β level, and ameliorating inflammatory damage in gastric antrum and ileum. Mechanistically, cGAS-STING axis activated by mtDNA is responsible for the cisplatin-induced gastrointestinal inflammatory responses. 6-Shogaol inhibited the mtDNA-cGAS-STING signaling pathway by increasing the level of base-excision repair enzyme OGG1 and decreasing the level of endonuclease FEN1.

CONCLUSIONS

This study indicates that 6-shogaol has a therapeutic effect against chemotherapy-induced nausea and vomiting (CINV), potentially attributable to the suppression of the mtDNA-cGAS-STING signaling pathway.

GLP-1 and the Neurobiology of Eating Control: Recent Advances

Obesity is now considered a chronic relapsing progressive disease, associated with increased all-cause mortality that scales with body weight, affecting more than 1 billion people worldwide. Excess body fat is strongly associated with excess energy intake, and most successful anti-obesity medications (AOMs) counter this positive energy balance through the suppression of eating to drive weight loss. Historically, AOMs have been characterized by modest weight loss and side effects which are compliance-limiting, and in some cases life-threatening. However, the field of obesity pharmacotherapy has now entered a new era of AOMs based on analogues of the gut hormone and neuropeptide glucagon-like peptide-1 (GLP-1). The latest versions of these drugs elicit unprecedented levels of weight loss in clinical trials, which are now starting to be substantiated in real-world usage. Notably, these drugs reduce weight primarily by reducing energy intake, via activation of the GLP-1 receptor on multiple sites of action primarily in the central nervous system, although the most relevant sites of action, and the neural circuits recruited remain contentious. Here we provide a targeted synthesis of recent developments in the field of GLP-1 neurobiology, highlighting studies which have advanced our understanding of how GLP-1 signaling modulates eating, and identify open questions and future challenges we believe still need to be addressed to aid the prevention and/or treatment of obesity.

Neuron-Derived Extracellular Vesicles miRNA Profiles Identify Children Who Experience Adverse Events after Ketamine Administration for Procedural Sedation

Ketamine provides the highest safety profile among sedatives for procedural sedation and analgesia in the pediatric emergency setting. However, it can cause vomiting and recovery agitation. No studies have examined epigenetic factors, such as microRNAs, for predicting the occurrence of these adverse events. Neuronal-derived extracellular vesicle microRNA profiles were studied to predict the occurrence of ketamine-induced vomiting and recovery agitation in children. For this aim, a single-center prospective pharmacoepigenetic study was performed and 50 children who underwent procedural sedation with intravenous ketamine as the only sedative drug were enrolled between October 2019 and November 2022. MiRNA profiling in plasma neural-derived extracellular vesicles was analyzed through next-generation sequencing and measured before treatment with ketamine. Twenty-two patients experienced vomiting or recovery agitation. Among the 16 differentially expressed microRNAs, the upregulated miR-15a-5p and miR-484 targeted genes related to N-methyl-D-aspartate (NMDA) receptor activity, including glutamate ionotropic receptor NMDA type subunit 2A (GRIN2A). Preliminary data confirmed lower GRIN2A levels in patients who developed these events. Downregulated miR-126-3p and miR-24-3p targeted AMPA receptor-associated genes. Functional analyses of gene targets revealed the enrichment of glutamatergic and neurotrophins signaling. Recovery agitation was associated with this network. Vomiting was related to dopaminergic and cholinergic systems. Three miRNAs (miR-18a-3p, miR-484, and miR-548az-5p) were identified as predictive biomarkers (AUC 0.814; 95% CI: 0.632-0.956) for ketamine-induced vomiting and recovery agitation. MicroRNA profiles can predict the development of ketamine-induced vomiting or recovery agitation in children. This study contributes to the understanding of the mechanisms underlying ketamine-induced adverse events.

Approach to Meal-Related Nausea and Vomiting

Nausea and vomiting are common symptoms that frequently lead to evaluation in the outpatient and inpatient settings. The pathophysiology of nausea and vomiting is complex, and the list of potential etiologies is vast. Patients with nausea and vomiting frequently report that eating exacerbates symptoms. Noteworthy gastrointestinal causes for meal-related nausea and vomiting include gastroparesis, functional dyspepsia, dumping syndrome, superior mesenteric artery syndrome, and median arcuate ligament syndrome. A number of carefully selected diagnostic tests, utilization of the Rome criteria, and an appreciation for the epidemiology of these various conditions can help the clinician hone in on the underlying cause. Importantly, a properly performed and interpreted gastric emptying study is essential to making an accurate diagnosis of gastroparesis and distinguishing this condition from functional dyspepsia, a common disorder of gut-brain interaction. There are a number of treatment options for nausea and vomiting, and the treatment approach is dependent on the specific cause for the meal-related symptoms. This article examines the approach to meal-related nausea and vomiting by reviewing tests to consider in the diagnostic evaluation of symptoms, followed by a discussion of clinically relevant disorders and disorder-specific treatments.

The Role of Cannabinoids and the Endocannabinoid System in the Treatment and Regulation of Nausea and Vomiting

Despite using the recommended anti-emetic treatments, control of nausea and vomiting is still an unmet need for cancer patients undergoing chemotherapy treatment. Few properly controlled clinical trials have evaluated the potential of exogenously administered cannabinoids or manipulations of the endogenous cannabinoid (eCB) system to treat nausea and vomiting. In this chapter, we explore the pre-clinical and human clinical trial evidence for the potential of exogenous cannabinoids and manipulations of the eCB system to reduce nausea and vomiting. Although there are limited high-quality human clinical trials, pre-clinical evidence suggests that cannabinoids and manipulations of the eCB system have anti-nausea/anti-emetic potential. The pre-clinical anti-nausea/anti-emetic evidence highlights the need for further evaluation of cannabinoids and manipulations of eCBs and other fatty acid amides in clinical trials.

Restraint stress exacerbates indomethacin-induced gastric antral ulcers by gastroparesis via activation of corticotropin-releasing factor 2 receptors in refed mice

We examined the effects of stress on the indomethacin (IND)-induced gastric antral ulcer formation in refed mice. Male mice underwent refeeding of diet for 2 hours after a fast for 22 hours, followed by IND injection; the lesion index was measured 24 hours later. Mice also underwent a defined diet for 2 hours following a fast for 22 hours, and the stomachs were collected 1.5 hours later. We then measured the volume and the bile acid concentrations of the gastric contents. Mice underwent restraint stress (RS) in a cylindrical plastic tube for 60 minutes, or treatment with corticotropin-releasing factor (CRF), following refeeding of diet for 2 hours. We then examined the effects of RS and CRF on the lesion index, gastric emptying, and duodenogastric bile reflux. The effects of receptor antagonists for CRF2 (astressin-2B), CRF1, 5-hydroxytriptamine 3 (ondansetron), dopamine 2 (haloperidol), and cholecystokinin 1 (lorglumide) on the effects of RS or CRF were examined. IND (10 mg/kg, s.c.) induced pronounced lesions in the antrum. RS and CRF (30 μg/kg, i.p.) increased the severity of the antral lesions accompanied by an increase in gastric volume and concentration of bile acids. These effects of RS and peripheral CRF were significantly inhibited by pretreatment with astressin-2B, ondansetron, haloperidol, and lorglumide, but not by the CRF1 receptor antagonist. This study suggests that RS increases the severity of IND-induced gastric antral ulcers associated with gastroparesis and enhanced bile reflux via activation of peripheral CRF2, 5-hydroxytriptamine 3, and cholecystokinin 1 receptors with central dopamine 2 receptor, but not by CRF1 receptor. SIGNIFICANCE STATEMENT: Restraint stress worsens nonsteroidal anti-inflammatory drugs-induced antral ulcers due to inhibition of gastric motility and increase in bile reflux via activation of peripheral corticotropin-releasing factor 2, 5-hydroxytriptamine 3, and cholecystokinin 1 receptors with central dopamine 2 receptor. Our study predicts that gastroparesis induced by antimotility drugs, stress, functional dyspepsia, Parkinson disease, diabetes mellitus, and other conditions worsens, and gastroprokinetic agents prevent the severity of nonsteroidal anti-inflammatory drugs-induced gastric antral ulcers.

Efficacy of preoperative prophylactic application of betamethasone on postoperative nausea and vomiting in patients undergoing total knee arthroplasty: a prospective randomized controlled trial

Background

The demand for total knee arthroplasty (TKA) is increasing, yet postoperative nausea and vomiting (PONV) significantly hinder patient recovery. Preoperative prophylactic administration of glucocorticoids can alleviate PONV, with betamethasone showing promising results in breast and cardiac surgeries. However, its efficacy in TKA patients remains unclear. This study evaluates the efficacy and safety of preoperative betamethasone for PONV in TKA patients through a prospective randomized controlled trial (RCT).

Materials and methods

In this trial, 124 patients were randomly assigned to receive either 2 mL of normal saline (control group) or 2 mL of betamethasone sodium phosphate (10.52 mg total dose; experimental group) 10 min before anesthesia induction. Primary outcomes included nausea severity, vomiting frequency, and antiemetic use, while secondary outcomes were pain scores, knee range of motion, blood glucose, IL-6, CRP, ESR, and adverse reactions.

Results

Results showed the experimental group had significantly lower nausea severity at 2, 4, 6, 12, and 24 h post-surgery compared to controls. The average frequency of vomiting in the experimental group (0.060 ± 0.307) was lower than that in the control group (0.390 ± 0.662), with a statistical difference (P < 0.001). The postoperative use of metoclopramide in the experimental group (0.480 ± 2.163) was lower than that in the control group (4.520 ± 6.447), and there was a statistical difference between the two groups (P < 0.001). CRP in the experimental group on the second day after surgery (45.741 ± 47.044) was lower than that in the control group (65.235 ± 50.970), with a statistical difference (P = 0.014). IL-6 in the experimental group was lower on the first (51.853 ± 67.202) and second postoperative days (25.143 ± 31.912) than that in the control group on the first (79.477 ± 97.441) and second postoperative days (38.618 ± 36.282), with statistical differences (P = 0.039, P = 0.006). There was no significant difference in postoperative knee pain, knee range of motion, blood glucose, ESR, and adverse reactions between the two groups.

Conclusion

Our prospective RCT demonstrates that preoperative betamethasone is effective and safe for reducing PONV in TKA patients, suggesting a new clinical approach for prophylactic treatment of PONV post-TKA.

Determination of osimertinib concentration in rat plasma and lung/brain tissues

OBJECTIVES

The aim of this study was to establish an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the detection of osimertinib in rat plasma, lung and brain tissues.

METHODS

Forty-eight rats were randomly divided into an experimental group (receiving osimertinib at doses of 5, 8, and 10 mg/kg) and a control group. After continuous intragastric administration for 15 days, samples of blood, lung, and brain tissue were collected. Chromatographic separation was achieved using a BEH C18 column with gradient elution, employing a mobile phase of water (containing 0.1% (v/v) formic acid) and acetonitrile. The concentration of osimertinib in the samples was determined using an AB SCIEX 5500 triple quadrupole mass spectrometer operated in positive electrospray ionization (ESI+) and multiple reaction monitoring (MRM) mode.

RESULTS

A UPLC-MS/MS analytical method for determining osimertinib concentrations was successfully established and validated. A linear relationship was observed for osimertinib concentrations in plasma within the range of 1-300 ng/mL, and in lung and brain tissues within the range of 0.5-50 ng/mL. The selectivity, accuracy, precision, matrix effect, extraction recovery, and stability all meet the requirements of methodological validation criteria.

CONCLUSIONS

A rapid and sensitive UPLC-MS/MS method was developed and validated for quantifying osimertinib concentrations in rat plasma, lung, and brain tissues, providing a valuable tool for pharmacokinetic and tissue distribution studies.

Beyond classical immunity: Mast cells as signal converters between tissues and neurons

Mast cells are regarded as effectors in immune defense against parasites and venoms and play an essential role in the pathology of allergic diseases. More recently, mast cells have been shown to receive stimuli derived from type 2 immunity, tissue damage, stress, and inflammation. Mast cells then rapidly convert these diverse signals into appropriate, organ-specific protective reflexes that can limit inflammation or reduce tissue damage. In this review, we consider functions of mast cells in sensations-such as pain, itch, and nausea-arising from tissue insults and inflammation and the ensuing protective responses. In light of emerging data highlighting the involvement of mast cells in neuroimmune communication, we also propose that mast cells are "signal converters" linking immunological and tissue states with nervous system responses.

Comparison of Phenylephrine Bolus and Infusion Regimens on Maternal and Fetal Outcomes During Cesarean Delivery: A Systematic Review and Meta-Analysis

BACKGROUND

A systematic review and meta-analysis was conducted to compare phenylephrine boluses versus prophylactic infusion in parturients undergoing cesarean delivery under spinal or combined spinal-epidural anesthesia on feto-maternal outcomes.

METHODS

Medline, Embase, Cochrane, and US Clinical registry databases were searched. Studies comparing phenylephrine boluses (both therapeutic and prophylactic) with infusion (both fixed- and variable-rate) assessing various feto-maternal outcomes were included. The primary outcome was the incidence of maternal hypotension. Secondary maternal outcomes included the incidence of reactive hypertension, bradycardia, nausea, or vomiting; secondary neonatal outcomes included umbilical arterial pH, partial pressure of oxygen (paO2), umbilical venous pH, fetal acidosis, Apgar Scores at 1 and 5 minutes. All outcomes were quantitatively analyzed using the random effects model. Risk of bias was assessed using the Cochrane Collaboration R0B 2.0 tool.

RESULTS

We included 15 studies with 2153 parturients. The parturients receiving phenylephrine bolus during cesarean delivery under spinal or combined spinal-epidural anesthesia had a significant increase in the incidence of predelivery hypotension compared to phenylephrine infusion (risk ratio [RR], 2.34, 95% confidence interval [CI], 1.72-3.18). Reactive hypertension (RR, 0.48, 95% CI, 0.29-0.79) and bradycardia (RR, 0.57, 95% CI, 0.41-0.79) were less common in the parturients receiving phenylephrine bolus; whereas, vomiting (RR, 2.15, 95% CI, 1.53-3.03) was more common compared to the infusion group. No statistically significant difference was observed in the incidence of nausea or any fetal outcomes (umbilical artery pH, paO2, umbilical venous pH, fetal acidosis, and Apgar scores at 1 and 5 minutes) between either of the groups. Three studies had a high risk of bias.

CONCLUSIONS

A prophylactic phenylephrine infusion significantly reduces the incidence of predelivery hypotension in parturients undergoing cesarean delivery under neuraxial anesthesia in comparison to the therapeutic or prophylactic phenylephrine bolus group. A prophylactic phenylephrine infusion may be considered in all parturients without preexisting hypertensive disorder or cardiovascular disorders to reduce the risk of predelivery hypotension. More evidence is needed to guide optimal hemodynamic management for patients with hypertensive or cardiovascular disorders.

Safety pharmacology of acute mescaline administration in healthy participants

AIMS

Psychedelics, including mescaline, may serve as novel treatments for depression and anxiety. However, data is scarce on the safety of mescaline.

METHODS

The present pooled analysis included two double-blind, randomized, placebo-controlled studies with a total of 48 participants and 96 mescaline administrations. Single oral-dose administrations (n = 16/dose) of mescaline at doses of 100-800 mg were used. Acute subjective and autonomic effects and acute and subacute adverse effects were recorded. Liver and kidney function, blood cell counts, and "flashbacks" were documented at the end of the studies.

RESULTS

Positive subjective effects dose-dependently increased and were higher than negative subjective effects for all mescaline doses. Autonomic effects increased moderately. Systolic blood pressure remained < 180 mmHg in all participants. Of all mescaline administrations, diastolic blood pressure > 100 mmHg was measured in 6%, heart rate > 100 beats/min was measured in 3% and body temperature > 38 °C was measured in 5%. The total number of acute adverse effects was 51, 12, 179, 143, 165 and 180 at 100, 200, 300, 400, 500 and 800 mg doses of mescaline, respectively. Nausea was dose-limiting. Kidney and liver function and blood cell counts remained normal. "Flashbacks" were reported after 2% of all mescaline administrations.

CONCLUSIONS

These findings suggest that the administration of single mescaline doses up to 800 mg are safe in a controlled clinical setting with regard to acute psychological and physical harm in healthy participants.

Assessment of antiemetic activity of dihydrocoumarin: In vivo and in silico approaches on receptor binding affinity and modulatory effects

Dihydrocoumarin (DCN) is a natural compound widely used in the flavor industry and has antioxidant and anti-inflammatory properties. However, its potential antiemetic effects on gastrointestinal disturbances remain untested. This study emphasizes assessing the antiemetic properties of the natural aromatic compound DCN using copper sulfate (CuSO4.5H2O)-induced emetic model on chicks, and an in silico approach was also adopted to estimate the possible underlying mechanisms. Two doses (25 and 50 mg/kg b.w.) of DCN and several referral drugs considered positive controls (PCs), including domperidone (6 mg/kg), hyoscine (21 mg/kg), aprepitant (16 mg/kg), diphenhydramine (10 mg/kg), and ondansetron (5 mg/kg), were orally administered to chicks. The vehicle was provided as the control group. Co-treatments of DCN with referral drugs were also provided to chicks to evaluate the modulatory action of the test compound. According to the results, DCN delayed the emetic onset and decreased the frequency of retches in a dose-dependent manner compared to the vehicle group. DCN (50 mg/kg) represented a notable delayed latency period (61.17 ± 4.12 s) and a diminished number of retchings (17.67 ± 1.82 times) compared to the control group. Further, in the co-treatments, DCN increased the latency period and reduced the number of retches, except for domperidone. In the in silico investigation, DCN showed notable binding affinity toward the D2 (-7 kcal/mol), H1 (-7.5 kcal/mol), and M5 (-7 kcal/mol) receptors in the same binding site as the referral ligand. Our research indicates that DCN has mild antiemetic properties by interacting with the D2, H1, and M5 receptors. Therefore, several pre-clinical and clinical studies are necessary to assess the effectiveness and safety profile of this food ingredient.

Postoperative Complications

Surgery under anesthesia poses a significant stress to the body, and postoperative complications occur in up to 20% of cases. An understanding of postoperative complications, including assessment of patients at risk, risk mitigation, early recognition, and evidence-based treatment, is essential to provide high-value health care. Common postoperative complications reviewed in this article include fever, cerebrovascular accident, nausea and vomiting, ileus, and urinary retention, including discussion of pathophysiology, prevention, and treatment.

Staphylococcus aureus in Dairy Industry: Enterotoxin Production, Biofilm Formation, and Use of Lactic Acid Bacteria for Its Biocontrol

Staphylococcus aureus is a well-known pathogen capable of producing enterotoxins during bacterial growth in contaminated food, and the ingestion of such preformed toxins is one of the major causes of food poisoning around the world. Nowadays 33 staphylococcal enterotoxins (SEs) and SE-like toxins have been described, but nearly 95% of confirmed foodborne outbreaks are attributed to classical enterotoxins SEA, SEB, SEC, SED, and SEE. The natural habitat of S. aureus includes the skin and mucous membranes of both humans and animals, allowing the contamination of milk, its derivatives, and the processing facilities. S. aureus is well known for the ability to form biofilms in food processing environments, which contributes to its persistence and cross-contamination in food. The biocontrol of S. aureus in foods by lactic acid bacteria (LAB) and their bacteriocins has been studied for many years. Recently, LAB and their metabolites have also been explored for controlling S. aureus biofilms. LAB are used in fermented foods since in ancient times and nowadays characterized strains (or their purified bacteriocin) can be intentionally added to prolong food shelf-life and to control the growth of potentially pathogenic bacteria. Regarding the use of these microorganism and their metabolites (such as organic acids and bacteriocins) to prevent biofilm development or for biofilm removal, it is possible to conclude that a complex network behind the antagonistic activity remains poorly understood at the molecular level. The use of approaches that allow the characterization of these interactions is necessary to enhance our understanding of the mechanisms that govern the inhibitory activity of LAB against S. aureus biofilms in food processing environments.

Transient bradycardia during local anaesthesia to the oral cavity under intravenous sedation and its associate factors: a prospective observational study

BACKGROUND

Local anaesthesia in dental procedures is generally safe, although the occurrence of transient bradycardia (TB) has occasionally been reported. TB is often associated with two reflexes, the trigeminal cardiac reflex (TCR) and the vasovagal reflex (VVR) and is characterised by a rapid decrease in heart rate (HR) and blood pressure (BP). The prevalence of TCR is considered low, and its predictors have not been thoroughly investigated, although an association with the gag reflex has been suggested in recent years.

METHODS

This prospective study assessed TB occurrence during local anaesthesia and its potential associated factors. A comprehensive questionnaire was used to categorise discomforts during dental treatment, and various anxiety scales were used to measure patients' anxiety levels. We investigated HR variability during local anaesthesia administration under sedation and the association between the incidence of TB and gag reflex. Subsequently, logistic regression analysis was performed to assess factors associated with TB occurrence.

RESULTS

The prospective analysis included 188 patients of 234 initial patients. The analysis revealed a high TB incidence rate of 41% during local anaesthesia administration under sedation. No severe hypotensive events occurred, indicating a relatively benign nature of TB during local anaesthesia. TB occurrence was significantly higher in the group of patients with the gag reflex. Further analysis revealed that both gag reflex and trait anxiety were significantly associated with TB occurrence, whereas dental phobia did not directly correlate with TB.

CONCLUSION

This study highlights the prominent occurrence of TB during local anaesthesia in dental treatment, which is primarily attributed to TCR activation. The identification of gag reflex and trait anxiety as independent factors associated with TB development may pave the way for TB prevention measures. Further research is required to clarify the mechanisms of TCR and perform safer dental procedures under sedation. Future studies should also aim to elucidate the precise mechanisms underlying TB during local anaesthesia through direct measurements of neural activity. A better understanding of TB in dentistry is crucial for improving patient safety and optimising dental practice protocols.

The Gut Microbial Lipid Metabolite 14(15)-EpETE Inhibits Substance P Release by Targeting GCG/PKA Signaling to Relieve Cisplatin-Induced Nausea and Vomiting in Rats

Chemotherapy-induced nausea and vomiting (CINV) is a debilitating side effect related to activation of substance P (SP). SP activation can result from dysregulation of the gut-brain axis, and also from activation of protein kinase A signaling (PKA) signaling. In this study, we connected these factors in an attempt to unveil the mechanisms underlying CINV and develop new therapeutic strategies. Female rats were injected with cisplatin (Cis) to induce pica. Fecal samples were collected before/after injection, and subjected to lipid metabolomics analysis. In another portion of pica rats, the PKA inhibitor KT5720 was applied to investigate the involvement of PKA signaling in CINV, while fecal microbiota transplantation (FMT) was implemented to verify the therapeutic effect of the lipid metabolite 14(15)-EpETE. Pica symptoms were recorded, followed by ileal histological examination. The targeting relationship between 14(15)-EpETE and glucagon was determined by bioinformatics. SP and glucagon/PKA signaling in rat ileum, serum, and/or brain substantia nigra were detected by immunohistochemistry, enzyme-linked immunosorbent assay, and/or western blot. The results showed a significantly lower level of 14(15)-EpETE in rat feces after Cis injection. KT5720 treatment alleviated Cis-induced pica symptoms, ileal injury, SP content increase in the ileum, serum, and brain substantia nigra, and ileal PKA activation in rats. The ileal level of glucagon was elevated by Cis in rats. FMT exerted an effect similar to that of KT5720 treatment, relieving the Cis-induced changes, including ileal glucagon/PKA activation in rats. Our findings demonstrate that FMT restores 14(15)-EpETE production, which inhibits SP release by targeting GCG/PKA signaling, ultimately mitigating CINV.

What lurks beneath the symptom? Why more basic scientists are needed in cancer supportive care and survivorship research

With a growing population of people living with and beyond cancer, a larger portion of cancer research has shifted to ensuring that these people not only survive but survive well, and so supportive oncology has emerged as a critical component of modern cancer care. However, research and advancements in supportive care strategies have largely centered around symptom management, without an appreciation for the physiological mechanisms underlying the symptom. By placing a greater emphasis on understanding the pathophysiological mechanisms that lurk beneath the symptom in supportive care and survivorship research, superior symptom control and greater improvements to quality of life, through the development of targeted interventions, can be achieved.

Long-term complications in acute porphyria

New treatment options and low attack-related mortality have changed the life expectancy of patients with acute porphyria (AP) to that of the general population. Clinicians should therefore be aware of the long-term complications of AP, which typically include chronic neuropathy and encephalopathy, high blood pressure and porphyria-associated kidney disease. Patients have an increased risk of primary liver cancer (PLC), but no increased risk of non-hepatic cancers. Chronic pain occurs in patients with recurrent attacks, combined with chronic fatigue and nausea, leading to poor quality of life. Patients with sporadic attacks may also have chronic symptoms, which should be distinguished from mild recurrent attacks and treated appropriately. Sequels of acute polyneuropathy after an attack should be distinguished from ongoing chronic polyneuropathy, as the management is different. Overestimation of chronic neuropathy or encephalopathy caused by AP should be avoided, and other causes should be treated accordingly. Prevention of recurrent attacks is the best strategy for managing chronic comorbidities and should be actively accomplished. Hormonal interventions in female patients, or in severe cases, prophylactic givosiran or haematin, may be helpful before liver transplantation to prevent recurrent attacks. Regular monitoring can be personalised according to the patient's age, comorbidities and AP activity. Blood pressure, renal function and cardiovascular risk factors should be monitored annually in patients with previous symptoms. Appropriate medication and lifestyle management, including nutrition and hydration, are necessary to prevent complications. As PLC is common, especially in patients with acute intermittent porphyria, bi-annual surveillance after the age of 50 is important.

Disgust as a primary emotional system and its clinical relevance

This paper advocates for considering disgust as a primary emotional system within Panksepp's Affective Neuroscience framework, which has the potential to improve the efficacy of psychotherapy with obsessive-compulsive disorder, hypochondriasis, and emetophobia. In 2007, Toronchuk and Ellis provided comprehensive evidence that DISGUST system, as they defined it, matched all Panksepp's criteria for a primary emotional system. A debate ensued and was not unambiguously resolved. This paper is an attempt to resume this discussion and supplement it with the data that accumulated since then on DISGUST's relationship with the immune system and the role of DISGUST dysregulation in psychopathology. We hope that renewed research interest in DISGUST has the potential to improve clinical efficacy with hard-to-treat conditions.

Effect of Prophylactic Tropisetron on Post-Operative Nausea and Vomiting in Patients Undergoing General Anesthesia: Systematic Review and Meta-Analysis with Trial Sequential Analysis

This systematic review and meta-analysis of randomized controlled trials (RCTs) with trial sequential analysis (TSA) aimed to comprehensively evaluate and compare the efficacy of the prophylactic administration of tropisetron in the prevention of the incidence of post-operative nausea and vomiting (PONV) in patients undergoing surgery under general anesthesia. This study was registered with PROSPERO (CRD42024372692). RCTs comparing the efficacy of the perioperative administration of tropisetron with that of a placebo, other anti-emetic agents, or a combination of anti-emetic injections were retrieved from the databases of Ovid-MEDLINE, Ovid-EMBASE, the Cochrane Central Register of Controlled Trials, and Google Scholar. The frequency of rescue anti-emetic use (RA) and the incidence of PON, POV, and PONV (relative risk [RR]: 0.718; 95% confidence interval [CI] 0.652-0.790; I2 = 0.0, RR: 0.587; 95% CI 0.455-0.757; I2 = 63.32, RR: 0.655; 95% CI 0.532-0.806; I2 = 49.09, and RR: 0.622; 95% CI 0.552-0.700; I2 = 0.00, respectively) in the tropisetron group were lower than those in the control group; however, the incidence of complete response (CR) was higher in the tropisetron group (RR: 1.517;95% CI 1.222-1.885; I2 = 44.14). TSA showed the cumulative Z-curve exceeded both the conventional test and trial sequential monitoring boundaries for RA, PON, POV, and PONV between the tropisetron group and the control group. Thus, the prophylactic administration of tropisetron exhibited superior efficacy in the prevention of PON, POV, and PONV. Furthermore, a lower incidence of RA and a higher incidence of CR were observed with its use.

An overview of 6-shogaol: new insights into its pharmacological properties and potential therapeutic activities

Ginger (Zingiber officinale Roscoe) has traditionally been used as a cooking spice and herbal medicine for treating nausea and vomiting. More recently, ginger was found to effectively reduce the risk of diseases such as gastroenteritis, migraine, gonarthritis, etc., due to its various bioactive compounds. 6-Shogaol, the pungent phenolic substance in ginger, is the most pharmacologically active among such compounds. The aim of the present study was to review the pharmacological characteristic of 6-shogaol, including the properties of anti-inflammatory, antioxidant and antitumour, and its corresponding molecular mechanism. With its multiple mechanisms, 6-shogaol is considered a beneficial natural compound, and therefore, this review will shed some light on the therapeutic role of 6-shogaol and provide a theoretical basis for the development and clinical application of 6-shogaol.

Exploring the role of ghrelin and des-acyl ghrelin in chemotherapy-induced nausea and vomiting

Ghrelin and its mimetics have been shown to reduce cisplatin-induced emesis in preclinical studies using ferrets and shrews. This study investigated the effectiveness of ghrelin and des-acyl ghrelin (DAG) in antagonizing cisplatin-induced emesis and physiological changes indicative of nausea in Suncus murinus. Animals implanted with radiotelemetry devices were administered ghrelin (0.2, 1.0, and 5.0 μg/day), DAG (0.2, 1.0, and 5.0 μg/day), or saline (14 μL/day) intracerebroventricularly 4 days before and 3 days after treatment with cisplatin (30 mg/kg). At the end, the anti-apoptotic potentials of ghrelin and DAG were assessed by measuring Bax expression and cytochrome C activity. Neurotransmitter changes in the brain were evaluated using liquid chromatography-mass spectrometry analysis. Ghrelin and DAG reduced cisplatin-induced emesis in the delayed (24-72 h) but not the acute phase (0-24 h) of emesis. Ghrelin also partially reversed the inhibitory effects of cisplatin on food intake without affecting gastrointestinal myoelectrical activity or causing hypothermia; however, ghrelin or DAG did not prevent these effects. Ghrelin and DAG could attenuate the cisplatin-induced upregulation of Bax and cytochrome C in the ileum. Cisplatin dysregulated neurotransmitter levels in the frontal cortex, amygdala, thalamus, hypothalamus, and brainstem, and this was partially restored by low doses of ghrelin and DAG. Our findings suggest that ghrelin and DAG exhibit protective effects against cisplatin-induced delayed emesis. The underlying antiemetic mechanism may involve GHSR and/or unspecified pathways that modulate the neurotransmitters involved in emesis control in the brain and an action to attenuate apoptosis in the gastrointestinal tract.

Lower Cervical Dural Arteriovenous Fistula with a "Skip Lesion" in the Brainstem: A Case Report

Spinal dural arteriovenous fistulas (SDAVFs) are rare vascular malformations that can occur anywhere in the spine. Most SDAVFs lead to slow aggressive myelopathy due to venous congestion at a level adjacent to the shunt point. However, rare cases of localized brainstem edema without spinal cord lesions have been reported. In this study, we present a case of a lower cervical SDAVF that showed localized congestive edema of the medulla in the absence of an edematous change in the cervical spinal cord. The patient was a 57-year-old woman who experienced vertigo and vomiting without myelopathy that did not improve with conservative treatment. Magnetic resonance imaging (MRI) revealed high signal intensity in the left medulla on T2-weighted imaging (T2WI), while angiography revealed an SDAVF at the right C8 segmental level supplied by the right thyrocervical trunk. She underwent surgical interruption of the draining vein, which led to a rapid improvement in her symptoms. A subsequent follow-up MRI confirmed resolution of both the medullary edema and the dilated draining vein. SDAVFs may cause vertigo and vomiting, which are brainstem symptoms. Early diagnosis and surgical intervention are crucial for successful treatment outcomes.

Effect of Weighted Blanket Versus Traditional Practices on Anxiety and Pain in Patients Undergoing Elective Surgery: A Multicenter Randomized Controlled Trial

Perioperative anxiety is common in surgical patients and linked to poor outcomes. This multicenter randomized controlled trial assessed the effect of the use of a warm weighted blanket on presurgical anxiety and pain, as well as postsurgical restlessness, nausea, and vomiting. Levels of anxiety and pain were measured in adult patients using a 100-point visual analog scale before elective surgery. Patients received either a warm weighted blanket (n = 74) or a traditional sheet or nonweighted blanket (n = 74). Patients in the intervention group had significantly lower preoperative anxiety scores (mean [SD] = 26.28 [25.75]) compared to the control group (mean [SD] = 38.73 [30.55], P = .008). However, the intervention had no significant effect on presurgical pain or postsurgical nausea, vomiting, or restlessness. These results suggest that weighted blankets reduce preoperative anxiety in adult patients.

Electroencephalographic Changes in Pregnant Women with Hyperemesis Gravidarum: A Case-Control Study

OBJECTIVE

Electroencephalogram (EEG), which is frequently used in the clinical practice of neurology, has also been investigated in eating disorders and some cortical dysfunctions have been reported. Based on this, we aimed to investigate EEG changes in pregnant women with hyperemesis gravidarum (HEG).

MATERIALS AND METHODS

This case-control study was conducted on 66 pregnant women who applied to the Umraniye Training and Research Hospital, Department of Obstetrics and Gynecology. The study group consisted of 34 pregnant women diagnosed with HEG. The control group consisted of 32 healthy pregnant women who were matched with the HEG group in terms of age and gestational week. EEGs of the participants were performed with a Micromed Brain Rapid EEG device in the Neurology Department of Umraniye Training and Research Hospital. In EEGs, all channels were selected as bipolar and samples of 18 channels (Fp2-F4, F4-C4, C4-P4, P4-O2, Fp2-F8, F8-T4, T4-T6, T6-O2, Fz-Cz, Cz-Pz, Fp1-F3, F3-C3, C3-P3, P3-O1, Fp1-F7, F7-T3, T3-T5, and T5-O1) were obtained. EEG signals were sampled with a sampling frequency of 200 Hz and digitized with 12-bit resolution. EEG signals were converted to EDF (European Data Format) extension files using the MATLAB software program and analyzed using statistical features on the time and frequency axis. HEG and control groups were compared in terms of signals obtained from these 18 selected channels.

RESULTS

Both groups were similar in terms of mean age, gestational age, and parity (p>0.05). Among the 18 channels, significant changes were detected between the two groups only in the theta, beta, and gamma bands in the C4-P4 channel and the delta, beta, and gamma bands in the T4-T6 channel (p<0.05). No significant changes were detected in the channels and bands.

CONCLUSION

Theta, beta, and gamma band abnormalities in the centro-parietal area of the right hemisphere and delta, beta, and gamma band abnormalities in the temporal area of the right hemisphere were observed on HEG. However, it is unclear whether abnormalities in EEG are primary changes responsible for the development of HEG or secondary to metabolic and hormonal changes resulting from HEG itself.

A nurse-led multidomain intervention to improve the management of chemotherapy-induced nausea and vomiting in patients with head and neck cancers: A randomized controlled trial

PURPOSE

This study aimed to investigate the effect of a nurse-led multidomain intervention on chemotherapy induced nausea and vomiting (CINV) in patients with head and neck squamous cell carcinomas (HNSCC).

METHODS

Ninety-two HNSCC patients who received cisplatin-based chemotherapy were divided into intervention group (n = 45) and control group (n = 47). The control group received usual care of CINV, which consisted of administration of antiemetics according to physicians' preference, education about CINV control and dietary recommendations provided by primary nurses. The intervention group received nurse-led, evidence-based multidomain management, including nurse-led CINV risk factors assessment, education on prevention and control of CINV, antiemetics following guidelines, dietary strategies, and relaxation therapy. The number of patients who experienced CINV was collected. The severity of CINV was graded according to the Common Terminology Criteria for Adverse Events v3.0. The influence of CINV on patient's quality of life was assessed by the Functional Living Index-Emesis (FLIE).

RESULTS

The incidence and the severity of nausea and vomiting in the intervention group were significantly lower than those in the control group within 5 days after chemotherapy, and the scores of the dimension of nausea and vomiting in the intervention group were significantly higher than those in the control group [63.00 (50.00-63.00) vs 40.00(28.00-63.00), 63.00(63.00-63.00) vs 63.00 (43.00-63.00)], the differences were statistically significant (P < 0.05).

CONCLUSIONS

Nurse-led multidomain intervention can reduce the incidence and the severity of CINV in patients with HNSCC who were treated with cisplatin-based chemotherapy, and thus reduced the influence of CINV on patients' quality of life.

THE CLINICAL TRIAL REGISTRATION NUMBER

NCT05792228.

A Comparative Study of the Antiemetic Effects of α2-Adrenergic Receptor Agonists Clonidine and Dexmedetomidine against Diverse Emetogens in the Least Shrew (Cryptotis parva) Model of Emesis

In contrast to cats and dogs, here we report that the α2-adrenergic receptor antagonist yohimbine is emetic and corresponding agonists clonidine and dexmedetomidine behave as antiemetics in the least shrew model of vomiting. Yohimbine (0, 0.5, 0.75, 1, 1.5, 2, and 3 mg/kg, i.p.) caused vomiting in shrews in a bell-shaped and dose-dependent manner, with a maximum frequency (0.85 ± 0.22) at 1 mg/kg, which was accompanied by a key central contribution as indicated by increased expression of c-fos, serotonin and substance P release in the shrew brainstem emetic nuclei. Our comparative study in shrews demonstrates that clonidine (0, 0.1, 1, 5, and 10 mg/kg, i.p.) and dexmedetomidine (0, 0.01, 0.05, and 0.1 mg/kg, i.p.) not only suppress yohimbine (1 mg/kg, i.p.)-evoked vomiting in a dose-dependent manner, but also display broad-spectrum antiemetic effects against diverse well-known emetogens, including 2-Methyl-5-HT, GR73632, McN-A-343, quinpirole, FPL64176, SR141716A, thapsigargin, rolipram, and ZD7288. The antiemetic inhibitory ID50 values of dexmedetomidine against the evoked emetogens are much lower than those of clonidine. At its antiemetic doses, clonidine decreased shrews' locomotor activity parameters (distance moved and rearing), whereas dexmedetomidine did not do so. The results suggest that dexmedetomidine represents a better candidate for antiemetic potential with advantages over clonidine.

Cholecystokinin-Induced Duodenogastric Bile Reflux Increases the Severity of Indomethacin-Induced Gastric Antral Ulcers in Re-fed Mice

BACKGROUND/AIMS

We examined the involvement of cholecystokinin (CCK) in the exacerbation of indomethacin (IND)-induced gastric antral ulcers by gastroparesis caused by atropine or dopamine in mice.

METHODS

Male mice were fed for 2 h (re-feeding) following a 22-h fast. Indomethacin (IND; 10 mg/kg, s.c.) was administered after re-feeding; gastric lesions were examined 24 h after IND treatment. In another experiment, mice were fed for 2 h after a 22-h fast, after which the stomachs were removed 1.5 h after the end of the feeding period. Antral lesions, the amount of gastric contents, and the gastric luminal bile acids concentration were measured with or without the administration of the pro- and antimotility drugs CCK-octapeptide (CCK-8), atropine, dopamine, SR57227 (5-HT3 receptor agonist), apomorphine, lorglumide (CCK1 receptor antagonist), ondansetron, and haloperidol alone and in combination.

RESULTS

IND produced severe lesions only in the gastric antrum in re-fed mice. CCK-8, atropine, dopamine, SR57227 and apomorphine administered just after re-feeding increased bile reflux and worsened IND-induced antral lesions. These effects were significantly prevented by pretreatment with lorglumide. Although atropine and dopamine also increased the amount of gastric content, lorglumide had no effect on the delayed gastric emptying provoked by atropine and dopamine. Both ondansetron and haloperidol significantly inhibited the increase of bile reflux and the exacerbation of antral lesions induced by atropine and dopamine, respectively, but did not affect the effects of CCK-8.

CONCLUSIONS

These results suggest that CCK-CCK1 receptor signal increases bile reflux during gastroparesis induced by atropine and dopamine, exacerbating IND-induced antral ulcers.

Association between preoperative lumbar skeletal muscle index and postoperative nausea and vomiting in patients undergoing pylorus-preserving pancreatoduodenectomy: a retrospective study

BACKGROUND

Sarcopenia is associated with postoperative complications; however, its impact on the quality of postoperative recovery, such as postoperative nausea and vomiting (PONV) and pain, remains unclear. We investigated the association of preoperative lumbar skeletal muscle mass index (LSMI) with PONV, postoperative pain, and complications.

METHODS

Medical records of 756 patients who underwent pylorus-preserving pancreatoduodenectomy (PPPD) were retrospectively reviewed. The skeletal muscle areas were measured on abdominal computed tomography (CT) images. LSMI was calculated by dividing the skeletal muscle area by the square of the patient's height. We analyzed the correlations between preoperative LSMI calibrated with confounding variables and PONV scores, PONV occurrence, pain scores, rescue analgesic administration, postoperative complications, and length of hospital stay.

RESULTS

The median (1Q, 3Q) LSMI was 47.72 (40.74, 53.41) cm2/m2. The incidence rates of PONV according to time period were as follows: post-anesthesia care unit, 42/756 (5.6%); 0-6 h, 54/756 (7.1%); 6-24 h, 120/756 (15.9%); 24-48 h, 46/756 (6.1%); and overall, 234/756 (31.0%). The incidence of PONV was inversely correlated with LSMI 24-48 h post-surgery and overall. LSMI and PONV scores were negatively associated 6-24 h and 24-48 h post-surgery. There was no association between LSMI and postoperative pain scores, rescue analgesic administration, complications, or length of hospital stay.

CONCLUSIONS

Preoperative LSMI was associated with PONV in patients undergoing PPPD. Therefore, LSMI measured on preoperative abdominal CT can be a predictive indicator of PONV. Appropriate PONV prophylaxis is necessary in patients with low LSMI before PPPD.

Comparison of Nausea and Vomiting Incidence After Laparoscopic Cholecystectomy With Pretreatment With Haloperidol and Ondansetron: A Randomization Clinical Trial Study

OBJECTIVE

Nausea and vomiting after surgery are the most common complications. Therefore, we performed this study to compare the effect of ondansetron and haloperidol on nausea and vomiting after laparoscopic cholecystectomy.

PATIENTS AND METHODS

In this randomized clinical trial, 60 patients candidates for elective laparoscopic cholecystectomy were allocated to haloperidol (0.05 mg/kg, n = 30) and ondansetron (0.15 mg/kg, n = 30) groups. An Ocular Analog Scale was used to assess postoperative nausea and vomiting. Every 15 minutes in the recovery room, heart rate and blood pressure were measured up to 6 hours after surgery. In addition, patient satisfaction was assessed postoperatively.

RESULTS

Haloperidol and ondansetron have the same effect on postoperative nausea and vomiting in the recovery room and ward. It was found that the trend of Visual Analog Scale variable changes in the recovery room was similar in the haloperidol and ondansetron group ( P = 0.58); it was also true for the ward ( P = 0.79). Comparing the length of stay in a recovery room in the 2 groups was not statistically significant ( P = 0.19). In addition, the 2 groups did not differ in satisfaction postoperatively ( P = 0.82).

CONCLUSION

Haloperidol and ondansetron had an equal effect on reducing nausea and vomiting in the recovery room and ward after laparoscopic cholecystectomy. Patient satisfaction and length of stay in the recovery room did not differ between groups.

Olanzapine as a prophylactic antiemetic for preventing postoperative nausea and vomiting after general anesthesia: A systematic review and meta-analysis

BACKGROUND

The antiemetic effectiveness of olanzapine, as a prophylactic off-label antiemetic drug, for Postoperative Nausea and Vomiting (PONV) is unknown. In this systematic review and meta-analysis, the authors evaluate the efficacy and side effects of olanzapine as a prophylactic antiemetic in adult patients who undergo general anesthesia and assess adverse effects.

METHODS

A systematic search was done on electronic bibliographic databases in July 2023. Randomized controlled trials of olanzapine as a prophylactic antiemetic for PONV in adults who underwent general anesthesia were included. The authors excluded non-RCTs and retracted studies. The authors set no date of publication or language limits. The outcomes were the incidence of PONV within 24 h postoperatively and the safety of olanzapine. The risk of bias was assessed according to the tool suggested by the National Heart, Lung, and Blood Institute.

RESULTS

Meta-analysis included 446 adult patients. Olanzapine reduced on average 38 % the incidence of PONV. The estimated risk ratio (95 % CI) of olanzapine versus control was 0.62 (0.42-0.90), p = 0.010, I2 = 67 %. In the subgroup meta-analysis, doses of olanzapine (10 mg) reduced on average 49 % of the incidence of PONV (RR = 0.51 [0.34-0.77], p = 0.001, I2 = 31 %).

CONCLUSIONS

This systematic review with meta-analysis indicated that olanzapine as a prophylactic antiemetic alone or combined with other antiemetic agents reduced the incidence of postoperative nausea and vomiting. However, this conclusion must be presented with some degree of uncertainty due to the small number of studies included. There was a lack of any evidence to draw conclusions on side effects.

Antiemetic activity of abietic acid possibly through the 5HT3 and muscarinic receptors interaction pathways

The present study was designed to evaluate the antiemetic activity of abietic acid (AA) using in vivo and in silico studies. To assess the effect, doses of 50 mg/kg b.w. copper sulfate (CuSO4⋅5H2O) were given orally to 2-day-old chicks. The test compound (AA) was given orally at two doses of 20 and 40 mg/kg b.w. On the other hand, aprepitant (16 mg/kg), domperidone (6 mg/kg), diphenhydramine (10 mg/kg), hyoscine (21 mg/kg), and ondansetron (5 mg/kg) were administered orally as positive controls (PCs). The vehicle was used as a control group. Combination therapies with the referral drugs were also given to three separate groups of animals to see the synergistic and antagonizing activity of the test compound. Molecular docking and visualization of ligand-receptor interaction were performed using different computational tools against various emesis-inducing receptors (D2, D3, 5HT3, H1, and M1-M5). Furthermore, the pharmacokinetics and toxicity properties of the selected ligands were predicted by using the SwissADME and Protox-II online servers. Findings indicated that AA dose-dependently enhances the latency of emetic retching and reduces the number of retching compared to the vehicle group. Among the different treatments, animals treated with AA (40 mg/kg) exhibited the highest latency (98 ± 2.44 s) and reduced the number of retching (11.66 ± 2.52 times) compared to the control groups. Additionally, the molecular docking study indicated that AA exhibits the highest binding affinity (- 10.2 kcal/mol) toward the M4 receptors and an elevated binding affinity toward the receptors 5HT3 (- 8.1 kcal/mol), M1 (- 7.7 kcal/mol), M2 (- 8.7 kcal/mol), and H1 (- 8.5 kcal/mol) than the referral ligands. Taken together, our study suggests that AA has potent antiemetic effects by interacting with the 5TH3 and muscarinic receptor interaction pathways. However, additional extensive pre-clinical and clinical studies are required to evaluate the efficacy and toxicity of AA.

The effect of diaphragmatic breathing on nausea, vomiting and functional status among breast cancer patients undergoing chemotherapy

PURPOSE

To examine the effect of diaphragmatic breathing (DB) on nausea, vomiting, and functional status among breast cancer patients undergoing chemotherapy in Indonesia.

METHODS

A quasi experimental study with non-equivalent pretest and posttest control group was conducted. A total of forty-eight breast cancer patients (24 DB and 24 control participants) undergoing chemotherapy participated in this study selected conveniently. DB intervention was performed to the intervention group after chemotherapy cycle twice a day for six days, meanwhile the control group received usual care. A set of questionnaires was used to collect data consisting of Patient Information Form, Rhodes Index Nausea, Vomiting and Retching (RINVR) and The Functional Living Index-Cancer (FLI-C). Data were analyzed and interpreted using Generalized Linear Model, Wilcoxon Test, Paired T Test and Mann-Whitney U test.

RESULTS

There were significant changes in RINVR mean scores for the intervention group that started on the third day after chemotherapy (p = 0.000); meanwhile, the significant changes in RINVR mean scores for the control group began on the fifth day (p = 0.000). The total score of FLI-C was significantly different between the intervention and control groups (p = 0.000).

CONCLUSION

DB could decrease nausea and vomiting, and increase functional status of breast cancer patients undergoing chemotherapy. It can be promoted as a useful low-cost self-management approach and an additional and complementary therapy to manage chemotherapy-related nausea and vomiting.

Asenapine versus olanzapine for the treatment of nausea and vomiting in patients with cancer: A retrospective study

AIM

Patients with cancer often experience nausea and vomiting (N/V), but may have difficulty using olanzapine (OLZ), a common antiemetic. Asenapine (ASE) is a multi-acting receptor-targeted antipsychotic like OLZ, although there is little evidence that ASE serves as an antiemetic. The aim of this study was to evaluate the efficacy and tolerability of ASE compared to those of OLZ for the treatment of N/V in patients with cancer.

METHODS

This retrospective study involved patients who received 5 mg ASE, 5 mg OLZ, or 2.5 mg OLZ for 2 days. Daily worst N/V was rated on a scale of 0 (none) to 3 (very much). The primary endpoint was the proportion of patients who had a response, defined as any reduction in N/V score. A complete response (CR) was defined as a score reduction to 0. Secondary endpoints included the proportion of patients with CR and adverse events.

RESULTS

Between April 2017 and March 2023, 212 patients were enrolled to receive treatment: 5 mg ASE (n = 34), 5 mg OLZ (n = 102), or 2.5 mg OLZ (n = 76). No significant differences in response rates (52.9% vs. 58.8% vs. 52.6%, p = 0.671) or secondary endpoints were observed between the groups. Patients receiving ASE were more likely to experience oral hypoesthesia (p = 0.004).

CONCLUSION

This preliminary study suggests that ASE may be effective for N/V. Further studies are required to confirm these findings.

Penehyclidine for Prevention of Postoperative Nausea and Vomiting in Patients Undergoing Gynecological Laparoscopic Surgery Under Combined Intravenous and Inhalation Anesthesia: A Randomized, Double-Blind, Placebo-Controlled Trial

Purpose

We designed this study to investigate the effect of intravenous use of penehyclidine on postoperative nausea and vomiting (PONV) after gynecological laparoscopic surgery.

Patients and Methods

Ninety-two Women Patients (Aged ≥ 18) Scheduled for Elective Gynecologic Laparoscopy Were Enrolled in the Current Study. Patients Were Equally Randomized Assigned Into Penehyclidine group (PHC group: received a bolus of penehyclidine 10 μg/kg during the induction of anesthesia, then followed by a continuous infusion of 10 μg/kg penehyclidine at a fixed rate of 2.0 mL/h in postoperative intravenous analgesia pump over 48h, 0.5 mg upper limit respectively) or Control group (received 0.9% saline in replace of penehyclidine at the same time points). The primary outcome measure was the incidence of postoperative nausea and vomiting in the postanesthesia care unit and ward area. Quality of Recovery-15 (QoR-15) scores and general comfort questionnaire (GCQ) scores were assessed on postoperative day (POD) 1, 2.

Results

Patients between two groups had comparable baseline characteristics. Compared with the Control group, the incidence and severity of PONV, postoperative nausea (PON), and postoperative vomiting (POV) were significantly lower in the PHC group at 2h (PONV: P = 0.002, P = 0.004, respectively; PON: P = 0.018, P = 0.038, respectively; POV: P = 0.011, P = 0.072, respectively), 24h (PONV: P = 0.003, P = 0.001, respectively; PON: P = 0.010, P = 0.032, respectively; POV: P = 0.006, P = 0.044, respectively), and 48h (PONV: P = 0.003, P = 0.002, respectively; PON: P = 0.007, P = 0.019, respectively; POV: P = 0.002, P = 0.013, respectively) after surgery. The QoR-15 and GCQ scores of the PHC group were significantly higher than those of the Control group at POD 1, 2 (P < 0.001; P < 0.001, respectively).

Conclusion

Our findings suggest that perioperative intravenous application of penehyclidine can effectively prevent postoperative nausea and vomiting in gynecological laparoscopic surgery patients and improve postoperative recovery.

Coexpressed δ-, μ-, and κ-Opioid Receptors Modulate Voltage-Gated Ca2+ Channels in Gastric-Projecting Vagal Afferent Neurons

Opioid analgesics are frequently associated with gastrointestinal side effects, including constipation, nausea, dysphagia, and reduced gastric motility. Though it has been shown that stimulation of opioid receptors expressed in enteric motor neurons contributes to opioid-induced constipation, it remains unclear whether activation of opioid receptors in gastric-projecting nodose ganglia neurons contributes to the reduction in gastric motility and emptying associated with opioid use. In the present study, whole-cell patch-clamp recordings were performed to determine the mechanism underlying opioid receptor-mediated modulation of Ca2+ currents in acutely isolated gastric vagal afferent neurons. Our results demonstrate that CaV2.2 channels provide the majority (71% ± 16%) of Ca2+ currents in gastric vagal afferent neurons. Furthermore, we found that application of oxycodone, U-50488, or deltorphin II on gastric nodose ganglia neurons inhibited Ca2+ currents through a voltage-dependent mechanism by coupling to the Gα i/o family of heterotrimeric G-proteins. Because previous studies have demonstrated that the nodose ganglia expresses low levels of δ-opioid receptors, we also determined the deltorphin II concentration-response relationship and assessed deltorphin-mediated Ca2+ current inhibition following exposure to the δ-opioid receptor antagonist ICI 174,864 (0.3 µM). The peak mean Ca2+ current inhibition following deltorphin II application was 47% ± 24% (EC50 = 302.6 nM), and exposure to ICI 174,864 blocked deltorphin II-mediated Ca2+ current inhibition (4% ± 4% versus 37% ± 20%). Together, our results suggest that analgesics targeting any opioid receptor subtype can modulate gastric vagal circuits. SIGNIFICANCE STATEMENT: This study demonstrated that in gastric nodose ganglia neurons, agonists targeting all three classical opioid receptor subtypes (μ, δ, and κ) inhibit voltage-gated Ca2+ channels in a voltage-dependent mechanism by coupling to Gαi/o. These findings suggest that analgesics targeting any opioid receptor subtype would modulate gastric vagal circuits responsible for regulating gastric reflexes.

A new experimental rat model of nocebo-related nausea involving double mechanisms of observational learning and conditioning

AIM

The nocebo effect, such as nausea and vomiting, is one of the major reasons patients discontinue therapy. The underlying mechanisms remain unknown due to a lack of reliable experimental models. The goal of this study was to develop a new animal model of nocebo-related nausea by combining observational learning and Pavlovian conditioning paradigms.

METHODS

Male Sprague-Dawley rats with nitroglycerin-induced migraine were given 0.9% saline (a placebo) or LiCl (a nausea inducer) following headache relief, according to different paradigms.

RESULTS

Both strategies provoked nocebo nausea responses, with the conditioning paradigm having a greater induction impact. The superposition of two mechanisms led to a further increase in nausea responses. A preliminary investigation of the underlying mechanism revealed clearly raised peripheral and central cholecystokinin (CCK) levels, as well as specific changes in the 5-hydroxytryptamine and cannabinoid systems. Brain networks related to emotion, cognition, and visceral sense expressed higher c-Fos-positive neurons, including the anterior cingulate cortex (ACC), insula, basolateral amygdala (BLA), thalamic paraventricular nucleus (PVT), hypothalamic paraventricular nucleus (PVN), nucleus tractus solitarius (NTS), periaqueductal gray (PAG), and dorsal raphe nucleus-dorsal part (DRD). We also found that nausea expectances in the model could last for at least 12 days.

CONCLUSION

The present study provides a useful experimental model of nocebo nausea that might be used to develop potential molecular pathways and therapeutic strategies for nocebo.