Commonly used antiemetics for prophylaxis of postoperative nausea and vomiting after Caesarean delivery with neuraxial morphine: a network meta-analysis.

BACKGROUND: Dopamine antagonists, 5-HT3 antagonists, and dexamethasone are frequently used in obstetrics to prevent postoperative nausea and vomiting (PONV). However, the superiority of any drug class is yet to be established. This network meta-analysis aimed to compare the efficacy of these antiemetics for PONV prophylaxis in women receiving neuraxial morphine for Caesarean delivery. METHODS: We searched PubMed, Embase, CENTRAL, Web of Science, and Wanfang Data for eligible randomised controlled trials. Primary outcomes were the incidences of postoperative nausea (PON) and postoperative vomiting (POV) within 24 h after surgery. We used a Bayesian random-effects model and calculated odds ratios with 95% credible intervals for dichotomous data. We performed sensitivity and subgroup analyses for primary outcomes. RESULTS: A total of 33 studies with 4238 women were included. In the primary analyses of all women, 5-HT3 antagonists, dopamine antagonists, dexamethasone, and 5-HT3 antagonists plus dexamethasone significantly reduced PON and POV compared with placebo, and 5-HT3 antagonists plus dexamethasone were more effective than monotherapy. In the subgroup analyses, similar results were seen in women receiving epidural morphine or intrathecal morphine alone but not in women receiving intrathecal morphine with fentanyl or sufentanil. However, most included studies had some concerns or a high risk of bias, and the overall certainty of the evidence was low or very low. CONCLUSIONS: Combined 5-HT3 antagonists plus dexamethasone are more effective than monotherapy in preventing PONV associated with neuraxial morphine after Caesarean delivery. Future studies are needed to determine the role of prophylactic antiemetics in women receiving intrathecal morphine and lipophilic opioids. SYSTEMATIC REVIEW PROTOCOL: PROSPERO CRD42023454602.

Comparison of prophylaxis strategy for postoperative nausea and vomiting and its incidence before and after the implementation of 5-hydroxytryptamine 3 in surgical setting: a single-center, retrospective study.

PURPOSE: To investigate the association between adherence to guideline-recommended risk-based postoperative nausea and vomiting (PONV) prophylaxis, the antiemetics used for PONV prophylaxis, and the incidence of PONV in patients who were underwent general anesthesia before and after 5-HT3 receptor antagonists became available. METHODS: Patients (≥ 20 years old) who were extubated after scheduled surgery and returned to general wards between January 2021 and February 2022 and between June 2022 and July 2023 were included. Risk factors included age < 50, female, motion sickness, nonsmoker, surgical factors, and postoperative opioid use. Two and three or more prophylaxis were recommended for patients with one or two and three or more risk factors, respectively. The primary outcome was the number of patients who received adequate prophylaxis, and the secondary outcomes were antiemetic agents used during anesthesia and the incidence of PONV on postoperative days 0 and 1. PONV was defined as documented PONV or rescue antiemetic administration. RESULTS: From January 2021 to February 2022 and from June 2022 to July 2023, 2342 and 2682 patients were included, respectively. Before ondansetron became available, more D2 receptor antagonists were used (p < 0.001), and after ondansetron became available, both ondansetron (p < 0.001) and propofol (p < 0.001) were given more frequently. Before and after ondansetron became available, the number of patients with adequate prophylaxis was 3.7% and 9.2%, respectively (p < 0.001), and the incidence of PONV on postoperative days 0 and 1 was 44.6% and 44.0%, respectively (p = 0.67). CONCLUSION: The availability of ondansetron increased the number of patients with adequate PONV prophylaxis, but did not decrease the incidence of PONV.

Palonosetron for prevention of delayed chemotherapy-induced nausea and vomiting in pediatric patients: a meta-analysis.

PURPOSE: Chemotherapy-induced nausea and vomiting (CINV) are common adverse events in patients undergoing emetogenic chemotherapy. Palonosetron, a second-generation 5-hydroxytryptamine-3 receptor antagonist (5-HT3 RA), has demonstrated non-inferiority to first-generation 5-HT3 RAs for CINV in pediatric patients. Although palonosetron has a long half-life and prolonged antiemetic action, its efficacy against delayed CINV in pediatric patients is not well understood. Therefore, this meta-analysis of randomized controlled trials (RCTs) aimed to evaluate the efficacy of palonosetron for delayed CINV in pediatric patients. METHODS: A literature search of MEDLINE/PubMed, Embase, Cochrane Library, and Web of Science databases was performed. A meta-analysis was performed using forest plots, and risk ratios (RRs) and 95% confidence intervals (CIs) were calculated. A funnel plot was constructed to explore publication bias. RESULTS: The literature search retrieved 842 records, of which 23 full-text articles were assessed, including six RCTs. Meta-analysis of four RCTs that reported on the complete response (CR: defined as no emesis and no rescue medication) rate for delayed CINV revealed that palonosetron was statistically superior to first-generation 5-HT3 RAs (RR = 1.21 [95% CI 1.09-1.35]; p < 0.01). Although the number of studies included was small, no publication bias was observed in the funnel plots. In addition, the CR rate for overall and acute CINV was also significantly higher for palonosetron (RR = 1.25 [95% CI 1.01-1.54]; p = 0.04 and RR = 1.06 [95% CI 1.01-1.12]; p = 0.03, respectively). CONCLUSION: Palonosetron is effective in the prophylaxis of delayed CINV in pediatric patients.

Isopropyl alcohol inhalation versus 5-HT3 antagonists for treatment of nausea: a meta-analysis of randomised controlled trials.

PURPOSE: Nausea is a common and unpleasant sensation for which current therapies such as serotonin (5-HT3) antagonists are often ineffective, while also conferring a risk of potential adverse events. Isopropyl alcohol (IPA) has been proposed as a treatment for nausea. We aimed to compare IPA with 5-HT3 antagonists for the treatment of nausea across all clinical settings. METHODS: MEDLINE, EMBASE, PubMed, CENTRAL and CINAHL were searched from inception to 17 July 2023 for randomised controlled trials (RCTs) comparing inhaled IPA and a 5-HT3 antagonist for treatment of nausea. Severity and duration of nausea, rescue antiemetic use, adverse events and patient satisfaction were the outcomes sought. Risk of bias (RoB) was assessed using Cochrane RoB 2. Random-effects model was used for meta-analysis. Combination of meta-analyses and narrative review was used to synthesise findings. The evidence was appraised using GRADE. RESULTS: From 1242 records, 4 RCTs were included with 382 participants. Participants receiving IPA had a significantly lower mean time to 50% reduction in nausea (MD - 20.06; 95% CI - 26.26, - 13.85). Nausea score reduction at 30 min was significantly greater in the IPA group (MD 21.47; 95% CI 15.47, 27.47). IPA led to significantly reduced requirement for rescue antiemetics (OR 0.60; 95% CI 0.37, 0.95; p = 0.03). IPA led to no significant difference in patient satisfaction when compared with a 5-HT3 antagonist. The overall GRADE assessment of evidence quality ranged from very low to low. CONCLUSION: IPA may provide rapid, effective relief of nausea when compared with 5-HT3 antagonists.

Italian guidelines for the management of irritable bowel syndrome Joint Consensus from the Italian Societies of: Gastroenterology and Endoscopy (SIGE), Neurogastroenterology and Motility (SINGEM), Hospital Gastroenterologists and Endoscopists (AIGO), Digestive Endoscopy (SIED), General Medicine (SIMG), Gastroenterology, Hepatology and Pediatric Nutrition (SIGENP) and Pediatrics (SIP)

The irritable bowel syndrome (IBS) is a chronic disorder of gut-brain interaction. IBS is still associated with areas of uncertainties, especially regarding the optimal diagnostic work-up and the more appropriate management. Experts from 7 Italian Societies conducted a Delphi consensus with literature summary and voting process on 27 statements. Recommendations and quality of evidence were evaluated using the grading of recommendations, assessment, development, and evaluation (GRADE) criteria. Consensus was defined as >80% agreement and reached for all statements. In terms of diagnosis, the consensus supports a positive diagnostic strategy with a symptom-based approach, including the psychological comorbidities assessment and the exclusion of alarm symptoms, together with the digital rectal examination, full blood count, C-reactive protein, serology for coeliac disease, and fecal calprotectin assessment. Colonoscopy should be recommended in patients with alarm features. Regarding treatment, the consensus strongly supports a dietary approach for patients with IBS, the use of soluble fiber, secretagogues, tricyclic antidepressants, psychologically directed therapies and, only in specific IBS subtypes, rifaximin. A conditional recommendation was achieved for probiotics, polyethylene glycol, antispasmodics, selective serotonin reuptake inhibitors and, only in specific IBS subtypes, 5-HT3 antagonists, 5-HT4 agonists, bile acid sequestrants

Inhibition of Spinal 5-HT3 Receptor and Spinal Dorsal Horn Neuronal Excitability Alleviates Hyperalgesia in a Rat Model of Parkinson's Disease.

Pain in Parkinson's disease (PD) is increasingly recognized as a major factor associated with poor life quality of PD patients. However, classic therapeutic drugs supplying dopamine have limited therapeutic effects on PD-related pain. This suggests that there is a mechanism outside the dopamine system that causes pain in PD. Our previous study demonstrated that 6-OHDA induced PD model manifested hyperalgesia to thermal and mechanical stimuli and decreased serotonin (5-hydroxytryptamine; 5-HT) in the spinal dorsal horn (SDH). Several 5-HT receptor subtypes have been confirmed to be associated with nociception in the spinal cord, such as 5-HT1A receptor, 5-HT1B receptor, 5-HT2 receptor, 5-HT3 receptor, and 5-HT7 receptor. Most research has shown that 5-HT1A receptor and 5-HT3 receptor play a key role in pain transmission in the spinal cord. We hypothesized that hyperalgesia of 6-OHDA rats may be related to increased excitability of SDH neurons, and functional change of 5-HT3 receptor may reverse the hyperalgesia of 6-OHDA lesioned rats and decrease cell excitability of SDH neurons. To test this hypothesis, we used whole-cell patch-clamp and pharmacological methods to evaluate the effect of 5-HT3 receptor and 5-HT1A receptor on the hyperalgesia of 6-OHDA rats. The results suggested that increased excitability in SDH neurons could be reversed by 5-HT3 receptor antagonist ondansetron (20 µmol/L) and palosetron (10 µmol/L), but not 5-HT3 receptor agonist m-CPBG (30 µmol/L) and SR 57,727 (10 µmol/L), 5-HT1A receptor agonist 8-OH DPAT (10 µmol/L) and eptapirone (10 µmol/L) and 5-HT1A receptor antagonist WAY-100635 (10 µmol/L) and p-MPPI (10 µmol/L). Intrathecal injection of ondansetron (0.1 mg/kg) but not m-CPBG (0.1 mg/kg), 8-OH DPAT (0.1 mg/kg), and WAY-100635 (0.1 mg/kg) significantly attenuated the mechanical hyperalgesia and thermal hyperalgesia in 6-OHDA lesioned rats. In conclusion, the present study suggests that inhibition of spinal 5-HT3 receptor and SDH neuronal excitability alleviates hyperalgesia in PD rats. Our study provides a novel mechanism or therapeutic strategy for pain in patients with PD.

Effects of adding a neurokinin-1 receptor antagonist to 5 mg olanzapine, a 5-hydroxytryptamine-3 receptor antagonist, and dexamethasone for preventing carboplatin-induced nausea and vomiting: a propensity score-matched analysis.

BACKGROUND: Olanzapine has been reported to be an effective antiemetic in patients receiving carboplatin-based chemotherapy. However, the efficacy of a neurokinin-1 receptor antagonist (NK1RA) added to olanzapine, a 5-hydroxytryptamine-3 receptor antagonist (5-HT3RA), and dexamethasone (DEX) has not been proven. This study aimed to assess the efficacy and safety of NK1RA, in combination with three-drug antiemetic regimens containing olanzapine, in preventing nausea and vomiting induced by carboplatin-based chemotherapy. METHODS: Data were pooled for 140 patients receiving carboplatin-based chemotherapy from three multicenter, prospective, single-arm, open-label phase II studies that evaluated the efficacy and safety of olanzapine for chemotherapy-induced nausea and vomiting. The propensity score of the co-administration of NK1RA was estimated for each patient using a logistic regression model that included age, sex, and carboplatin dose. We analyzed a total of 62 patients, who were treated without NK1RA (non-NK1RA group: 31 patients) and with NK1RA (NK1RA group: 31 patients). The patients were selected using propensity score matching. RESULTS: The complete response rate (without emetic episodes or with no administration of rescue medication) in the overall period (0-120 h post carboplatin administration) was 93.5% in the non-NK1RA group and 96.8% in the NK1RA group, with a difference of -3.2% (95% confidence interval, -18.7% to 10.9%; P = 1.000). In terms of safety, there was no significant difference between the groups in daytime sleepiness and concentration impairment, which are the most worrisome adverse events induced by olanzapine. CONCLUSIONS: The findings suggest that antiemetic regimens consisting of olanzapine, 5HT3RA, and DEX without NK1RA may be a treatment option for patients receiving carboplatin-based chemotherapy.

Study protocol for a double-blind, comparative, randomised Japanese trial of triplet standard antiemetic therapies with or without 5 mg olanzapine to prevent chemotherapy-induced nausea and vomiting for patients with breast cancer treated with an anthracycline/cyclophosphamide regimen (JTOP-B).

INTRODUCTION: Triple antiemetic therapy with neurokinin-1 receptor antagonist, 5-hydroxytryptamine type 3 receptor antagonist, and dexamethasone has been widely recommended for high emetogenic chemotherapeutic (HEC) agents and regimens, including anthracycline combined with cyclophosphamide (AC). The addition of olanzapine (OLZ) 5 mg or 10 mg to the recommended triple antiemetic therapy has demonstrated superiority in antiemetic efficacy compared with the standard triplet therapy for a cisplatin-based HEC regimen. Although OLZ plus the triple antiemetic treatment may also be effective for patients on an AC-based HEC regimen, no study has investigated its efficacy at a lower dose of 5 mg. METHODS AND ANALYSIS: To assess whether 5 mg OLZ, as compared with placebo, in combination with triple combination therapy, significantly improves nausea and vomiting, we are conducting a randomised, parallel-group controlled clinical trial with a total of 500 patients at 15 study centres in Japan. The primary outcome is the complete response rate, defined as no emetic episodes and no use of rescue medication during 120 hours after the initiation of chemotherapy. Treatment group comparison for the primary endpoint will be done by using the Cochran-Mantel-Haenszel test. ETHICS AND DISSEMINATION: The study was approved by the institutional review board of Juntendo University Hospital and relevant approval was obtained from all participating centres. All participants will be required to provide written informed consent. The trial results will be reported at conferences and in peer-reviewed journals. TRIAL REGISTRATION NUMBER: Japan Registry of Clinical Trials (jRCT) jRCT1031200134; protocol date: 30 July 2020, version: 1.3, approval: 25 August 2020.

Analgesic effects of a 5-HT3 receptor antagonist in an animal model of complex regional pain syndrome.

OBJECTIVE: Complex regional pain syndrome (CRPS) is caused by injuries from fracture after trauma and orthopaedic surgical procedures in the hind limbs. The symptoms of CRPS include warmth, pain, allodynia, and hyperalgesia. It is known that 5-hydroxytryptamine 3 (5-HT3) receptors contribute to hyperalgesia, but their role has not yet been fully elucidated. This study investigated the mechanism of pain relief when a 5-HT3 receptor antagonist was administered in a CRPS animal model. MATERIALS AND METHODS: To establish a CRPS animal model, 10-week-old Sprague-Dawley rats were used in the experiment. On the fourth week post tibial fracture surgery, we performed the von Frey test to measure mechanical allodynia. After performing behavioural tests, we collected blood and tissue samples after sacrificing the animals. Enzyme-linked immunosorbent assay and western blot were also performed. RESULTS: The experimental tibia fracture model-induced CRPS animals elicited increased 5-HT3 receptor expression, and the 5-HT transporter was decreased in the brain stem after 4 weeks of surgical intervention. Additionally, in CRPS-induced animals, both the concentration of substance P and the level of interleukin 6 were increased peripherally and centrally. Treatment with the 5-HT3 receptor antagonist, ramosetron, exerted an analgesic effect in the paw withdrawal test and was dependent on the attenuation of the 5-HT3 receptor population with inflammatory pain mediators. CONCLUSIONS: These data suggest that treatment with the 5-HT3 receptor antagonist, ramosetron, in experimental CRPS animal models alleviated pain-related behaviours and may be a new therapeutic option or potential therapeutic agent for patients with CRPS.

Structure-Based Design and Optimization of FPPQ, a Dual-Acting 5-HT3 and 5-HT6 Receptor Antagonist with Antipsychotic and Procognitive Properties.

In line with recent clinical trials demonstrating that ondansetron, a 5-HT3 receptor (5-HT3R) antagonist, ameliorates cognitive deficits of schizophrenia and the known procognitive effects of 5-HT6 receptor (5-HT6R) antagonists, we applied the hybridization strategy to design dual-acting 5-HT3/5-HT6R antagonists. We identified the first-in-class compound FPPQ, which behaves as a 5-HT3R antagonist and a neutral antagonist 5-HT6R of the Gs pathway. FPPQ shows selectivity over 87 targets and decent brain penetration. Likewise, FPPQ inhibits phencyclidine (PCP)-induced hyperactivity and displays procognitive properties in the novel object recognition task. In contrast to FPPQ, neither 5-HT6R inverse agonist SB399885 nor neutral 5-HT6R antagonist CPPQ reversed (PCP)-induced hyperactivity. Thus, combination of 5-HT3R antagonism and 5-HT6R antagonism, exemplified by FPPQ, contributes to alleviating the positive-like symptoms. Present findings reveal critical structural features useful in a rational polypharmacological approach to target 5-HT3/5-HT6 receptors and encourage further studies on dual-acting 5-HT3/5-HT6R antagonists for the treatment of psychiatric disorders.

Identification and molecular study on the interaction of Schisandrin C with human 5-HT3A receptor.

Schisandrin C (Sch C) is one of the main components of Schisandra chinensis (Schisandra). Since the olden times, Schisandra has been used as a traditional herbal medicine in Asia. Recent studies have shown that Schisandra is effective against irritable bowel syndrome (IBS) in an animal model and affects IBS through the 5-HT3A pathway in the IBS rat model. However, there lacks fundamental research on the interaction of specific components of Schisandra with the 5-HT3A receptor for the treatment of IBS. We hypothesized that a component of Schisandra binds to the 5-HT3A receptor and identified Sch C via a screening work using two electrode-voltage clamps (TEVC). Thus, we aimed to elucidate the neuropharmacological actions between Sch C and the 5-HT3A receptor at molecular and cellular levels. Co-treatment of Sch C with 5-HT inhibited I5-HT in a reversible, concentrate-dependent, like-competition, and voltage-independent manner, and IC50 values of Sch C. Besides, the main binding positions of Sch C were identified through 3D modeling and point mutation were V225A and V288Y on 5-HT3A receptor. Thus, we suggest the potential of Sch C in treating IBS in a manner that suppresses excessive neuronal serotonin signaling in the synapse of sensory neurons and enterochromaffin (EC) cells. In conclusion, the results demonstrate the mechanism of interaction between Sch C and 5-HT3A receptor and reveal Sch C as a novel antagonist.

Effectiveness of palonosetron versus granisetron in preventing chemotherapy-induced nausea and vomiting: a systematic review and meta-analysis.

PURPOSE: Chemotherapy-induced nausea and vomiting (CINV) commonly occurs after chemotherapy, adversely affecting patients' quality of life. Recently, studies have shown inconsistent antiemetic effects of two common 5-hydroxytryptamine 3 receptor antagonists, namely, palonosetron and granisetron. Therefore, we conducted a meta-analysis to evaluate the effectiveness of palonosetron versus granisetron in preventing CINV. METHODS: Relevant studies were obtained from PubMed, Embase, and Cochrane databases. The primary outcome was the complete response (CR) rate. Secondary outcomes were headache and constipation events. RESULTS: In total, 12 randomized controlled trials and five retrospective studies were reviewed. Palonosetron was consistently statistically superior to granisetron in all phases in terms of the CR rate (acute phases: odds ratio [OR] = 1.28, 95% confidence interval [CI] = 1.06-1.54; delayed phases: OR = 1.38, 95% CI = 1.13-1.69; and overall phases: OR = 1.37, 95% CI = 1.17-1.60). Moreover, a non-significant difference was found between the two groups in terms of the headache event, but the occurrence of the constipation event was lower in the granisetron group than in the palonosetron group. CONCLUSION: Palonosetron showed a higher protective efficacy in all phases of CINV prevention, especially in delayed phases, and no relatively severe adverse effects were observed.

Prevention of chemotherapy-induced nausea and vomiting in the real-world setting in Spain.

PURPOSE: Proper monitoring and management of chemotherapy-induced nausea and vomiting (CINV) with antiemetics is crucial for cancer patients. This study aimed to evaluate the use of antiemetics for the treatment of highly emetogenic chemotherapy (HEC) including carboplatin in the real-world setting in Spain. METHODS: A representative panel of cancer specialists was asked to collect information about the antiemetic treatments provided to patients receiving chemotherapy. Records formed part of the Global Oncology Monitor© database (Ipsos Healthcare, London, UK). Chemotherapy data were extrapolated using Ipsos Healthcare's projection methodology. RESULTS: A total of 73 experts were finally included. Data from 9519 patients, estimated to be representative of 202,084 patients, were collected. HEC (and carboplatin-based chemotherapy) was administered to 73,118 (36%) patients, cisplatin-based therapy being the most frequent treatment (n = 34,649, 47.38%). Neurokinin-1 receptor antagonists (NK1RAs) alone or in combination were used as prophylaxis for CINV in 14,762 (20%) patients, while the combination of NK1RA with 5-hydroxytryptamine-3 receptor antagonist (5-HT3RAs) and dexamethasone as recommended by the international guidelines was used in 5849 (8%) patients only. No antiemetic prophylaxis was administered to 8.46% of the patients receiving HEC (n = 6189). Physicians classified cisplatin-, anthracycline-cyclophosphamide (AC-), and carboplatin-based regimens as HEC in 63%, 22% and 4% of the cases, respectively. CONCLUSIONS: The use of NK1RA-containing regimens for CINV prevention in patients treated with HEC was less than expected, suggesting poor adherence to international antiemetic guidelines.

Anterior resection syndrome: a randomized clinical trial of a 5-HT3 receptor antagonist (ramosetron) in male patients with rectal cancer.

BACKGROUND: No effective treatment exists for anterior resection syndrome (ARS) following sphincter-saving surgery for rectal cancer. This RCT assessed the safety and efficacy of a 5-HT3 receptor antagonist, ramosetron, for ARS. METHODS: A single-centre, randomized, controlled, open-label, parallel group trial was conducted. Male patients with ARS 1 month after rectal cancer surgery or ileostomy reversal were enrolled and randomly assigned (1 : 1) to 5 µg of ramosetron (Irribow®) daily or conservative treatment for 4 weeks. Low ARS (LARS) score was calculated after randomization and 4 weeks after treatment. The study was designed as a superiority test with a primary endpoint of the proportion of patients with major LARS between the groups. Primary outcome analysis was based on the modified intention-to-treat population. Safety was assessed by monitoring adverse events during the study. RESULTS: : A total of 100 patients were randomized to the ramosetron (49 patients) or conservative treatment group (51 patients). Two patients were excluded, and 48 and 50 patients were analysed in the ramosetron and control groups, respectively. The proportion of major LARS after 4 weeks was 58 per cent (28 of 48 patients) in the ramosetron group versus 82 per cent (41 of 50 patients) in the control group, with a difference of 23.7 per cent (95 per cent c.i. 5.58 to 39.98, P = 0.011). There were minor adverse events in five patients, which were hard stool, frequent stool or anal pain. These were not different between the two groups. There were no serious adverse events. CONCLUSION: : Ramosetron could be safe and feasible for male patients with ARS. TRIAL REGISTRATION NUMBER: NCT02869984 (http://www.clinicaltrials.gov).

The trichothecene neosolaniol stimulates an emetic response through neuropeptide Y2 and serotonin 3 receptors in mink.

Type A trichothecene neosolaniol (NEO) is considered a potential risk to human and animal health by the European Food Safety Authority (EFSA). To date, available data do not allow making conclusions about the toxicological properties of this toxin. Trichothecenes have been previously demonstrated to induce emetic responses in mink, and this response has been associated with neurotransmitter peptide YY (PYY) and serotonin (5-hydroxytryptamine, 5-HT). The goal of this study was to compare emetic effects of NEO administered by intraperitoneal and oral routes and relate these effects to PYY and 5-HT. The effective doses resulting in emetic events in 50% of the animals following intraperitoneal and oral exposure to NEO were 0.4 and 0.09 mg/kg bw, respectively. This emetic response corresponded to elevated PYY and 5-HT levels. Blocking the neuropeptide Y2 receptor diminished emesis induction by PYY and NEO. The 5-HT3 receptor inhibitor granisetron completely restrained the induction of emesis by 5-HT and NEO. To summarize, our findings demonstrate that PYY and 5-HT play important roles in the NEO-induced emetic response.

Memantine in neurological disorders - schizophrenia and depression.

Memantine is used in Alzheimer's disease treatment as a non-competitive modern-affinity strong voltage-dependent N-methyl-D-aspartate receptor antagonist. The fundamental role of these receptors is to bind glutamate: the main excitatory neurotransmitter in the brain, believed to play a crucial role in neuronal plasticity and learning mechanisms. Glutamate transmission plays an important role in all internal CNS structures and maintains the physiological state of the brain. Excessive glutamate transmission can lead to enlarged calcium ion current which may cause neurotoxicity; however, insufficient transmission can drastically alter the information flow in neurons and the brain, potentially causing schizophrenia-like symptoms by replacing lost information with completely new stimuli. Hence, it is possible that the modulation of NMDA activity may give rise to pathophysiological states. Available literature and clinical trials indicate that memantine is well tolerated by patients, with very few and light side effects. There is a belief that memantine may also benefit other conditions such as schizophrenia and depression.

5-HT3 receptor antagonism a potential therapeutic approach for the treatment of depression and other disorders.

BACKGROUND: Depression or Major depressive disorder (MDD) is a prolonged condition of sadness. MDD is the most common mental disorder that affects more than 264 million people worldwide. According to the monoamine hypothesis, serotonin (5-hydroxy tryptamine, 5-HT), dopamine (DA) and norepinephrine (NE) are the major neurotransmitters (NTs) involved in depression. METHODS: The methodology adopted for writing this review article is essentially based on the secondary literature search through a systematic literature review. This review mainly focussed on the role of 5-HT3 receptor antagonists (5-HT3RA) in depression and comorbid disorders like anxiety. RESULTS: Out of three major NTs mentioned above, serotonin has a predominant role in the pathophysiology of depression. The serotonin type-3 receptors (5-HT3R) are well renowned to be expressed in the central nervous system (CNS) in regions which have significance in the vomiting reflex, perception of pain, the reward system, cognition, depression and anxiety control. 5-HT3R are the receptors of serotonergic family that belong to ligand-gated ion channel. 5-HT3RA inhibit the binding of serotonin to postsynaptic 5-HT3R and increases its availability to other receptors like 5- HT1A, 1B and 1D as well as 5-HT2 receptors and produces anti-depressant-like effect. 5-HT3RA also have an important role in mood and stress disorders. Some of the studies have shown the effectiveness of these agents in stress disorder. CONCLUSION: The present article focussed on the role of 5-HT3R and their antagonists in the treatment of depression and anxiety. Further studies are warranted to prove their efficacy with respect to other standard anti-depressants.

Chemotherapy-Induced Nausea and Vomiting: Pathogenesis, Recommendations, and New Trends.

The significant physical and emotional effects of chemotherapy-induced nausea and vomiting (CINV) are experienced by cancer patients. Severe symptoms decrease the patient's quality of life and potentially deters further treatment. The five main forms of CINV (i.e., acute, delayed, anticipatory, breakthrough, and refractory) require different treatment regimens, which often include 5-HT3 receptor antagonists, NK1 receptor antagonists, and corticosteroids. Despite a significant amount of research and development of antiemetic agents, management of CINV remains a great challenge with many needs waiting to be adequately addressed, such as controlling non-acute CINV, developing appropriate CINV treatment protocols for multiple-day chemotherapy patients, and providing options for those prone to CINV despite treatment. Further research is required to optimize CINV management for these patients.

5HT3 RA plus dexamethasone plus aprepitant for controlling delayed chemotherapy-induced nausea and vomiting in colorectal cancer.

Delayed chemotherapy-induced nausea and vomiting (CINV) is not well controlled in colorectal cancer (CRC) patients undergoing oxaliplatin (L-OHP)-based chemotherapy. Whether neurokinin-1 receptor antagonist addition to a first-generation 5HT3 antagonist (1st 5-HT3 RA) and dexamethasone (DEX) is beneficial to these patients remains controversial. Furthermore, whether palonosetron (PALO) or aprepitant (APR) is more effective in controlling delayed CINV is unclear. We, therefore, investigated whether PALO+DEX or 1st 5-HT3 RA+DEX+APR was more effective in controlling delayed CINV, and the risk factors for delayed CINV, in CRC patients undergoing L-OHP-based chemotherapy. Data were pooled from two prospective observational Japanese studies and a phase III trial to compare CINV incidence between the PALO + DEX (PALO) and 5-HT3 RA+DEX+APR (APR) groups by propensity score-matched analysis. CINV risk factors were identified using logistic regression models. The CINV incidence was higher in the PALO group than in the APR group. Logistic regression analysis revealed alcohol consumption, motion sickness, and the PALO+DEX regimen as independent risk factors for delayed nausea, and female sex and the PALO+DEX regimen as those for delayed vomiting. Compared with prophylactic PALO + DEX, 1st 5-HT3 RA+DEX+APR was more effective in controlling delayed CINV. Thus, CRC patients receiving L-OHP-based chemotherapy should be treated with three antiemetics, including APR.

Selective blockade of the 5-HT3 receptor acutely alleviates dyskinesia and psychosis in the parkinsonian marmoset.

In Parkinson's disease (PD), management of L-3,4-dihydroxyphenylalanine (l-DOPA)-related complications, such as l-DOPA induced dyskinesia and psychosis, remains inadequate, which poses a significant burden on the quality of life of patients. We have shown, in the hemi-parkinsonian rat model of PD, that the selective serotonin type 3 (5-HT3) receptor antagonists ondansetron and granisetron decreased the severity of established dyskinesia, and ondansetron even attenuated the development of dyskinesia. Here, we seek to confirm these favourable data on dyskinesia and to explore the effect of ondansetron on the severity of psychosis-like behaviours (PLBs) in the gold standard model of PD, the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned non-human primate. We first determined the pharmacokinetic profile of ondansetron in the marmoset. Subsequently, six MPTP-lesioned marmosets were administered l-DOPA chronically until they exhibited stable and reproducible dyskinesia and PLBs upon each administration of l-DOPA. On behavioural assessment days, ondansetron (0.01, 0.1 and 1 mg/kg) or vehicle was administered in conjunction with l-DOPA, and the severity of dyskinesia, PLBs and parkinsonism was evaluated. Ondansetron 0.1 mg/kg alleviated global dyskinesia severity by 73% (P < 0.0001) and decreased duration of on-time with disabling dyskinesia by 88% (P = 0.0491). Ondansetron 0.1 mg/kg reduced the severity of global PLBs by 80% (P < 0.0001) and suppressed on-time with disabling PLBs (P = 0.0213). Ondansetron enhanced the anti-parkinsonian action of l-DOPA, reducing global parkinsonism by 53% compared to l-DOPA (P = 0.0004). These results suggest that selective blockade of the 5-HT3 receptor with ondansetron may be an effective approach to alleviate l-DOPA-related complications.