Neurokinin-1 Receptor Research Articles

A phase II study of ME2136 (Asenapine Maleate) plus standard antiemetic therapy for patients, including diabetic patients, receiving cisplatin-based chemotherapy.

Olanzapine combined with the neurokinin-1 receptor antagonist, palonosetron and dexamethasone is the standard treatment for chemotherapy-induced nausea and vomiting (CINV) due to highly emetogenic chemotherapy (HEC). However, the use of olanzapine poses challenges in patients with diabetes mellitus (DM) due to the potential risk of hyperglycemia. ME2136, antipsychotic similar to olanzapine, is associated with a lower risk of hyperglycemia. This study investigated the antiemetic efficacy and safety of ME2136 for HEC. This single-arm phase 2 study examined the safety and efficacy of ME2136 5mg for 4days in combination with triplet-combination antiemetic therapy. Two cohorts were established for the safety assessment: DM and non-DM. Eligible patients had malignant tumors and were receiving cisplatin-based chemotherapy for the first time. The primary endpoint was the complete response (CR) rate, defined as the percentage of patients without vomiting and not requiring rescue medications in the delayed phase (24-120h). Between December 2020 and January 2022, 40 patients were enrolled, with 20 in each cohort. All patients were included in the safety analysis and 35 in the efficacy analysis. The CR rate in the delayed phase was 71.4% [60% CI 63.1-78.6%] for all patients, 66.7% in the DM cohort, and 76.5% in the non-DM cohort. No treatment-related adverse events ≥ grade 3, including hyperglycemia, were reported. ME2136, when combined with standard triplet-combination antiemetic therapy, is expected to exert similar antiemetic effects to the standard treatment for CINV due to HEC. Currently, ME2136-02 trial is underway to examine the safety and efficacy of triplet-combination antiemetic therapy and a 5-day treatment with ME2136. This study was registered with the Japan Registry of Clinical Trials (jRCT2041200071) on 10 December 2020. Clinical trial registration: This study was registered with the Japan Registry of Clinical Trials (jRCT2041200071) on 10 December 2020.

What is new on peri- and postmenopause?

Menopause is an increasingly discussed topic in recent years. More women are demanding consultancy and help from their doctors via different channels, be it online or in menopause centers.The term genitourinary syndrome of menopause (GSM) comprises vaginal and urological symptoms such as mucosal dryness, itching and burning, dysuria or bleeding and pain during sexual intercourse. GSM can strongly affect quality of life, is common if estrogen deficiency has lasted for 3 months and can be treated locally with very low doses of the weak estrogen estriol."Not feeling like myself anymore" - symptomatic perimenopause may present with sleep disturbances, mastalgia, mood swings, palpitations, panic attacks, but also entail joint pain, vertigo, headache, and brain fog - even years before menopause and in the presence of still adequate estrogen levels. In an online study, 20% of women in the menopausal transition reported symptoms which they could not explain, and which may cause fears of serious illness. This can lead to extensive medical work-ups if the possibility of perimenopause as the cause is disregarded.(Peri-)menopausal complaints last much longer than previously thought: The Study of women's health across the nation (SWAN) reported longer duration of vasomotor symptoms (median: 11,8 years) in women who were already affected in early perimenopause, while those in whom VMS started only after menopause experienced a shorter duration of symptoms (median: 3,4 years).Female hormones protect women from fatty streaks and hypertension, but menopausal hormone therapy (MHT) has positive effects only if started in the first decade after menopause. The interaction with stress, aging and lifestyle factors is complex.For the treatment of VMS, German and international guidelines list both drug and non-drug or non-prescription options, although there is no clear data on their effectiveness.Fezolinetant, a Neurokinin-3 receptor antagonist, is now available in Germany for the treatment of vasomotor symptoms in postmenopausal women with contraindications or aversion against steroid hormones. It modulates the thermoregulation center in the hypothalamus by blocking the KNDy-neurons. Studies on Elinzanetant, another representative of this class of drugs, are still ongoing.

Incidence of post-operative nausea and vomiting after endoscopic bariatric and metabolic therapy procedures and the role of neurokinin-1 receptor antagonists: a retrospective cohort study.

Both the transoral gastric reduction (TORe) and endoscopic sleeve gastroplasty (ESG) procedures are novel endoscopic bariatric and metabolic therapies (EBMT). Our practice has an aggressive approach to prophylaxis of postoperative nausea and vomiting (PONV) for EBMT cases, but there is divergence of practice regarding use of prophylactic neurokinin-1 receptor (NK-1) antagonists (aprepitant, fosaprepitant). Herein, we determined the incidence of PONV and its potential association with NK-1 antagonist administration following EBMT. We identified and reviewed medical records of patients who underwent EBMT between 2018 and 2023. Patients were divided into those administered or not administered an NK-1 antagonist. We analyzed rates of PONV, which was defined as rescue antiemetics during anesthesia recovery. A propensity score was calculated, and outcomes were assessed using generalized estimating equations with inverse probability of treatment weighting (IPTW). We identified 404 patients undergoing EBMT (256 [63%] TORe, 148 [37%] ESG), and of these 253 patients developed PONV, (62.6% [95% CI: 57.9% to 67.3%]). NK-1 antagonists were administered to 119 (29.5%) patients. PONV was experienced by 42 (35%) and 211 (74%) of patients who were or were not administered an NK-1 antagonist, respectively (IPTW OR = 0.18, [95%CI: 0.10 to 0.31], P < 0.001). EBMT has a high incidence of PONV during anesthesia recovery. Administration of a NK-1 antagonist as part of a multiagent PONV prophylaxis regimen dramatically reduces risk for this common adverse event.

Fosaprepitant improves cyclophosphamide-induced bladder damage by alleviating inflammatory response in mice

Inhibition of inflammatory process is a key therapeutic target for the treatment of interstitial cystitis (IC). Recent reports indicate that neurokinin 1 receptor (NK1R) antagonists have beneficial roles in inflammatory-based diseases. Herein, we investigate the protective effects of fosaprepitant (FOS), a NK1R antagonist, in cyclophosphamide (CP)-induced cystitis. The cystitis model was established multiple CP (80 mg/kg; i.p.) injection one day apart, and mice were treated with FOS (20 and 60 mg/kg/day; i.p.) for seven consecutive days. Detrusor contractility, vesical vascular permeability, myeloperoxidase (MPO) activity and protein expression levels of the TLR4 pathway were evaluated in mice bladder. Carbachol and electric field stimulation-evoked contractions of detrusor strips were significantly increased in CP-treated mice, which was significantly attenuated by FOS (60 mg/kg/day) treatment (p<0.001, p<0.05). Notably, vesical vascular permeability was markedly impaired in CP-induced cystitis, that was restored by FOS (60 mg/kg/day) treatment (p<0.01). MPO activity was significantly increased in cystitis group whereas FOS (20 and 60 mg/kg/day) treatment remarkably suppressed MPO activity in bladder tissue (p<0.001). Although TLR4 expression increased with cystitis, MyD88 and p-NFκBSer536/total NFκB did not change, FOS (20 and 60 mg/kg/day) treatment caused a dramatic decrease in TLR4 expression (p<0.001), indicating the anti-inflammatory effect of FOS. In conclusion, FOS improved detrusor overactivity and inflammatory response by inhibiting MPO activity and TLR4 expression, resulting in functional and histological recovery in CP-induced cystitis.

7985 Insights into the Menopausal Transition: A Comparative Analysis of Hypothalamic Reproductive Aging in Women and a Mouse Model of Menopause

Abstract Disclosure: J.C. Bloom: None. S.A. Pereira: None. E. Torres Jimenez: None. D.C. Page: None. V.M. Navarro: None. Menopause onset is the major determinant of reproductive lifespan in women and is characterized by the decline in estrogen production from the ovary. While much of our current understanding of the menopause transition in humans comes from a series of observational longitudinal studies initiated in the 1980s and 1990s, the mechanisms by which reproductive aging impacts healthy brain aging remains a profoundly under-studied aspect of women’s health. The hypothalamus, a hub of homeostatic and temperature regulation, is highly sensitive to changes in sex steroid levels. Recently, activation of the neurokinin 3 receptor (NK3R) by neurokinin B (NKB) has been linked to the onset of vasomotor symptoms (VMS) during menopausal transition. NKB is secreted by hypothalamic Kisspeptin, NKB, Dynorphin (KNDy) neurons in response to decreasing estradiol levels. Here, we present a comparative study of the expression trajectories of the KNDy genes (KISS1, TAC3, PDYN, respectively) and NK3R (TACR3) in hypothalamic samples of humans across menopause and a mouse model of peri- and post-menopause (short- and long-term ovariectomy (OVX), respectively). RNA-sequencing data of human and mouse hypothalamic samples revealed a high correlation in the expression profile of the KNDy/NK3R genes between both species. Further investigation has revealed a highly conserved pool of genes in human and mouse hypothalami that correlate with TACR3 upon decline of circulating sex steroids. Thus, by examining conserved gene expression patterns across this critical reproductive period, we have been able to identify novel candidate targets involved in menopausal transition which may serve to better elucidate the biology of menopause-associated conditions affecting the brain, such as VMS and cognitive decline. Presentation: 6/2/2024

7985 Insights into the Menopausal Transition: A Comparative Analysis of Hypothalamic Reproductive Aging in Women and a Mouse Model of Menopause

Abstract Disclosure: J.C. Bloom: None. S.A. Pereira: None. E. Torres Jimenez: None. D.C. Page: None. V.M. Navarro: None. Menopause onset is the major determinant of reproductive lifespan in women and is characterized by the decline in estrogen production from the ovary. While much of our current understanding of the menopause transition in humans comes from a series of observational longitudinal studies initiated in the 1980s and 1990s, the mechanisms by which reproductive aging impacts healthy brain aging remains a profoundly under-studied aspect of women’s health. The hypothalamus, a hub of homeostatic and temperature regulation, is highly sensitive to changes in sex steroid levels. Recently, activation of the neurokinin 3 receptor (NK3R) by neurokinin B (NKB) has been linked to the onset of vasomotor symptoms (VMS) during menopausal transition. NKB is secreted by hypothalamic Kisspeptin, NKB, Dynorphin (KNDy) neurons in response to decreasing estradiol levels. Here, we present a comparative study of the expression trajectories of the KNDy genes (KISS1, TAC3, PDYN, respectively) and NK3R (TACR3) in hypothalamic samples of humans across menopause and a mouse model of peri- and post-menopause (short- and long-term ovariectomy (OVX), respectively). RNA-sequencing data of human and mouse hypothalamic samples revealed a high correlation in the expression profile of the KNDy/NK3R genes between both species. Further investigation has revealed a highly conserved pool of genes in human and mouse hypothalami that correlate with TACR3 upon decline of circulating sex steroids. Thus, by examining conserved gene expression patterns across this critical reproductive period, we have been able to identify novel candidate targets involved in menopausal transition which may serve to better elucidate the biology of menopause-associated conditions affecting the brain, such as VMS and cognitive decline. Presentation: 6/2/2024

Target-based discovery of antagonists of the tick (Rhipicephalus microplus) kinin receptor identifies small molecules that inhibit midgut contractions.

A GPCR (G protein-coupled receptor) target-based approach was applied to identify antagonists of the arthropod-specific tick kinin receptor. These small molecules were expected to reproduce the detrimental phenotypic effects that had been observed in Rhipicephalus microplus females when the kinin receptor was silenced by RNA interference. Rhipicephalus microplus, the southern cattle tick, cattle fever tick, or Asian blue tick, is the vector of pathogenic microorganisms causing the deadly bovine babesiosis and anaplasmosis. The widespread resistance to acaricides in tick populations worldwide emphasizes that exploring novel targets for effective tick control is imperative. Fifty-three structural analogs of previously identified tick kinin antagonists were screened in a 'dual-addition' calcium fluorescence assay using a CHO-K1 cell line expressing the tick kinin receptor. Seven molecules were validated as non-cytotoxic antagonists, four of which were partial (SACC-0428764, SACC-0428780, SACC-0428800, and SACC-0428803), and three were full antagonists (SACC-0428799, SACC-0428801, and SACC-0428815). Four of these antagonists (SACC-0428764, SACC-0428780, SACC-0428799, and SACC-0428815) also inhibited the tick midgut contractions induced by the myotropic kinin agonist analog 1728, verifying their antagonistic bioactivity. The small molecules were tested on recombinant human neurokinin (NK) receptors, the one most similar to the invertebrate kinin receptors. Most molecules were inhibitors of the NK1 receptor, except SACC-0412066, a previously identified tick kinin receptor antagonist, which inhibited the NK1 receptor only at the highest concentration tested (25 μm). None of the molecules inhibited the NK3 human receptor. Molecules identified through this approach could be useful probes for studying the tick kinin signaling system and midgut physiology. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Endomorphin-2 (Endo2) and substance P (SubP) co-application attenuates SubP-induced excitation and alters frequency plasticity in neonatal rat in vitro preparations

Substance P (SubP) and endomorphin-2 (Endo2) are co-localized presynaptically in vesicles of neurons adjacent to inspiratory rhythm-generating pre-Botzinger Complex (preBotC) neurons but the effects of co-released SubP and Endo2 on respiratory motor control are not known. To address this question, SubP alone or a combination of SubP and Endo2 (SubP/Endo2) were bath-applied in a sustained (15-min) or intermittent (5-min application, 5-min washout, x3) pattern at 10–100 nM to neonatal rat brainstem-spinal cord preparations. During neuropeptide application, SubP/Endo2 co-applications generally attenuated SubP-induced increases in burst frequency and decreases in burst amplitude. With respect to frequency plasticity (long-lasting increase in burst frequency 60 min post-neuropeptide application), SubP-induced frequency plasticity was increased with sustained SubP/Endo2 co-applications at 20 and 100 nM. Intermittent SubP/Endo2 co-applications tended to decrease the level of frequency plasticity induced by intermittent SubP alone applications. SubP/Endo2 co-applications revealed potentially new functions for neurokinin-1 (NK1R) and mu-opioid (MOR) receptors on respiratory rhythm-generating medullary neurons.

Comparative effectiveness of netupitant-palonosetron plus dexamethasone versus aprepitant-based regimens in mitigating chemotherapy-induced nausea and vomiting: a meta-analysis of randomized controlled trials.

Despite guidelines for managing chemotherapy-induced nausea and vomiting (CINV), there remains a need to clarify the optimal use of neurokinin-1 (NK1) receptor antagonists. Comparing the effectiveness of NEPA (netupitant-palonosetron) plus dexamethasone with other NK1 antagonist-based regimens combined with a 5HT3 receptor antagonist and dexamethasone is crucial for informed decision-making and improving patient outcomes. We conducted a systematic review of the literature to assess randomized controlled trials (RCTs) comparing the efficacy, safety, and cost-effectiveness of NEPA plus dexamethasone and other NK1 antagonist-based regimens combined with a 5HT3 receptor antagonist and dexamethasone. PubMed, Embase, and the Cochrane Library databases were systematically searched, with the latest update performed in December 2023. Data on patient demographics, chemotherapy regimen characteristics, and outcomes were extracted for meta-analysis using a random-effects model. Seven RCTs were analyzed. NEPA plus dexamethasone showed superior efficacy in achieving complete response in the overall (risk ratio [RR], 1.15; 95% CI, 1.02--1.30) and delayed phases (RR, 1.20; 95% CI, 1.03-1.41) of chemotherapy. It was more effective in controlling nausea (overall phase RR, 1.20; 95% CI, 1.05-1.36; delayed phase RR, 1.21; 95% CI, 1.05-1.40) and reducing rescue therapy use (overall phase RR, 1.45; 95% CI, 1.07-1.95; delayed phase RR, 1.75; 95% CI, 1.10-2.78). Adverse event rates were comparable (RR, 1.03; 95% CI, 0.96-1.10). Subgroup analysis indicated NEPA's particular efficacy in patients receiving moderately emetogenic chemotherapy (RR, 1.31; 95% CI, 1.07-1.60). NEPA plus dexamethasone regimens exhibit superior efficacy in preventing CINV, supporting their preferential inclusion in prophylactic treatment protocols. Its effective symptom control, safety profile, and cost-effectiveness endorse NEPA-based regimens as a beneficial option in CINV management.

Association of genetic variants in CYP3A5, DRD2 and NK1R with opioid overdose

In 2023, 3651 Ohioans died because of an opioid overdose. Of those opioid overdoses, 3579 (98%) of which were attributed to fentanyl. We evaluated the association between 180 candidate single nucleotide polymorphisms (SNPs) and self-reported, nonfatal opioid overdose history from a prospective sample of 1301 adult patients (≥18 years of age) seen in three urban emergency departments in Ohio. Candidate SNPs included 120 related to the dopamine reward pathway and 60 related to pharmacokinetics. Of the 821 patients who reported having been exposed to opioids in their lifetime, 95 (11.6%) also reported having experienced an opioid-related overdose. Logistic regression, adjusting for age and biologic sex, was used to characterize the association between each SNP and opioid overdose, correcting for multiple comparisons. Three SNPs, located in three different genes were associated with opioid overdose: increased odds with CYP3A5 (rs776746) and DRD2 (rs4436578), and decreased odds with NKIR (rs6715729). Homozygotic CYP3A5 (rs776746) had the highest adjusted odds ratio (OR) of 6.96 (95% CI [2.45, 29.23]) and homozygotic NK1R (rs6715729) had the lowest OR of 0.28 (95% CI [0.14, 0.54). Given that CYP3A5 (rs776746) has been associated with increased plasma concentrations of fentanyl, rs776746 could potentially be utilized as a prognostic risk indicator for the potential of an opioid overdose. NK1R regulates the expression of the neurokinin-1 receptor, a regulator of respiration and NK1R (rs6715729) represents a novel genetic marker for a decreased risk of opioid overdose risk.

Defining the clinical benefits of adding a neurokinin-1 receptor antagonist to control chemotherapy-induced nausea and vomiting in moderately emetogenic chemotherapy: a systematic review and meta-analysis of the clinical practice guidelines for antiemesis 2023 from the Japan society of clinical oncology.

Chemotherapy-induced nausea and vomiting (CINV) commonly affects patient quality of life and the overall effectiveness of chemotherapy. This study aimed to evaluate whether adding neurokinin-1 receptor antagonists (NK1RAs) to 5-hydroxytryptamine-3 receptor antagonists (5-HT3RAs) and corticosteroids provides clinically meaningful benefits in preventing CINV in patients receiving moderately emetogenic chemotherapy (MEC). We conducted a systematic review of PubMed, Cochrane Library, and Ichushi-Web to identify clinical studies evaluating NK1RAs combined with 5-HT3RAs and dexamethasone for managing CINV in MEC. The endpoints were complete response (CR), complete control (CC), total control (TC), adverse events, and costs. The data were analyzed using a random effects model. From 142 articles identified, 15 randomized controlled trials (RCTs), involving 4,405 patients, were included in the meta-analysis. Approximately 60% of the patients received carboplatin (CBDCA)-based chemotherapy. The meta-analysis showed that triplet antiemetic prophylaxis with NK1RA was significantly more effective for achieving CR than doublet prophylaxis in each phase. Regarding CC, the triplet antiemetic prophylaxis was significantly more effective than the doublet in the overall (risk difference [RD]: 0.11, 95% confidence interval [CI]: 0.06-0.17) and delayed (RD: 0.08, 95% CI: 0.02-0.13) phases. For TC, no significant differences were observed in any phase. Adding NK1RA did not cause adverse events. Adding NK1RA to CBDCA-based chemotherapy has shown clinical benefits. However, the clinical benefits of NK1RA-containing regimens for overall MEC have not yet been established and require RCTs that exclusively evaluate MEC regimens other than CBDCA-based chemotherapy.

Safety of a short-term infusion of fosnetupitant in patients with gastrointestinal and breast cancer: a prospective study.

Fosnetupitant, a neurokinin-1 receptor antagonist, is used to prevent chemotherapy-induced nausea and vomiting (CINV)in patients undergoing highly emetogenic chemotherapy (HEC) or moderately emetogenic chemotherapy (MEC). Previous phase III trials demonstrated the non-inferiority of its 30-minute infusion to fosaprepitant in efficacy and a favorable safety profile. This was a single-arm, phase II study to investigate the safety of a 15-minute infusion of fosnetupitant in patients with gastrointestinal and breast cancer. Patients who had received their dose of fosnetupitant in a 30-minute infusion without developing an allergic reaction were eligible and received their next fosnetupitant dose for 15 minutes. The primary endpoint was the incidence of an allergic reaction during the first 15-minutes infusion, and the secondary endpoints were the incidence of injection site reaction (ISR), the incidence of a grade ≥ 3 treatment-related adverse event (TRAE) with fosnetupitant, and complete response (CR) rate. The study period was from February 17, 2023 to June 20, 2023. In an exploratory analysis, medical records from the end of the study period to December 31, 2023 were retrospectively evaluated to assess the time-saving effect and safety of the short-term infusion of fosnetupitant. Fifty-six patients with gastrointestinal and 14 patients with breast cancer were enrolled, one of whom with breast cancer did not receive study treatment at her own request. No allergic reactions occurred during the 15-minutes infusion. Furthermore, there were no allergic reactions across all 280 short-term injections (Table 1). Additionally, no ISR or grade 3 or higher TRAE were reported. The CR rate was 87.0%. Short-term infusion of fosnetupitant, administered over 15 minutes, was demonstrated to be safe and effective for patients receiving HEC or MEC (Japan Registry of Clinical Trials Trial ID: jRCT1041220144).

Comparison of the effects of Aprepitant and Granisetron in preventing postoperative nausea and vomiting (PONV) in patients undergoing Laparoscopic Cholecystectomy: A double-blind, randomized, controlled study

Background: Postoperative nausea and vomiting (PONV) is one of the most common findings in the first 24 hours after surgery, occurring in 30% of all patients and up to 80% of high-risk patients. We compared aprepitant (a neurokinin-1 receptor antagonist) and granisetron in preventing PONV in patients who underwent laparoscopic cholecystectomy (LC). Methods: Sixty-one patients (aged 18-90) and the American Society of Anesthesiologists (ASA) I-II class who underwent LC under general anesthesia were enrolled in the study. Our study aimed to compare the incidence of PONV between 0-6, 6-12, and 6-24 hours postoperatively and the need for additional antiemetic requirements primarily and, secondly, detecting VAS scores and additional analgesic requirements for aprepitant and granisetron. Results: Our study observed similar PONV changes in both groups at 0-6 hours. A significantly lower VDS was observed in group A at 30-60 minutes compared to group G (p=0.10). There was no significant difference between groups at other intervals until the 120th minute. Between 6 and 12 hours, Group A had a lower VDS (Verbal Descriptive Scale) than Group G, but there was no statistically significant difference (P&gt;0.05). There was no significant difference between the groups regarding VAS scores, additional analgesic requirements, and adverse effects on patients (p&gt;0.05). Conclusion: We observed that aprepitant may be more effective than granisetron in preventing PONV and can be used safely in patients undergoing LC.

Neurokinin-1 receptors in the nucleus accumbens shell influence sensitivity to social defeat stress and stress-induced alcohol consumption in male mice

Chronic social defeat stress (SDS) is a widely employed preclinical model of depression involving repeated exposure to physical defeats using a resident-intruder model in male mice. Exposure to SDS induces depressive-like phenotypes including anhedonia, social withdrawal, and increased drug and alcohol consumption. Previously, we found that expression of the neurokinin-1 receptor (NK1R) is increased in the nucleus accumbens (NAC) of mice that are sensitive to this stressor and increase their alcohol intake. The NK1R is the endogenous receptor for the neuropeptide substance P (SP) and plays a prominent role in stress, anxiety, and addiction. In the present study, we assessed changes in NK1R protein levels in the NAC shell and implemented viral vector strategies to demonstrate a functional role of the NK1R in sensitivity to SDS. Specifically, we found that NK1R protein levels were increased in the NAC shell following SDS exposure. Next, we found that NK1R overexpression in the NAC shell increased the sensitivity to SDS and stress-induced alcohol consumption. Together, these experiments provide evidence for a role of the NK1R in the NAC shell in the sensitivity to SDS and the subsequent escalation in alcohol intake.

Neurokinin receptor antagonists as potential nonhormone treatments for vasomotor symptoms.

Managing menopause symptoms is challenging for women unable or unwilling to take hormone therapy. All nonhormone options thus far have shown less overall efficacy compared with hormone therapy and significant adverse events that limit their use. New science has identified the source of vasomotor symptoms, achieving relief of these bothersome symptoms by directly targeting the neurokinin 3 receptor and its related pathways. This Practice Pearl reviews the clinical data available on neurokinin receptor antagonists.

Electroacupuncture alleviates neuropathic pain by regulating hippocampal SP/NK1R/ARRB1 pathway.

To observe the effect of electroacupuncture (EA) on pain, anxiety like behavior, and substance P(SP) /neurokinin-1 receptor (NK1R) /β -arrestin 1(ARRB1) pathway related protein expression in hippocampus of chronic constriction injury (CCI) rats, so as to explore its mechanisms underlying improvement of neuropathic pain. Twenty-seven male SD rats were randomly divided into sham operation, model and EA groups, with 9 rats in each group. The CCI model was established by ligature of the left sciatic nerve. On the 8th day following modeling, EA (2 Hz, 0.5-1.5 mA) was applied to the left "Huantiao" (GB34) and "Yanglingquan" (GB34) for 30 min, once every other day for 13 times. Mechanical paw withdrawal threshold (MWT), thermal paw withdrawal threshold (TWL) and difference of the weight distribution of the hind limbs were detected before operation and at the 5th, 9th, 17th, 25th and 33rd days after operation. Open field test was used to evaluate the anxiety-like behavior of rats. The content of SP in hippocampus was determined by ELISA. The protein expression of NK1R and ARRB1 in hippocampus was detected by Western blot. Compared with the sham operation group, the MWT and TWL of the left hind limb at the 5th, 9th, 17th, 25th and 33rd days after operation, the time of entering the central area and the total distance of movement, and the content of SP in the hippocampus were significantly decreased (P<0.001, P<0.01), while the difference of the weight distribution of the hind limbs at the 5th, 9th, 17th, 25th and 33rd days after operation and the protein expression of NK1R and ARRB1 were significantly increased (P<0.001, P<0.05) in the model group. After EA intervention, the MWT and TWL of the left hind limb, the time of entering the central area and the total moving distance, and the expression of SP in the hippocampus were significantly increased (P<0.01, P<0.001, P<0.05), while the difference in the weight distribution of the hind limbs was significantly reduced, and the expression of NK1R and ARRB1 protein in the hippocampus were significantly decreased (P<0.001, P<0.05) in the EA group. EA can effectively improve the pain and anxiety behaviors in CCI rats, and reverse the abnormal expression of SP, NK1R and ARRB1 proteins in the hippocampus, which may be related to its effects in regulating the SP/NK1R/ARRB1 pathway in the hippocampus.

Investigation of the relationship between prolactin and infertility by expression levels of kisspeptin (KISS1), KISS1 receptor, neurokinin (NK), NK receptor genes

Investigation of the relationship between prolactin and infertility by expression levels of kisspeptin (KISS1), KISS1 receptor, neurokinin (NK), NK receptor genes

Central and peripheral mechanisms underlying respiratory deficits in a mouse model of accelerated senescence.

Aging invariably decreases sensory and motor stimuli and affects several neuronal systems and their connectivity to key brain regions, including those involved in breathing. Nevertheless, further investigation is needed to fully comprehend the link between senescence and respiratory function. Here, we investigate whether a mouse model of accelerated senescence could develop central and peripheral respiratory abnormalities. Adult male Senescence Accelerated Mouse Prone 8 (SAMP8) and the control SAMR1 mice (10months old) were used. Ventilatory parameters were assessed by whole-body plethysmography, and measurements of respiratory input impedance were performed. SAMP8 mice exhibited a reduction in the density of neurokinin-1 receptor immunoreactivity in the entire ventral respiratory column. Physiological experiments showed that SAMP8 mice exhibited a decreased tachypneic response to hypoxia (FiO2 = 0.08; 10min) or hypercapnia (FiCO2 = 0.07; 10min). Additionally, the ventilatory response to hypercapnia increased further due to higher tidal volume. Measurements of respiratory mechanics in SAMP8 mice showed decreased static compliance (Cstat), inspiratory capacity (IC), resistance (Rn), and elastance (H) at different ages (3, 6, and 10months old). SAMP8 mice also have a decrease in contractile response to methacholine compared to SAMR1. In conclusion, our findings indicate that SAMP8 mice display a loss of the NK1-expressing neurons in the respiratory brainstem centers, along with impairments in both central and peripheral respiratory mechanisms. These observations suggest a potential impact on breathing in a senescence animal model.

Comparison of aprepitant versus ondansetron for prevention of postoperative nausea and vomiting: A systematic review and meta-analysis with trial sequential analysis.

Postoperative nausea and vomiting (PONV) is a common complication after surgery. Preventing PONV in high-risk patients often requires a multimodal approach combining antiemetic drugs with diverse mechanisms. While aprepitant, a neurokinin-1 receptor antagonist, is recognised as highly effective for PONV prevention, uncertainties remain regarding its effectiveness. This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The analysis assessed the effectiveness of aprepitant (A), aprepitant plus ondansetron (AO) and aprepitant plus dexamethasone and ondansetron (ADO) in preventing PONV compared to ondansetron alone (O) or in combination with dexamethasone (DO). In the analysis of 12 studies involving 2729 patients, aprepitant demonstrated significant efficacy in preventing PONV compared to ondansetron alone (A versus [vs.] O: PONV incidence 12.5% vs. 28.5%, relative risk [RR] = 0.45, P < 0.001; complete response rate 55.97% vs. 50.35%, RR = 1.13, P = 0.010). The combination of aprepitant with ondansetron (AO) also showed a significantly lower incidence of PONV compared to ondansetron alone (11.3% vs. 26.8%, RR = 0.43, P < 0.001) and a higher complete response rate (38.1% vs. 26.84%, RR = 1.41, P = 0.020). In addition, ADO significantly reduced PONV incidence compared to DO (ADO vs. DO: 13.63% vs. 35.38%, RR = 0.38, P = 0.006). Aprepitant, whether used alone or in combination with ondansetron or both ondansetron and dexamethasone, consistently outperforms ondansetron in achieving a complete response as it lowers vomiting rates and reduces the need for rescue therapy during the crucial 24-48-h postoperative period.

Olanzapine as Antiemetic Prophylaxis in Moderately Emetogenic Chemotherapy

The role of olanzapine has not been adequately evaluated in moderately emetogenic chemotherapy (MEC) regimens with or without neurokinin-1 receptor antagonists. To evaluate whether addition of olanzapine to an MEC regimen reduces nausea, vomiting, and use of nausea rescue medications among patients with solid malignant tumors. This multicenter, open-label phase 3 randomized clinical trial included patients aged 18 years or older with solid malignant tumors who were receiving oxaliplatin-, carboplatin-, or irinotecan-based chemotherapy. The trial was conducted at 3 institutes in India from March 26, 2019, to August 26, 2023; the final cutoff date for analysis was September 10, 2023. Patients were randomized 1:1 to dexamethasone, aprepitant, and palonosetron with olanzapine (experimental group) or without olanzapine (observation group). The experimental group received 10 mg of olanzapine orally once at night on days 1 through 3 of the chemotherapy regimen. The primary end point was complete response (CR), defined as the proportion of patients with no vomiting, no significant nausea (scored as <5 on a visual analog scale of 1 to 100), and no use of rescue medications for nausea. Secondary end points included the proportion of patients experiencing nausea and chemotherapy-induced nausea and vomiting (CINV), receiving rescue medications, and experiencing adverse events. A total of 560 patients (259 [64%] male; median age, 51 years [range, 19-80 years]) were randomized. The analysis included 544 patients with evaluable data (274 assigned to olanzapine and 270 to observation). Baseline characteristics were evenly matched between the 2 groups. The proportion of patients with CR was significantly greater in the group with (248 [91%]) than without (222 [82%]) olanzapine in the overall 120-hour treatment period (P = .005). Likewise, there were significant differences between the olanzapine and observation groups for nausea control (264 [96%] vs 234 [87%]; P < .001) and CINV (262 [96%] vs 245 [91%]; P = .02) during the overall assessment period, and the proportion of patients receiving rescue medications significantly increased in the observation group (30 [11%]) compared with the olanzapine group (11 [4%]) (P = .001). Grade 1 somnolence was reported by 27 patients (10%) following administration of chemotherapy and olanzapine and by no patients in the observation group. In this randomized clinical trial, the addition of olanzapine significantly improved CR rates as well as nausea and vomiting prevention rates in chemotherapy-naive patients who were receiving MEC regimens containing oxaliplatin, carboplatin, or irinotecan. These findings suggest that use of olanzapine should be considered as one of the standards of care in these chemotherapy regimens. Clinical Trials Registry-India (CTRI) Identifier: CTRI/2018/12/016643.