Neurokinin Research Articles

In brief: New warning for fezolinetant (Veozah).

The FDA has required a new warning in the label of the oral selective neurokinin 3 (NK3) receptor antagonist fezolinetant (Veozah) about the risk of hepatoxicity.1,2 The label of fezolinetant, which was approved by the FDA in 2023 for treatment of moderate to severe vasomotor symptoms due to menopause, already contained a warning about hepatic transaminase elevations associated with use of the drug.

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.

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.

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

Decreases in mucosally-evoked tachykinin signaling pathways can explain age-related reductions in murine colonic motility patterns.

Increasing age increases the incidence of chronic constipation and fecal impaction. The contribution of the natural aging process to this phenotype is unclear. This study explored the effects of age on key motility patterns in the murine colon and determined the contribution that altered neurokinin 2 (NK2) -mediated signaling made to the aging phenotype. Mucosal reflexes, colonic migrating motor complexes (CMMCs) and colonic motility assays were explored in isolated exvivo colons from 3, 12-14, 18- and 24-months old mice and the NK2-mediated response determined. Electrical field stimulation (EFS) or exogenous drug application were used to explore the role of the mucosa in colonic segments. Aging reduced the force of contraction of the distal colon mucosal reflex, the frequency and force of contraction of CMMCs and the NK2-mediated component of both motility patterns. Ondansetron, a 5-HT3 receptor antagonist, blocked a component of both motility patterns in full thickness but not in mucosa-free segments of the distal colon. 5, hydroxytryptamine (5-HT) and EFS-evoked NK2-dependent contractions were reduced with increasing age. Smooth muscle sensitivity to 5-HT or neurokinin A (NKA) was not altered with age. In isolated colon motility assays application of NKA decreased transit time in 24-months colon and the NK2 antagonist GR159897 increased transit times in both 3- and 24-months old colons. Aging impairs key motility patterns in the murine colon. These changes involve a decrease in mucosally-evoked NK2-mediated signaling. Targeting NK2-mediated signaling may provide a novel approach to treating age-related motility disorders in the lower bowel.

Adequate antiemetic treatment in patients receiving antitumor drug therapy

Despite the widespread use of immuno-oncological and targeted therapy in the treatment of malignant tumors, in real clinical practice the role of chemotherapy is still significant, used both in mono regimen and in combination with other antitumor drugs. Cytostatics cause a wide range of adverse events, which are often the cause of dose reduction, cyclical disorders, or even discontinuation of therapy. One of the most common symptoms is chemotherapy-induced nausea and vomiting which affect not only the quality of life, but also the results of treatment. It is important to address these issues from prevention and treatment perspectives so that patients remain committed to their treatment regimens. Since nausea and vomiting induced by chemotherapy are classified into 5 different types, the main medications for prevention and treatment include 5-hydroxytryptamine type 3 (5-HT3) and neurokinin-1 (NK1) receptor antagonists and corticosteroids. Simultaneous use of drugs from the groups of second-generation NK1 receptor blockers and 5-HT3 receptor blockers, for example: netupitant + palonosetron in combination with corticosteroids, makes it possible to achieve maximum antiemetic effect, even with the most emetogenic antitumor treatment regimens.

Phytoconstituents Targeting the Serotonin 5-HT3 Receptor: Promising Therapeutic Strategies for Neurological Disorders.

The 5-hydroxytryptamine-3 receptor (5-HT3R), a subtype of serotonin receptor, is a ligand-gated ion channel crucial in mediating fast synaptic transmission in the central and peripheral nervous systems. This receptor significantly influences various neurological activities, encompassing neurotransmission, mood regulation, and cognitive processing; hence, it may serve as an innovative target for neurological disorders. Multiple studies have revealed promising results regarding the beneficial effects of these phytoconstituents and extracts on conditions such as nausea, vomiting, neuropathic pain depression, anxiety, Alzheimer's disease, cognition, epilepsy, sleep, and dyskinesia via modulation of 5-HT3R in the pathophysiology of neurological disorder. The review delves into a detailed exploration of in silico, in vitro, and in vivo studies and clinical studies that discussed phytoconstituents acting on 5-HT3R and attenuates difficulties in neurological diseases. The diverse mechanisms by which plant-derived phytoconstituents influence 5-HT3R activity offer exciting avenues for developing innovative therapeutic interventions. Besides producing an agonistic or antagonistic effect, some phytoconstituents exert modulatory effects on 5-HT3R activity through multifaceted mechanisms. These include γ-aminobutyric acid and cholinergic neuronal pathways, interactions with neurokinin (NK)-1, NK2, serotonergic, and γ-aminobutyric acid(GABA)ergic systems, dopaminergic influences, and mediation of calcium ions release and inflammatory cascades. Notably, the phytoconstituent's capacity to reduce oxidative stress has also emerged as a significant factor contributing to their modulatory role. Despite the promising implications, there is currently a dearth of exploration needed to understand the effect of phytochemicals on the 5-HT3R. Comprehensive preclinical and clinical research is of the utmost importance to broaden our knowledge of the potential therapeutic benefits associated with these substances.

Stimulation of the calcium-sensing receptor induces relaxations through CGRP and NK1 receptor-mediated pathways in male rat mesenteric arteries.

Stimulation of the calcium-sensing receptor (CaSR) regulates vascular contractility, but cellular mechanisms involved remain unclear. This study investigated the role of perivascular sensory nerves in CaSR-induced relaxations of male rat mesenteric arteries. In fluorescence studies, colocalisation between synaptophysin, a synaptic vesicle marker, and the CaSR was present in the adventitial layer of arterial segments. Using wire myography, increasing external Ca2+ concentration ([Ca2+]o) from 1 to 10 mM induced vasorelaxations, previously shown to involve the CaSR, which were inhibited by pretreatment with capsaicin. [Ca2+]o-induced vasorelaxations were partially reduced by the calcitonin gene-related peptide (CGRP) receptor blockers, CGRP 8-37 and BIBN 4096, and the neurokinin 1 (NK1) receptor blocker L733,060. The inhibitory effect of CGRP 8-37 required a functional endothelium whereas the inhibitory action of L733,060 did not. Complete inhibition of [Ca2+]o-induced vasorelaxations occurred when CGRP 8-37 and L733,060 were applied together. [Ca2+]o-induced vasorelaxations in the presence of capsaicin were abolished by the ATP-dependent K+ channel (KATP) blocker PNU 37883, but unaffected by the endothelium nitric oxide synthase (eNOS) inhibitor L-NAME. We suggest that the CaSR on perivascular sensory nerves mediate relaxations in rat mesenteric arteries via endothelium-dependent and -independent mechanisms involving CGRP and NK1 receptor-activated NO production and KATP channels, respectively.

Abstract SS02-02: Hormone Replacement and Alternatives for Relief of Vasomotor Symptoms in Women at Increased Risk for Breast Cancer

Abstract 70% of women will experience vasomotor symptoms sufficient to impact their quality of life during menopause transition and the early menopause. These symptoms are thought result from neurotransmitter imbalances resulting from ovarian hormone reductions and hypersecretion of gonadotropins. Increases in gonadotropins result in neurotransmitter triggered stimulation of the neurokinin 3 (NK3) receptor and thermoregulatory imbalance. Estrogen deficiency also reduces serotonin which can also trigger increases in hot flashes, and sleep disturbances. Vasomotor symptoms last on the average for 7 years until acclimation to persistent low estrogen levels occurs. Estrogen +/- progestin replacement therapy is associated with the greatest likelihood of vasomotor symptom relief as it reduces gonadotropin and NK3 receptor signaling and increases serotonin. Progestins also increase the neuroinhibitory transmitter gamma-aminobutyric acid (GABA) which improves sleep quality. There continues to be confusion on the part of providers and patients regarding the excess risk of breast cancer and thromboembolic events as these risks are affected by type of agent, route of delivery, age, duration of treatment, and presence of obesity. The majority of placebo controlled randomized clinical trial data on hormone replacement with estrogen or estrogen + a progestin comes from the Women’s Health Initiative (WHI) for women 50-79 in which oral conjugated estrogen (CE) 0.625 mg was used as the estrogen for women without a uterus and medroxyprogesterone acetate (MPA) was added to CE for women with a uterus to protect against endometrial hyperplasia and cancer. The median age at entry to WHI that trial was 63 and a substantial proportion had previously taken hormones. Large longitudinal cohort studies have been helpful in assessing risks in women starting hormones at a more clinically relevant age (45-55) and with hormonal preparations other than oral CE and MPA. Five to seven years of estrogen alone results in minimal if any increased risk for breast cancer. However, combined estrogen+ progestin replacement for women over 50, necessary for women with a uterus, results in an ~ 30 % relative increased risk for breast cancer if taken for up to 5 years and a doubling of risk with 10 years of treatment. So called bioidentical hormones often compounded as oral troches of estradiol, progesterone, and testosterone, are also associated with increased breast cancer risk. Vaginal hormones have not been found to increase risk for breast cancer. Increased risk of thromboembolism is predominately observed in women over 50 using oral as opposed to transdermal preparations. Increased risk for stroke and dementia was observed in the WHI again with oral hormones in women over 65. In the WHI there was no increase in cancer related, cardiovascular or overall mortality with estrogen or estrogen and progestin. For high-risk peri and post-menopausal women with who would like to reduce/alleviate their vasomotor symptoms with no increase in risk for breast cancer there are several options: 1) the tissue selective estrogen complex bazedoxifene (BZA) combined with conjugated estrogen (CE) 2) the non-hormonal option of NK3 receptor antagonists such as fezolinetant ( 3) non-hormonal options of gabapentin, selective serotonin reuptake inhibitors (SSRI) and serotonin and norepinephrine uptake inhibitors (SNRI). BZA and CE and fezolinetant are reported to reduce hot flashes in 70% or more of individuals with paroxetine effectiveness reported as 50%. All three are FDA approved for reduction of vasomotor symptoms. The combination of BZA and CE is also being investigated for breast cancer risk reduction. These agents differ with respect to side effects with increased risk of blood clots for bazedoxifene and conjugated estrogen, increased risk of nausea, diarrhea, and liver dysfunction for fezolinetant and drowsiness and dry mouth for SSRIs. Drug costs may also dramatically affect insurance coverage and patient uptake of a particular strategy. A recent online perusal of a popular site for finding the lowest drug price suggested substantial differences in the cost of drugs for relief of vasomotor symptoms. The approximate cost for a 30- day supply of oral estradiol was $30, estradiol transdermal patches $35, oral progesterone $15, combined estradiol and levonorgestrel transdermal patches $240, oral CE $200, oral CE + medoxyprogesterone acetate $240, and for BZA+ CE $200. For non-hormonal therapies the cost of 30 days of gabapentin was $11, paroxetine $30 and fezolinetant $550. Crandall, Mehta, and Manson JAMA 2023 329:405-420 Collaborative Group on Hormonal Factors in Breast Cancer Lancet 2019 394: 1159-1168 Fabian et al Ca Prev Res 2019 10:711-720 Modi and Dhillo Neuroendocrinology 2019 109:242–248 Citation Format: C. Fabian. Hormone Replacement and Alternatives for Relief of Vasomotor Symptoms in Women at Increased Risk for Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr SS02-02.

Abstract RF01-08: A randomized, open-label phase III trial Evaluating Low-Dose Vs standard-dose Olanzapine with triple Antiemetic therapy for Prevention of highly emetogenic chemotherapy- induced Nausea and vomiting in solid tumors (OLAnzaPiNE)

Abstract Background Chemotherapy induced nausea and vomiting (CINV) is a major adverse event for cancer patients. Olanzapine (OLZ) in standard 10 mg dose along with triple antiemetics (TAE), has shown effectiveness in treating CINV with highly emetogenic chemotherapy (HEC), however, significant day time somnolence (DTS) precludes its widespread use. Steroids related side effects are another major concern. Hence, a lower dose of OLZ, with single dose (SD) steroid use is worth exploring in a randomized fashion. Methods Solid tumors planned for anthracycline-cyclophosphamide & high-dose cisplatin chemotherapy was randomized (1:1) to receive either 10mg OLZ (standard arm) or 2.5mg (experimental arm) till day 4 with TAE regimen [5-hydroxytryptamine type 3 (5-HT3) receptor antagonists, dexamethasone (SD, without delayed doses), and neurokinin-1 (NK1) receptor antagonists] in both arms. Primary objective was to evaluate Complete control rate (CCR) defined as proportion of subjects with no emetic episodes (EE), no use of rescue medications (RM), no or mild nausea assessed in overall phase (OP) =0-120 hours(h) in both groups. Secondary objectives were to compare two groups for the CCR in acute(AP) and delayed phase(DP);Complete response rate (CRR)=no EE and no use of RM in AP(0- 24h), DP(25-120h) and OP; Total control rate(TCR)= no EE, no use of RM, and no nausea) in AP, DP, OP; Time to treatment failure(TTF), defined as mean duration from chemotherapy initiation to first episode of nausea, EE, use of RM; Incidence of significant daytime somnolence(DTS).Tertiary objectives were effect on appetite loss. Subjects maintained a daily record of nausea, EE, RM use with the severity graded on a four-category scale. Statistical analysis CCR, CRR, TCR are given in counts and proportions. Occurrence of nausea, EE, DTS and their grades were compared using Chi-square test. Results A total of 275 subjects were enrolled, among them 267 were analyzable, inclusive of 132 subjects in 2.5mg and135 in 10mg arms with well-balanced baseline characteristics (Table 1) Proportion of patients with CCR in OP (Primary end point) in 2.5mg vs. 10mg arms were, 44.7 % vs. 43.7 % (P = 0.87) respectively. CCR in 2.5mg vs. 10mg arms in AP, DP were 50% vs. 48.9%(p=0.856) and 50.8% vs. 58.5% (P=0.203) respectively. CRR in 2.5mg vs. 10mg in AP, DP and OP were 56.1% vs. 57 % (P=0.872), 55.3% vs. 63% (P = 0.203), and 50.8 % vs. 51.1% (P=0.954), respectively. TCR in2.5mg vs. 10mg in AP, DP, and OP were25% vs. 23 % (P=0.697), 20.5% vs. 22% (P = 0.725), and 13.6 % vs. 15.6% (P=0.657), respectively. Subjects receiving 2.5 mg as compared with those receiving 10 mg, had statistically significant decreased DTS on overall grades 65.2%vs 89.6% vs. (p < 0.001); severe grade DTS was more on day1 i.e., 4.5%vs. 40% (p < 0.001) and although successively reduced from day 2-5 in both the arms, however, 2.5 mg fared better on all the days (table 1). No statistically significant effect of reduced appetite noted in 2.5mg vs. 10mg i.e., 17.4% vs. 24.4 %(p=0.208) Conclusion Low dose olanzapine (2.5mg) is non inferior to 10mg olanzapine in controlling CINV without requirement of delayed steroids, and is superior with respect to DTS (all days, all grades, severe grades) in subjects receiving HEC. This merits wide recognition as a new steroid sparing antiemetic regimen of choice with HEC. Demographic data, Clinical characteristics and Outcomes Citation Format: Jyoti Bajpai, Venkatesh Kapu, Sushmita Rath, Sravan Kumar, Anbarasan Sekar, Srikanth Anne, Akash Pawar, Sujay Srinivas, Prabhat Bhargava, Seema Gulia, Rajiv Sarin, Rajendra Badwe, Sudeep Gupta. A randomized, open-label phase III trial Evaluating Low-Dose Vs standard-dose Olanzapine with triple Antiemetic therapy for Prevention of highly emetogenic chemotherapy- induced Nausea and vomiting in solid tumors (OLAnzaPiNE) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr RF01-08.

Neurokinin A reduces the influx of inflammatory cells into the skin in a mast-cell dependent manner

Abstract Cutaneous mast cells promote immune responses but are also involved in reducing inflammation and in promoting immune resolution. Mechanisms initiating the anti-inflammatory function of mast cells are poorly defined. Mast cells reside in close proximity to neurons and their activation is modulated by neuropeptides, including the tachykinin family members. Neurokinin A (NKA) is an understudied tachykinin family member that limits cutaneous inflammation in a murine contact hypersensitivity (CHS) model but increases inflammation in colitis. In this study, the regulatory function of NKA in cutaneous inflammation is mechanistically evaluated using a robust model of DNFB-induced CHS. Administration of NKA prior to sensitization inhibited the expression of inflammatory cytokines and chemokines, including Il1b, Il6 and Ccl2. Correspondingly, NKA reduced recruitment of CCR2+ neutrophils and inflammatory monocytes to the skin. In mast cell-deficient Mcpt5Cre+ x Rosa26DTA and in mice in which mast cells do not produce IL-10 (Mcpt5Cre+ x Il10fl/fl) the capacity for NKA to reduce cytokines and chemokines was diminished. Lastly, in skin explant NKA diminished IL-1b and CCL2, genes upregulated after DNFB-treatment. Collectively, these data suggest that NKA reduces inflammation in the skin in a mast cell/IL-10 dependent manner and demonstrate a novel regulatory pathway for NKA in the skin that acts on mast cells to unleash their potential to reduce cutaneous inflammation.

Rapid elucidation of agonist-driven regulation of the neurokinin 1 receptor using a GPCR phosphorylation immunoassay

Agonist-induced phosphorylation is a crucial step in the activation/deactivation cycle of G protein-coupled receptors (GPCRs), but direct determination of individual phosphorylation events has remained a major challenge. We have recently developed a bead-based immunoassay for the quantitative assessment of agonist-induced GPCR phosphorylation that can be performed entirely in 96-well plates, thus eliminating the need for western blot analysis. In the present study, we adapted this assay to three novel phosphosite-specific antibodies directed against the neurokinin 1 (NK1) receptor, namely pS338/pT339-NK1, pT344/pS347-NK1, and pT356/pT357-NK1. We found that substance P (SP) stimulated concentration-dependent phosphorylation of all three sites, which could be completely blocked in the presence of the NK1 receptor antagonist aprepitant. The other two endogenous ligands of the tachykinin family, neurokinin A (NKA) and neurokinin B (NKB), were also able to induce NK1 receptor phosphorylation, but to a much lesser extent than substance P. Interestingly, substance P promoted phosphorylation of the two distal sites more efficiently than that of the proximal site. The proximal site was identified as a substrate for phosphorylation by protein kinase C. Analysis of GPCR kinase (GRK)-knockout cells revealed that phosphorylation was mediated by all four GRK isoforms to similar extents at the T344/S347 and the T356/T357 cluster. Knockout of all GRKs resulted in abolition of all phosphorylation signals highlighting the importance of these kinases in agonist-mediated receptor phosphorylation. Thus, the 7TM phosphorylation assay technology allows for rapid and detailed analyses of GPCR phosphorylation.

Semi-synthetic nanobody-ligand conjugates exhibit tunable signaling properties and enhanced transcriptional outputs at neurokinin receptor-1.

Antibodies have proven highly valuable for therapeutic development; however, they are typically poor candidates for applications that require activation of G protein-coupled receptors (GPCRs), the largest collection of targets for clinically approved drugs. Nanobodies (Nbs), the smallest antibody fragments retaining full antigen-binding capacity, have emerged as promising tools for pharmacologic applications, including GPCR modulation. Past work has shown that conjugation of Nbs with ligands can provide GPCR agonists that exhibit improved activity and selectivity compared to their parent ligands. The neurokinin-1 receptor (NK1R), a GPCR targeted for the treatment of pain, is activated by peptide agonists such as Substance P (SP) and neurokinin A (NKA), which induce signaling through multiple pathways (Gs , Gq and β-arrestin). In this study, we investigated whether conjugating NK1R ligands with Nbs that bind to a separate location on the receptor would provide chimeric compounds with distinctive signaling properties. We employed sortase A-mediated ligation to generate several conjugates consisting of Nbs linked to NK1R ligands. Many of these conjugates exhibited divergent and unexpected signaling properties and transcriptional outputs. For example, some Nb-NKA conjugates showed enhanced receptor binding capacity, high potency partial agonism, prolonged cAMP production, and an increase in transcriptional output associated with Gs signaling; whereas other conjugates were virtually inactive. Nanobody conjugation caused only minor alterations in ligand-induced upstream Gq signaling with unexpected enhancements in transcriptional (downstream) responses. Our findings underscore the potential of nanobody conjugation for providing compounds with advantageous properties such as biased agonism, prolonged duration of action, and enhanced transcriptional responses. These compounds hold promise not only for facilitating fundamental research on GPCR signal transduction mechanisms but also for the development of more potent and enduring therapeutics.

The Effects of Tachykinin1 Gene Products on Prepubertal Dabry's Sturgeon (Acipenser dabrynus) Pituitary Hormone Secretion and Gene Expression.

As an ancient and endangered species unique to the Yangtze River in China, the wild population of the Dabry's sturgeon has become scarce. Due to the long time till the first sexual maturity of Dabry's sturgeon, the population of artificially bred Dabry's sturgeon recovered slowly. As a member of the tachykinin family, TAC1 has been reported to have a variety of functions in mammals such as pain control, smooth muscle contraction and reproductive cycle regulation, but the function of Tac1 in fish has been rarely reported. In this study, we synthesized two tac1 gene products, Substance P (SP) and neurokinin A (NKA), and further verified the effect of two tac1 gene products on the secretion of related hormones in the pituitary of Dabry's Sturgeon by intraperitoneal injection and co-culture of primary cells. Expression studies revealed that the newly cloned tac1 were mainly distributed in the hypothalamus and pituitary tissue of the brain. In prepubertal Dabry's sturgeon, this study showed that the two gonadotropins' mRNA levels in pituitary tissue can be significantly increased by SP and NKA through intraperitoneal injection, and the LH protein level in serum was also increased. Further study showed that both NKA and SP could promote the two gonadotropins' mRNA expression in pituitary cells of Dabry's sturgeon. In addition, we explored the optimal dose and time of SP and NKA on pituitary cells is 24 h and over 10 nM. These results, as a whole, suggested that tac1 gene products play an important role in gonadotropin release and gonadal development in prepubertal Dabry's sturgeon.

Antagonists of somatostatin and NK1 receptors synergistically induce catalepsy in middle-aged Wistar rats

Objectives: A decrease in levels of somatostatin (SST) and substance P (SP) is observed in the parkinsonian brain. Previously, brain SST deficit in rats simulated by i.c.v. injections of SST receptor antagonist, cyclosomatostatin (cSST), was found to promote the development of catalepsy. The role of SP, a natural ligand of neurokinin-1 (NK1) receptors, in the development of catalepsy is currently unclear. Here, we evaluated whether simultaneous blockade of central somatostatin and NK1 receptors is able to initiate catalepsy and affect dopamine turnover in the nigrostriatal area of the brain.\nMaterials and methods: The experiments were carried out on middle-aged Wistar rats. The blockade of somatostatin and NK1 receptors was simulated by intracerebroventricular injections of cSST and substance L-733,060, respectively. Catalepsy was evaluated by the bar test. The levels of dopamine and its metabolites in the dorsal striatum and substantia nigra were measured by using HPLC.\nResults: No catalepsy was induced by cSST at 1.0 µg and L-733,060 at 10.0 ng injected separately. However, co-administration of these agents initiated catalepsy and influenced dopamine metabolism in the nigrostriatal area. Cataleptogenic action of the combination was reversed by SP. \nConclusion: The present findings testify that there is some sort of synergy between cSST and L-733,060 in initiation of catalepsy. In the light of these data, PD-related simultaneous brain deficit in SST and SP might be relevant for pathogenesis of extrapyramidal dysfunctions. Given the presented results, the processes mediated by central SST and NK1 receptors may be potential therapeutic targets for parkinsonism.

OLANZAPINE FOR NAUSEA AND VOMITING IN VARIOUS ETIOLOGIES : A REVIEW

Nausea is an unpleasant response followed by the risk of vomiting that results rapid forced ejection of gastric substance from the stomach upwards and out of the mouth. The Gastrointestinal tract, vestibular system, and thalamus are the sites that cause this event. Serotonin type 3 (5-HT3), Mu, neurokinin-1 (NK-1), kappa opioids, dopamine type 2 (D2) are CTZ receptors that cause emesis. 5-HT3 antagonists, antihistamines, and phenothiazines are common antiemetic agents. Olanzapine is an atypical antipsychotic second-generation medication with antiemetic properties. This article review used a classical method to identify studies related to the mechanism and efficacy of olanzapine as an antiemetic. The journal article related to olanzapine in nausea and vomiting that published on 2002 until 2022 for critical appraisal. The purpose of this literature review is to provide a review of antiemetics, especially olanzapine as a therapy option, as well as to evaluate the mechanism and efficacy of olanzapine. The activity of olanzapine with several receptors associated with nausea and vomiting suggests that it may have antiemetic activity. Olanzapine inhibits the 5-HT2C receptor, which is located near small intestine enterochromaffin cells and is required for the emetic response. In CINV therapy, research suggests combining olanzapine 10 mg with a 5-HT3 antagonist, NK-1 antagonist, dexamethasone. There is a lack of data in literature on the use of olanzapine in hyperemesis gravidarum. From the review we concluded that olanzapine can be considered for use as a therapy for the treatment of nausea and vomiting.

Short-term administration of Qipian®, a mixed bacterial lysate, inhibits airway inflammation in ovalbumin-induced mouse asthma by modulating cellular, humoral and neurogenic immune responses

AimsQipian® is a commercialized agent composed of extracts of three genera of commensal bacteria, and its mechanism of action on asthma is unclear. This study aimed to examine the impact of Qipian® on airway inflammation and investigate the underlying mechanisms. Materials and methodsQipian® or dexamethasone (DEX) was administered before OVA challenge in an ovalbumin-induced asthma mouse model, and then asthmatic symptoms were observed and scored. Samples of lung tissues, blood, and bronchoalveolar lavage fluid (BALF) were collected, and eosinophils (Eos), immunoglobins (Igs), and type 1 T helper (Th1)/Th2 cell cytokines were measured. Mucus production in the lung was assessed by periodic acid-Schiff (PAS) staining. The effects of Qipian® on dendritic and T regulatory (Treg) cells were investigated using flow cytometry. Key findingsThe short-term administration of Qipian® significantly inhibited the cardinal features of allergic asthma, including an elevated asthmatic behaviour score, airway inflammation and immune response. Histological analysis of the lungs showed that Qipian® attenuated airway inflammatory cell infiltration and mucus hyperproduction. Qipian® restored Th1/Th2 imbalance by decreasing interleukin (IL)-4, IL-5, and IL-13 while increasing interferon (IFN)-γ and IL-10. Further investigation revealed that Qipian® treatment induced the upregulation of CD4+CD25+Foxp3+ Treg cells and CD103+ DCs and downregulation of tachykinins neurokinin A (NKA) and NKB in the lung. SignificanceOur findings suggested that short-term treatment with Qipian® could alleviate inflammation in allergic asthma through restoring the Th1/Th2 balance by recruiting Treg cells to airways and inducing the proliferation of CD103+ DCs, which actually provides a new treatment option for asthma.

455P Assessing model-predicted neurokinin-1 (NK1) receptor occupancy (RO) of netupitant to support efficacy over an extended time period

455P Assessing model-predicted neurokinin-1 (NK1) receptor occupancy (RO) of netupitant to support efficacy over an extended time period

Differential Influences of Endogenous and Exogenous Sensory Neuropeptides on the ATP Metabolism by Soluble Ectonucleotidases in the Murine Bladder Lamina Propria.

Bladder urothelium and suburothelium/lamina propria (LP) have prominent sensory and transducer functions with the active participation of afferent neurons and urothelium-derived purine mediators such as adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), and adenosine (ADO). Effective concentrations of purines at receptor targets depend significantly on the extracellular degradation of ATP by ectonucleotidases (ENTDs). We recently reported the regulated release of soluble ENTDs (s-ENTDs) in the LP and the consequent degradation of ATP to ADP, AMP, and ADO. Afferent neurons in the LP can be activated by urothelial ATP and release peptides and other transmitters that can alter the activity of cells in their vicinity. Using a murine decentralized ex vivo detrusor-free bladder model, 1,N6-etheno-ATP (eATP) as substrate, and sensitive HPLC-FLD methodologies, we found that exogenous neuropeptides calcitonin gene-related peptide (CGRP), substance P (Sub P), neurokinin A (NKA), and pituitary adenylate cyclase-activating polypeptide [PACAP (1-38)] all increased the degradation of eATP by s-ENTDs that were released in the LP spontaneously and/or during bladder filling. Using antagonists of neuropeptide receptors, we observed that endogenous NKA did not modify the ATP hydrolysis by s-ENTDs, whereas endogenous Sub P increased both the constitutive and distention-induced release of s-ENTDs. In contrast, endogenous CGRP and PACAP (1-38) increased the distention-induced, but not the spontaneous, release of s-ENTDs. The present study puts forward the novel idea that interactions between peptidergic and purinergic signaling mechanisms in the LP have an impact on bladder excitability and functions by regulating the effective concentrations of adenine purines at effector cells in the LP.

Effect of endogenous substance P on visceral afferent signal integration in the nucleus tractus solitaries of rat brainstem slices

In the first synapse of the blood-pressure-regulating pathway, a neurokinin (NK) family peptide substance P (SP) is release with an excitatory neurotransmitter, glutamate, to enhance the sensitivity of the baroreflex responses. However, the underlying mechanisms of action are not yet well understood. The effects of NK receptor antagonists and agonists on solitary tract stimulation-evoked excitatory postsynaptic responses were recorded using whole-cell patch-clamp recordings of neurons in the medial portion of the nucleus tractus solitarius (mNTS) in the brainstem. SP reduced the amplitude of the evoked excitatory postsynaptic currents (eEPSCs) and shifted the holding current inward, in a dose-dependent manner. The concentrations of SP needed to induce such responses were different between capsaicin-sensitive unmyelinated (C-type) and capsaicin-resistant myelinated (A-type) neurons. The perfusion of a NK1 receptor antagonist, sendide, reduced the amplitude of eEPSCs in all tested neurons but did not affect the levels of the holding current. A Neurokinin type 1 receptor (NK1 receptor) agonist, [Sar9, Met(O2)11]-SP, reduced the amplitude of the eEPSCs and shifted the holding current inward in capsaicin-resistant neurons; however, it failed to induce any significant changes in the capsaicin-sensitive neurons. Furthermore, a selective Neurokinin type 3 receptor (NK3 receptor) antagonist, SB223412, failed to induce any changes in any tested neuron. In current-clamp experiments, sendide reduced solitary tract (ST)-stimulation evoked firing of action potentials in both A- and C-type neurons. [Sar9, Met(O2)11]-SP suppressed the firing of the action potentials in C-type but not A-type neurons. In spontaneous synaptic recordings, SP reduced frequency of the sEPSCs in CAP sensitive neuron but NK1 agonist reduced at capsaicin resistant neurons. Taken together, the findings show that ST activation leads to the co-transmission of SP and glutamate and enhances baroreflex sensitivity by potentiating the amplitude of eEPSC in an NK1 receptor activity-dependent manner.