Analgesic and Psychotropic Effects of a New Bradykinin Antagonist.

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

Maximakinin reversed H2O2 induced oxidative damage in rat cardiac H9c2 cells through AMPK/Akt and AMPK/ERK1/2 signaling pathways.

Maximakinin (MK), a homolog of bradykinin (BK), is extracted from skin venom of the Chinese toad Bombina maxima. Although MK has a good antihypertensive effect, its effect on myocardial cells is unclear. This study investigates the protective effect of MK on hydrogen peroxide (H2O2)-induced oxidative damage in rat cardiac H9c2 cells and explores its mechanism of action. A 3-(4,5-Dimethyl-2-Thiazolyl)-2,5-Diphenyl Tetrazolium Bromide (MTT) assay was selected to detect the effect of MK on H9c2 cell viability, while flow cytometry was used to investigate the influence of MK and H2O2 on intracellular reactive oxygen species (ROS) levels. Protein expression changes were detected by western blot. In addition, specific protein inhibitors were applied to confirm the induction of ROS-related signaling pathways by MK. MTT assay results show that MK significantly reversed H2O2-induced cell growth inhibition. Flow cytometry Dichlorodihydrofluorescein diacetate (DCFH-DA) staining shows that MK significantly reversed H2O2-induced increases in intracellular ROS production in H9c2 cells. Moreover, the addition of specific protein inhibitors suggests that MK reverses H2O2-induced oxidative damage by activating AMP-activated protein kinase (AMPK)/protein kinase B (Akt) and AMPK/extracellular-regulated kinase 1/2 (ERK1/2) pathways. Finally, an inhibitor of bradykinin B2 receptors (B2Rs), HOE-140, was applied to investigate potential targets of MK in H9c2 cells. HOE-140 significantly blocked induction of AMPK/Akt and AMPK/ERK1/2 pathways by MK, suggesting a potentially important role for B2Rs in MK reversing H2O2-induced oxidative damage. Above all, MK protects against oxidative damage by inhibiting H2O2-induced ROS production in H9c2 cells. The protective mechanism of MK may be achieved by activation of B2Rs to activate downstream AMPK/Akt and AMPK/ERK1/2 pathways.

Icatibant averting mechanical ventilation in acute ischemic stroke patient with alteplase-induced orolingual angioedema.

BACKGROUND AND PURPOSE: Orolingual angioedema (OA) represents a rare but life-threatening complication among patients with acute ischemic stroke treated with intravenous thrombolysis with alteplase. Novel agents, including icatibant, are recommended in resistant patients with alteplase-induced OA who have failed to respond to first-line therapies including corticosteroids, antihistamines, and/or adrenaline. METHODS: We present a patient with alteplase-induced OA who showed substantial clinical improvement following the administration of icatibant. RESULTS: We describe a 71-year-old woman with known arterial hypertension under treatment with angiotensin-converting enzyme inhibitor, who presented with acute ischemic stroke in the territory of the right middle cerebral artery and received intravenous alteplase. During intravenous thrombolysis, the case was complicated with OA without any response to standard anaphylactic treatment including corticosteroids, dimetindene, and adrenaline. Thirty minutes after symptom onset, icatibant, a synthetic selective bradykinin B2-receptor antagonist, was administered subcutaneously. Substantial symptomatic resolution was observed only following the icatibant administration. CONCLUSIONS: This case highlights the effectiveness of icatibant in the acute management of alteplase-induced OA. In particular, icatibant administration, following first-line therapies including corticosteroids, antihistamines, and/or adrenaline, may avert tracheostomy and intubation in resistant and refractory cases with OA following intravenous thrombolysis for acute ischemic stroke.

Bradykinin and Neurotensin Analogues as Potential Compounds in Colon Cancer Therapy.

Colorectal cancer (CRC) is one of the most lethal malignancies worldwide, so the attempts to find novel therapeutic approaches are necessary. The aim of our study was to analyze how chemical modifications influence physical, chemical, and biological properties of the two peptides, namely, bradykinin (BK) and neurotensin (NT). For this purpose, we used fourteen modified peptides, and their anti-cancers features were analyzed on the HCT116 CRC cell line. Our results confirmed that the spherical mode of a CRC cell line culture better reflects the natural tumour microenvironment. We observed that the size of the colonospheres was markedly reduced following treatment with some BK and NT analogues. The proportion of CD133+ cancer stem cells (CSCs) in colonospheres decreased following incubation with the aforementioned peptides. In our research, we found two groups of these peptides. The first group influenced all the analyzed cellular features, while the second seemed to include the most promising peptides that lowered the count of CD133+ CSCs with parallel substantial reduction in CRC cells viability. These analogues need further analysis to uncover their overall anti-cancer potential.

Safety, efficacy, and pharmacokinetics of icatibant treatment in Japanese pediatric patients with hereditary angioedema: A phase 3, open-label study.

We evaluated the safety, efficacy, and pharmacokinetics of subcutaneous weight-adjusted icatibant for the treatment of acute hereditary angioedema attacks in Japanese pediatric patients. Two patients (aged 10-13 and 6-9 years) received icatibant for a total of four attacks. Each attack was abdominal and/or cutaneous and was treated with a single icatibant injection. Mild or moderate injection-site reactions were the only adverse events reported. Time to onset of symptom relief was 0.9-1.0 h. Icatibant was rapidly absorbed, with a pharmacokinetic profile consistent with previous studies. Simulated exposure levels were consistent with non-Japanese pediatric patients. These results support the safety and efficacy of icatibant in Japanese pediatric patients.

Is Icatibant Safe for the Treatment of Hereditary Angioedema During Pregnancy?

PURPOSE OF REVIEW: Hereditary angioedema (HAE) is a disorder affecting bradykinin regulation presenting as recurrent cutaneous or mucosal swelling. Treatment options include plasma-derived or human-recombinant C1-inhibitor, icatibant, or ecallantide. Due to the lack of knowledge and experience on the topic, the treatment of choice in pregnancy is plasma-derived C1-inhibitor, and reporting any new experience is recommended. This review presents current guidelines for HAE treatment with a focus on pregnancy and reviews all experience with icatibant use during pregnancy. RECENT FINDINGS: Our experience of treating a pregnant nC1-INH HAE patient with icatibant is presented, with no adverse effects or abnormalities, to add to the growing knowledge of icatibant use during pregnancy. Considering the limited number of attacks that our patient usually experiences, which continued at more or less the same frequency during pregnancy, we feel icatibant to be a safe choice for on-demand HAE treatment during pregnancy for such cases.

Effect of ornithokinin on feeding behavior, cloacal temperature, voluntary activity and crop emptying rate in chicks.

Bradykinin is a well-studied bioactive peptide associated with several physiological functions, including vasodilation and inflammation, in mammals. However, its avian homolog, ornithokinin, has received less research attention in birds. Therefore this study aimed to investigate the effect of intraperitoneal (IP) and intracerebroventricular (ICV) injections of ornithokinin on feeding behavior, cloacal temperature, voluntary activity, crop emptying rate, and blood constituents in chicks (Gallus gallus). We also investigated the effect of lipopolysaccharide (LPS), a cell wall component of gram-negative bacteria, on ornithokinin-associated gene expression was also investigated to determine whether activation of the ornithokinin system is induced by bacterial infection. Both IP and ICV injections of ornithokinin significantly decreased feed intake, cloacal temperature, voluntary activity, and crop emptying rate in chicks, but they did not affect the plasma concentration of corticosterone. Additionally, LPS significantly increased the expression of ornithokinin B2 receptor mRNA in several organs. Hence, ornithokinin is associated with a range of physiological responses in chicks and may be related to their response to bacterial infection.

The Icatibant Outcome Survey: 10 years of experience with icatibant for patients with hereditary angioedema.

In patients with hereditary angioedema (HAE), bradykinin causes swelling episodes by activating bradykinin B2 receptors. Icatibant, a selective bradykinin B2 receptor antagonist, is approved for on-demand treatment of HAE attacks. The Icatibant Outcome Survey (IOS; NCT01034969) is an ongoing observational registry initiated in 2009 to monitor the effectiveness/safety of icatibant in routine clinical practice. As of March 2019, 549 patients with HAE type 1 or 2 from the IOS registry had been treated of 5995 total attacks. This article reviews data published from IOS over time which have demonstrated that the effectiveness of icatibant in a real-world setting is comparable to efficacy in clinical trials; one dose is effective for the majority of attacks; early treatment (facilitated by self-administration) leads to faster resolution and shorter attack duration; effectiveness/safety of icatibant has been shown across a broad range of patient subgroups, including children/adolescents and patients with HAE with normal C1 inhibitor levels; and tolerability has been demonstrated in patients aged ≥65 years. Additionally, this review highlights how IOS data have provided valuable insights into patients' diagnostic journeys and treatment behaviours across individual countries. Such findings have helped to inform clinical strategies and guidelines to optimise HAE management and limit disease burden. This research was sponsored by Takeda Development Center Americas, Inc. Takeda Development Center Americas, Inc., provided funding to Excel Medical Affairs for support in writing and editing this manuscript.

Icatibant use in Brazilian patients with hereditary angioedema (HAE) type 1 or 2 and HAE with normal C1-INH levels: findings from the Icatibant Outcome Survey Registry Study.

BACKGROUND: Hereditary angioedema can be caused by C1-Inhibitor (C1-INH) deficiency and/or dysfunction (HAE-1/2) or can occur in patients with normal C1-INH (HAE nC1-INH). METHODS: The Icatibant Outcome Survey (IOS; NCT01034969) registry monitors the safety and effectiveness of icatibant for treating acute angioedema. OBJECTIVE: Present findings from Brazilian patients with HAE-1/2 and HAE nC1-INH participating in IOS. RESULTS: 42 patients were enrolled (HAE-1/2, n = 26; HAE nC1-INH, n = 16). Median age at symptom onset was significantly lower with HAE-1/2 vs. HAE nC1-INH (10.0 vs. 16.5y, respectively; p = 0.0105), whereas median age at diagnosis (31.1 vs. 40.9y; p = 0.1276) and the median time between symptom onset and diagnosis (15.0 vs. 23.8y; p = 0.6680) were numerically lower vs. HAE nC1-INH, respectively. One icatibant dose was used for > 95% of HAE attacks. Median (range) time-to-event outcomes were shorter for patients with HAE nC1-INH vs. HAE-1/2, including time to first administration (0.5 [0-96.0] vs. 1.0 [0-94.0]h, respectively), time from first administration to complete resolution (1.0 [0-88.0] vs. 5.5 [0-96.0]h, respectively), and total attack duration (7.0 [0.3-99.0] vs. 18.5 [0.1-100.0]h, respectively). Mean (SD) time from attack onset to resolution was significantly shorter for patients with HAE nC1-INH vs. HAE-1/2 (9.8 [18.7] vs. 19.6 [24.0]h, respectively; p = 0.0174). 83 adverse events (AEs) in 42 patients were reported; most were mild (66.3%) or moderate (13.3%) and non-serious (75.9%). The most common icatibant-related AE was injection site erythema (HAE-1/2, 34.6%; HAE nC1-INH, 18.8%). STUDY LIMITATIONS: This was an observational study without a treatment comparator and that relied on patient recall. CONCLUSIONS: Findings demonstrate effectiveness and tolerability of icatibant in Brazilian HAE patients.

A multicenter, open-label, randomized, proof-of-concept phase II clinical trial to assess the efficacy and safety of icatibant in patients infected with SARS-CoV-2 (COVID-19) and admitted to hospital units without invasive mechanical ventilation: study protocol (ICAT-COVID).

BACKGROUND: COVID-19 has quickly become a global pandemic with a substantial number of deaths and is a considerable burden for healthcare systems worldwide. Although most cases are paucisymptomatic and limited to the viral infection-related symptoms, some patients evolve to a second phase, with an impaired inflammatory response (cytokine storm) that may lead to acute respiratory distress syndrome and death. This is thought to be caused by increased bradykinin synthesis. METHODS: ICAT-COVID is a multicenter, randomized, open-label, proof-of-concept phase II clinical trial assessing the clinical efficacy and safety of adding icatibant to the standard of care in patients hospitalized with COVID-19 without invasive mechanical ventilation. Patients hospitalized with a confirmed COVID-19 pneumonia diagnosis (RT-PCR or antigen test ≤ 10 days prior to randomization, and radiographic evidence of pulmonary infiltrates), rated "4" or "5" on the WHO's clinical status scale, are eligible. Patients will be randomized on a 1:1 ratio to either standard of care-plus-icatibant (experimental group) or to standard of care alone (control group). The experimental group will receive 30 mg of icatibant subcutaneously 3 times a day for 3 days (for a total of 9 doses). The expected sample size is 120 patients (60 per group) from 2 sites in Spain. Primary outcomes are the efficacy and safety of Icatibant. The main efficacy outcome is the number of patients reaching grades "2" or "1" on the WHO scale within 10 days of starting treatment. Secondary outcomes include "long-term efficacy": number of patients discharged who do not present COVID-19-related relapse or comorbidity up until 28 days after discharge, and mortality. DISCUSSION: Icatibant, a bradykinin type 2 receptor antagonist with proven effectiveness and safety against hereditary angioedema attacks, may be beneficial for COVID-19 patients by inhibiting bradykinin's action on endothelial cells and by inhibiting the SARS-CoV-2 M protease. Our working hypothesis is that treatment with standard of care-plus-icatibant is effective and safe to treat patients infected with SARS-CoV-2 admitted to hospital for pneumonia without invasive mechanical ventilation. TRIAL REGISTRATION: EudraCT 2020-002166-13. CLINICALTRIALS: gov NCT04978051.

How satisfactory is on-demand icatibant from the patients' perspective in real life?

Background: Patients' satisfaction is important for the success of the management of chronic diseases. Objective: Our aim was to evaluate the satisfaction level of the patients with hereditary angioedema (HAE) for icatibant treatment. Methods: Patients with HAE C1 esterase inhibitor (C1-INH) were evaluated by using a questionnaire that included details of their icatibant-treated attacks. Patients' demographic and clinical features were collected from their medical records and personal attack diaries. The visual analog scale was used for determining the attack severity. Results: Of the total 161 patients with HAE C1-INH, 91% had HAE type I and were included in the study. Patients reported a median (interquartile range [IQR]) attacks of 2 (0.5-3) per month and 16 (4.5-36) attacks per year. The median (IQR) frequency of attacks treated with icatibant was 6 (0-20) per year. The mean ± standard deviation (SD) duration of treatment with icatibant was 3 ± 2.3 years. The self-administration rate was 91.3%. The mean ± SD time to administration and time to onset of symptom resolution were 1.6 ± 1.1 hours and 1.7 ± 1.3 hours, respectively. There was a correlation between the time to administration and time to onset of symptom resolution (r = 0.566; p < 0.0001). A total of 125 patients (77%) reported that they were very satisfied or satisfied with icatibant. No correlation was observed between the satisfaction level and the attack sites; however, the patients with more severe attacks were more satisfied with icatibant (p < 0.0001). A total of 52 patients reported 74 mild local reactions. Systemic reactions were not observed. Conclusion: The current real-life study showed that icatibant was safe and effective. Moreover, the patients' satisfaction level with icatibant was high. We believe that the availability of icatibant should be encouraged during HAE attacks because it enables patients to be more involved in their disease management.

Vespakinin-M, a natural peptide from Vespa magnifica, promotes functional recovery in stroke mice.

Acute ischemic stroke triggers complex systemic pathological responses for which the exploration of drug resources remains a challenge. Wasp venom extracted from Vespa magnifica (Smith, 1852) is most commonly used to treat rheumatoid arthritis as well as neurological disorders. Vespakinin-M (VK), a natural peptide from wasp venom, has remained largely unexplored for stroke. Herein, we first confirmed the structure, stability, toxicity and distribution of VK as well as its penetration into the blood-brain barrier. VK (150 and 300 µg/kg, i.p.) was administered to improve stroke constructed by middle cerebral artery occlusion in mice. Our results indicate that VK promote functional recovery in mice after ischemia stroke, including an improvement of neurological impairment, reduction of infarct volume, maintenance of blood-brain barrier integrity, and an obstruction of the inflammatory response and oxidative stress. In addition, VK treatment led to reduced neuroinflammation and apoptosis associated with the activation of PI3K-AKT and inhibition of IκBα-NF-κB signaling pathways. Simultaneously, we confirmed that VK can combine with bradykinin receptor 2 (B2R) as detected by molecular docking, the B2R antagonist HOE140 could counteract the neuro-protective effects of VK on stroke in mice. Overall, targeting the VK-B2R interaction can be considered as a practical strategy for stroke therapy.

A guide to immunotherapy for COVID-19.

Immune dysregulation is an important component of the pathophysiology of COVID-19. A large body of literature has reported the effect of immune-based therapies in patients with COVID-19, with some remarkable successes such as the use of steroids or anti-cytokine therapies. However, challenges in clinical decision-making arise from the complexity of the disease phenotypes and patient heterogeneity, as well as the variable quality of evidence from immunotherapy studies. This Review aims to support clinical decision-making by providing an overview of the evidence generated by major clinical trials of host-directed therapy. We discuss patient stratification and propose an algorithm to guide the use of immunotherapy strategies in the clinic. This will not only help guide treatment decisions, but may also help to design future trials that investigate immunotherapy in other severe infections.

Role of nitric oxide, bradykinin B2 receptor, and TRPV1 in the airway alterations caused by simvastatin in rats.

Dry cough has been reported in patients receiving statin therapy. However, the underlying mechanism or other possible alterations in the airways induced by statins remain unknown. Thus, the aim of this study was to evaluate whether simvastatin promotes alterations in airways, such as bronchoconstriction and plasma extravasation, as well as the mechanism involved in these events. Using methods to detect alterations in airway resistance and plasma extravasation, we demonstrated that simvastatin [20 mg/kg, intravenous (i.v.)] caused plasma extravasation in the trachea (79.8 + 14.8 µg/g/tissue) and bronchi (73.3 + 8.8 µg/g/tissue) of rats, compared to the vehicle (34.2 + 3.6 µg/g/tissue and 29.3 + 5.3 µg/g/tissue, respectively). NG-nitro-L-arginine methyl ester (L-NAME, 30 mg/kg, intraperitoneal), a nitric oxide (NO) synthase inhibitor, Icatibant [HOE 140, 10 nmol/50 µl, intratracheal (i.t.)], a bradykinin B2 antagonist, and capsazepine (100 nmol/50 µl, i.t.), a TRPV1 antagonist, attenuated simvastatin-induced plasma extravasation. Simvastatin (5, 10 and 20 mg/kg) did not cause bronchoconstriction per se, but exacerbated the bronchoconstrictive response to bradykinin (30 nmol/kg, i.v.), a B2 agonist (0.7 + 0.1 ml/H2O), or capsaicin (30 nmol/kg, i.v.), a TRPV1 agonist (0.8 + 0.1 ml/H2O), compared to the vehicle (0.1 + 0.04 ml/H2O and 0.04 + 0.01 ml/H2O, respectively). The bronchoconstriction elicited by bradykinin (100 nmol/kg, i.v.) in simvastatin non-treated rats was inhibited by L-NAME. The exacerbation of bronchoconstriction induced by bradykinin or capsaicin in simvastatin-treated rats was inhibited by L-NAME, HOE 140 or capsazepine. These results suggest that treatment with simvastatin promotes the release of bradykinin, which, via B2 receptors, releases NO that can then activate the TRPV1 to promote plasma extravasation and bronchoconstriction.

Variability of disease activity in patients with hereditary angioedema type 1/2: longitudinal data from the Icatibant Outcome Survey.

BACKGROUND: Hereditary angioedema due to C1 inhibitor deficiency (HAE-1/2) is a chronic and debilitating disease. The unpredictable clinical course represents a significant patient burden. OBJECTIVE: To analyse longitudinal registry data from the Icatibant Outcome Survey (IOS) in order to characterize temporal changes in disease activity in patients with HAE-1/2. METHODS: Icatibant Outcome Survey (NCT01034969) is an international observational registry monitoring the clinical outcomes of patients eligible for icatibant treatment. The current analyses are based on data collected between July 2009 and July 2019. Retrospective data for attacks recorded in the 12 months prior to IOS enrolment and for each 12-month period up to 7 years were analysed. RESULTS: Included patients reported angioedema attacks without long-term prophylaxis (LTP; n = 315) and with LTP (n = 292) use at the time of attack onset. Androgens were the most frequently used LTP option (80.8%). At the population level, regardless of LTP use, most patients (52-80%) reporting <5 attacks in Year 1 continued experiencing this rate; similarly, many patients (25-76%) who reported high attack frequency continued reporting ≥10 attacks/year. However, year on year, 31-51% of patients experienced notable changes (increase/decrease of ≥5 attacks) in annual attack frequency. Of patients who reported an absolute change of ≥10 attacks from Year 1 to 2, 17-50% continued to experience a change of this magnitude in subsequent years. CONCLUSION: At the population level, attack frequency was generally consistent over 7 years. At the small group level, 28.8-34.5% of patients reported a change in attack frequency of ≥5 attacks from Year 1 to Year 2; up to half of these patients continued to experience this magnitude of variation in disease activity in later years, reflecting high intra-patient variability.

Acquired angioedema in B cell lymphoproliferative disease: A retrospective case series.

Acquired angioedema due to C1-inhibitor (C1-INH) deficiency (AAE-C1-INH) is rare and is associated with underlying lymphoproliferative diseases. C1-INH deficiency may be due to neoplastic over-consumption of C1-INH and the generation of anti-C1-INH autoantibodies. Uncovering an occult malignancy can lead to earlier oncology referral and improvement of angioedema after treatment of the underlying lymphoproliferative disorder. We characterized seven patients with C1-INH-AAE that highlights the importance of recognizing the association between C1-INH-AAE and underlying malignancy. In acute attacks, patients may be resistant to C1-INH therapy due to the presence of anti-C1-INH autoantibodies or rapid complement consumption, and may respond better to icatibant or ecallantide, which directly affect bradykinin. Treatment of the underlying malignancy also improves AAE-C1-INH symptoms and supports the role of lymphoproliferative B cells in AAE-C1-INH pathophysiology. Monitoring levels of C4, C1-INH function and level, and C1q may be predictive of AAE-C1-INH control and be used as surrogates for treatment efficacy. With close monitoring, low-dose danazol can be effective for long-term prophylaxis. Annual evaluation in AAE-C1-INH is recommended if an underlying malignancy is not found, as angioedema may precede the development of malignancy by several years. Our single-center study has aided in standardization of comprehensive AAE-C1-INH diagnosis, treatment, and monitoring strategies towards future therapeutic clinical trials.

Blockade of the kinin B1 receptor counteracts the depressive-like behaviour and mechanical allodynia in ovariectomised mice.

Menopause is related to a decline in ovarian oestrogen production, affecting the perception of the somatosensory stimuli, changing the immune-inflammatory systems, and triggering depressive symptoms. It has been demonstrated that the inhibition of the kinin B1 and B2 receptors (B1R and B2R) prevented the depressive-like behaviour and the mechanical allodynia that was induced by immune-inflammatory mediators in mice. However, there is no evidence regarding the role of the kinin receptors in the depressive-like and nociceptive behaviour in female mice that were subjected to bilateral ovariectomy (OVX). This study has shown that the OVX mice developed time-related mechanical allodynia, together with an increased immobility time as indicative of depression. Both of these changes were reduced by the genetic deletion of B1R, or by the pharmacological blockade of the selective kinin B1R antagonist R-715 (acute, i.p.). The genetic deletion or the pharmacological inhibition of B2R (HOE 140, i.p.) did not prevent the OVX-elicited behavioural changes. The data has suggested a particular modulation of kinin B1R in the nociceptive and depressive-like behaviour in the OVX mice. The selective inhibition of the B1R receptor may be a new pharmacological target for treating pain and depression symptoms in women during the perimenopause/menopause period.

Activation of Galanin Receptor 1 with M617 Attenuates Neuronal Apoptosis via ERK/GSK-3ß/TIP60 Pathway After Subarachnoid Hemorrhage in Rats.

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular disease. Neuronal apoptosis plays an important pathological role in early brain injury after SAH. Galanin receptor 1 (GalR1) activation was recently shown to be anti-apoptotic in the setting of ischemic stroke. This study aimed to explore the anti-neuronal apoptosis effect of GalR1 activation after SAH, as well as the underlying mechanisms. GalR1 CRISPR and GalR1 selective agonist, M617, was administered, respectively. Extracellular-signal-regulated kinase (ERK) inhibitor (U0126) and glycogen synthase kinase 3-beta (GSK3-ß) CRISPR were administered to investigate the involvement of the ERK/GSK3-ß pathway in GalR1-mediated neuroprotection after SAH. Outcome assessments included neurobehavioral tests, western blot, and immunohistochemistry. The results showed that endogenous ligand galanin (Gal) and GalR1 were markedly increased in the ipsilateral brain hemisphere at 12 h and 24 h after SAH. GalR1 were expressed mainly in neurons, but expression was also observed in some astrocytes and microglia. GalR1 CRISPR knockdown exacerbated neurological deficits and neuronal apoptosis 24 h after SAH. Moreover, activation of GalR1 with M617 significantly improved short- and long-term neurological deficits but decreased neuronal apoptosis after SAH. Furthermore, GalR1 activation dysregulated the protein levels of phosphorylated ERK and GSK-3ß, but downregulated the phosphorylated Tat-interactive protein 60 (TIP60) and cleaved caspase-3 at 24 h after SAH. GalR1 CRISPR, U0126, and GSK-3ß CRISPR abolished the beneficial effects of GalR1 activation at 24 h after SAH in rats. Collectively, the present study demonstrated that activation of GalR1 using M617 attenuated neuronal apoptosis through the ERK/GSK-3ß/TIP60 pathway after SAH in rats. GalR1 may serve as a promising therapeutic target for SAH patients.