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To solve the "neutron lifetime puzzle," where measured neutron lifetimes differ depending on the measurement methods, an experiment with a pulsed neutron beam at J-PARC is in progress. In this experiment, neutrons are bunched into 40-cm lengths using a spin flip chopper (SFC), where the statistical sensitivity was limited by the aperture size of the SFC. The SFC comprises three sets of magnetic supermirrors and two resonant spin flippers. In this paper, we discuss an upgrade to enlarge the apertures of the SFC. With this upgrade, the statistics per unit time of the neutron lifetime experiment increased by a factor of 2.8, while maintaining a signal-to-noise ratio of 250–400, which is comparable to the previous one. Consequently, the time required to reach a precision of 1 s in the neutron lifetime experiment was reduced from 590 to 170 days, which is a significant reduction in time. This improvement in the statistics will also contribute to the reduction of systematic uncertainties, such as background evaluation, fostering further advancements in the neutron lifetime experiments at J-PARC. [ABSTRACT FROM AUTHOR]

An organized hematoma (OH) is a relatively rare benign lesion of the paranasal sinuses. Traditionally, it has been reported to occur following trauma, surgery, and sinus hemorrhagic lesions and in various bleeding predispositions. OHs are sometimes difficult to differentiate from malignancy because of the similar clinical symptoms and bone destruction. It is especially difficult when OHs occur in the same location as the primary tumor after treatment of a malignant tumor. In this paper, we report two cases of OH that occurred after intra-arterial chemoradiotherapy (IACRT) for maxillary sinus cancer. In one case, FDG accumulation was found in PET/CT and suspected to be a cancer recurrence. However, the postoperative pathology showed no malignant findings. This suggests that OH may show accumulation on 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET). In both cases, bleeding from the maxillary sinus continued after surgery. In one case, recurrence was observed, and in the other, nasal irrigation prevented the pooling of blood in the maxillary sinus, and no recurrence was observed. These cases suggest that OH after IACRT may easily recur because the bleeding continues even after surgery. In such cases, nasal irrigation or preoperative embolization may be helpful to avoid recurrence., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: Several scoring systems have been developed to predict prognosis in patients with refractory cancer. We aimed to validate eight scoring systems and determine the best method for predicting the prognosis of head and neck squamous cell carcinoma treated with nivolumab., Methods: This multicentre retrospective study involved 154 patients with recurrent and/or metastatic head and neck squamous cell carcinoma treated with nivolumab between 2017 and 2020. Oncological outcomes were assessed according to the scoring systems, including MD Anderson Cancer Center + neutrophil-to-lymphocyte ratio and Hammersmith scores. Objective response, overall survival and progression-free survival were evaluated using logistic regression and Cox proportional hazards analyses. Receiver operating curve analysis was used to calculate the area under the curve and estimate the efficacy of each score., Results: No significant associations were found between the responses and any score. Seven of the eight scoring systems were associated with disease control (odds ratio, 0.26-0.70). Amongst the eight scoring systems, MD Anderson Cancer Center + neutrophil-to-lymphocyte ratio showed the highest area under the curve for predicting response and disease control. Seven scoring systems were prognostic factors for progression-free survival (hazard ratio, 1.22-1.95). All eight scoring systems were prognostic factors for overall survival (hazard ratio, 1.62-3.83). According to the time-dependent receiver operating characteristics analysis for overall survival, the Hammersmith scoring system had the best predictive ability at 3 months, and the MD Anderson Cancer Center + neutrophil-to-lymphocyte ratio scoring system had the highest area under the curve between 6 and 24 months., Conclusions: MD Anderson Cancer Center + neutrophil-to-lymphocyte ratio and Hammersmith scoring systems were better predictors of prognosis in patients with head and neck squamous cell carcinoma treated with nivolumab., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Hypothermia develops during systemic anaphylaxis in rodents. The aim of this study was to elucidate the mechanism for the hypothermia by assessing the roles of locomotor activity, tail heat dissipation, heat production in the brown adipose tissue (BAT) activity, and chemical mediators during ovalbumin-induced anaphylactic hypotension in awake rats. We measured the core body temperature (T core ) and mean blood pressure (MBP), along with the surface temperature of the interscapular region (T iScap ), an indirect measure of BAT activity, and the tail (T tail ). During anaphylaxis, MBP decreased to the nadir of 53 ± 2 mmHg at 8 min with recovery toward baseline. T core began to decrease at 7.5 min with the nadir of 36.1 ± 0.2°C at 30 min from the baseline of 38.0 ± 0.1°C. T iScap also significantly decreased, but its onset was preceded by that of T core . T tail decreased after antigen, suggesting the absence of increased heat dissipation from the tail. The physical activity, as evaluated by moved distances, did not decrease until 20 min after antigen, followed by a progressive decrease. Reduced movement using a restraint maneuver not only reduced T core in nonsensitized rats but also augmented the anaphylactic hypothermia in the early phase (1.5-18 min) in sensitized rats. Combined antagonism against platelet-activating factor (PAF) and histamine H 1 receptors abolished antigen-induced hypotension but only attenuated hypothermia. In conclusion, decreased locomotor activity, but not tail heat dissipation or decreased BAT activity, may at least in part contribute to this hypothermia. PAF and histamine are involved mainly in hypotension but only partly in hypothermia during rat anaphylaxis. NEW & NOTEWORTHY Anaphylactic shock is a life-threatening systemic hypotension. Hypothermia is observed during systemic anaphylaxis of rats. We determined the mechanism as follows: decreased locomotor activity, but not tail heat dissipation or decreased BAT activity, may at least in part contribute to this hypothermia. PAF and histamine are involved mainly in hypotension, but only partly in hypothermia during rat anaphylaxis.

Background and Objective: Excessive prolongation of QT interval on ECGs in patients with congenital/acquired long QT syndrome and heart failure is a sign suggesting the development of early afterdepolarization (EAD), an abnormal repolarization in the action potential of ventricular cardiomyocytes. The development of EAD has been believed to be a trigger for fatal tachyarrhythmia, which can be a risk for sudden cardiac death. The role of EAD in triggering ventricular tachycardia (VT) remains unclear. The aim of this study was to elucidate the mechanism of EAD-induced triggered activity formation that leads to the VT such as Torsades de Pointes., Methods: We investigated the relationship between EAD and tachyarrhythmia initiation by constructing homogeneous myocardial sheet models consisting of the mid-myocardial cell version of a human ventricular myocyte model and performing simulations of excitation propagation., Results: A solitary island-like (clustering) occurrence of EADs in the homogeneous myocardial sheet could induce a focal excitation wave. However, reentrant excitation, an entity of tachyarrhythmia, was not able to be triggered regardless of the EAD cluster size when the focal excitation wave formed a repolarization potential difference boundary consisting of only a convex surface. The discontinuous distribution of multiple EAD clusters in the ventricular tissue formed a specific repolarization heterogeneity due to the repolarization potential difference, the shape of which depended on EAD cluster size and placed intervals. We found that the triggered activity was formed in such a manner that the repolarization potential difference boundary included a concave surface., Conclusions: The formation of triggered activity that led to tachyarrhythmia required not only the occurrence of EAD onset-mediated focal excitation wave but also a repolarization heterogeneity-based specific repolarization potential difference boundary shape formed within the tissue., Competing Interests: Declaration of Competing Interest The authors declare no competing interests., (Copyright © 2023. Published by Elsevier B.V.)

The immune system is known to be controlled by the autonomic nervous system including sympathetic and parasympathetic (vagus) nerves. C1 neurons in the medulla oblongata, which participate in the control of the autonomic nervous system, are responders to stressors and regulate the immune system. Short-term activation of C1 neurons suppresses inflammation, while the effect of a long-term activation of these neurons on the inflammatory reflex is unclear. We, herein, demonstrate that the coactivation of both the splenic sympathetic nerves and the adrenal gland adrenergic response are indispensable for the prognosis of acute lung injury. The chemogenetic activation of C1 neurons increased plasma catecholamine including adrenaline and noradrenaline levels. The deletion of catecholaminergic cells using local injections of viral vector in the adrenal gland abolished the protective effect against acute lung injury when the C1 neurons were stimulated by either chemogenetic or optogenetic tools. Furthermore, repeated activation of C1 neurons using chemogenetic tool inhibited the adrenal response without affecting the plasma noradrenaline levels, eliminated the protective effect against acute lung injury. This was rescued by the isoprenaline administration. We concluded that the maintenance of an adrenergic response via C1 neurons in the adrenal gland is a prerequisite for the delivery of an effective anti-inflammatory response., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The precise regulation of blood glucose levels is indispensable for maintaining physiological functions. C1 neurons determine the outflow of the autonomic nervous and endocrine systems to maintain blood glucose levels in the body. In contrast, activation of C1 neurons induces a decrease in activity, suggesting that hypoactivity also participates in maintaining blood glucose levels. To examine this, we evaluated both glycogenolysis and hypometabolism induced by the selective activation of C1 neurons. We used Dbh Cre/0 mice expressing receptors for chemogenetic tools in C1 neurons, resulting from microinjection of the viral vector. C1 neurons were activated by intraperitoneal injection of clozapine N-oxide (CNO). The chemogenetic activation of C1 neurons significantly decreased body temperature, oxygen consumption and carbon dioxide production. On the other hand, blood glucose levels were increased by activation of C1 neurons 2 h after CNO administration, even in the fasting state. In this situation, an increase in glucagon and corticosterone levels was observed, while hepatic glycogen content decreased significantly. Plasma insulin levels were not changed by the activation of C1 neurons despite the increase in blood glucose level. Furthermore, adrenal sympathetic nerve activity was significantly increased by the activation of C1 neurons, and plasma catecholamine levels increased significantly. In conclusion, the selective activation of C1 neurons using chemogenetic tools induced an increase in blood glucose levels, probably as a result of hepatic glycogenolysis and hypometabolism. KEY POINTS: Chemogenetic activation of C1 neurons in medulla oblongata decreased body temperature. Oxygen consumption and carbon dioxide production were decreased by chemogenetic activation of C1 neurons in medulla oblongata. Blood glucose levels were increased by chemogenetic activation of C1 neurons in medulla oblongata. Chemogenetic activation of C1 neurons in medulla oblongata increased glucagon, corticosterone and catecholamine levels in plasma. An increase in blood glucose levels by activation of C1 neurons occurred due to the combined effect of hepatic glycogenolysis and hypometabolism., (© 2023 The Authors. The Journal of Physiology © 2023 The Physiological Society.)

Inflammation associated with viral infection of the nervous system has been involved in the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease (AD) and multiple sclerosis. Polyinosinic:polycytidylic acid (poly[I:C]) is a Toll-like receptor 3 (TLR3) agonist that mimics the inflammatory response to systemic viral infections. Despite growing recognition of the role of glial cells in AD pathology, their involvement in the accumulation and clearance of amyloid β (Aβ) in the brain of patients with AD is poorly understood. Neprilysin (NEP) and insulin-degrading enzyme (IDE) are the main Aβ-degrading enzymes in the brain. This study investigated whether poly(I:C) regulated Aβ degradation and neurotoxicity by modulating NEP and IDE protein levels through TLR3 in astrocytes. To this aim, primary rat primary astrocyte cultures were treated with poly(I:C) and inhibitors of the TLR3 signaling. Protein levels were assessed by Western blot. Aβ toxicity to primary neurons was measured by lactate dehydrogenase release. Poly(I:C) induced a significant decrease in NEP levels on the membrane of astrocytes as well as in the culture medium. The degradation of exogenous Aβ was markedly delayed in poly(I:C)-treated astrocytes. This delay significantly increased the neurotoxicity of exogenous Aβ1-42. Altogether, these results suggest that viral infections induce Aβ neurotoxicity by decreasing NEP levels in astrocytes and consequently preventing Aβ degradation., (© 2022 International Society for Neurochemistry.)

Background: The identification of predictive factors is imperative for identifying patients with optimal responses to nivolumab. We aimed to determine whether body composition parameters can predict treatment outcomes in patients with head and neck squamous cell carcinoma (HNSCC) treated with nivolumab., Method: We performed a multicenter retrospective chart review of patients with recurrent and/or metastatic HNSCC treated with nivolumab between 2017 and 2020. Computed tomography images and anthropometric measures were used to determine the skeletal muscle index (SMI), subcutaneous adipose index, visceral adipose index (VAI), and body mass index. Objective response, overall survival (OS), progression-free survival (PFS), and severe immune-related adverse events (irAEs) were the main outcomes. Odds ratios (ORs) and hazard ratios (HRs) for low-index groups compared with high-index groups were calculated for these outcomes., Results: Our study comprised 114 patients with a median follow-up period of 23.1 months. Low SMI and low VAI were significantly associated with poor disease control [OR: 0.39, 95% confidence interval (CI): 0.15-0.97] and poor response (OR: 0.38, 95% CI: 0.15-0.94), respectively. Low SMI independently predicted poor OS (HR: 2.06, 95% CI: 1.16-3.67), poor PFS (HR: 1.74, 95% CI: 1.04-2.92), and increased incidence of irAEs (OR: 6.00, 95% CI: 1.04-34.61). Low VAI independently predicted poor PFS (HR 2.07, 95% CI: 1.15-3.73)., Conclusion: The SMI and VAI are predictive factors of nivolumab therapy in patients with HNSCC. Body composition indices should be assessed before nivolumab treatment for achieving optimal responses to nivolumab., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The autonomic nervous system, which consists of sympathetic and parasympathetic nerves, plays an important role in the regulation of various functions of body organs. Recent studies have reported that vagal afferents that transmit information from the periphery to the brain function as an important signal pathway for dissemination of details regarding nutritional status, as well as the cardiovascular system and inflammation. In this review, we describe the measurement analysis of vagal nerve activity in mice using an in vivo electrophysiological method and account for the role and mechanism of action of vagal nerves in homeostasis.

Idioblasts are defined by abnormal shapes, sizes, and contents that are different from neighboring cells. Myrosin cells are Brassicales-specific idioblasts and accumulate a large amount of thioglucoside glucohydrolases (TGGs, also known as myrosinases) in their vacuoles. Myrosinases convert their substrates, glucosinolates, into toxic compounds when herbivories and pests attack plants. In this review, we highlight the similarities and differences between myrosin cells and vascular cells/guard cells (GCs) because myrosin cells are distributed along vascular cells, especially the phloem parenchyma, and myrosin cells share the master transcription factor FAMA with GCs for their cell differentiation. In addition, we analyzed the overlap of cell type-specific genes between myrosin cells and GCs by using published single-cell transcriptomics (scRNA-seq) data, suggesting significant similarities in the gene expression patterns of these two specialized cells., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Shirakawa, Tanida and Ito.)

The pathology of sporadic Alzheimer's disease is hallmarked by altered signal transduction via the neurotransmitter receptor-G-protein-mediated protein kinase A (PKA) and protein kinase C (PKC) pathways. Because the accumulation of amyloid-β (Aβ) depends on its rates of synthesis and clearance, the metabolic pathway of Aβ in the brain and the entire body warrants exploration. The two major enzymes involved in Aβ degradation in the brain are believed to be the neprilysin and insulin-degrading enzyme (IDE). This study investigated whether PKA and PKC regulate the degradation of Aβ by modulating the protein levels of neprilysin and IDE in astrocytes. Activation of PKA induced a significant decrease in neprilysin protein levels in cultured astrocytes, whereas activation of PKC induced a significant decrease in the protein level of neprilysin and an increase in the protein level of IDE. Following activation of PKC, the reduction of neprilysin was achieved by its secretion into the culture media. Moreover, PKA-activated astrocytes significantly delayed the degradation of exogenous Aβ, whereas PKC-activated astrocytes significantly facilitated its degradation. These results suggest that PKA and PKC regulate Aβ degradation in astrocytes through a decrease in the protein level of neprilysin and an increase in neprilysin secretion and protein levels of IDE, respectively., Competing Interests: Declaration of Competing Interest The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (Copyright © 2020 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.)

Angiopoietin (Angpt)-2, a permeability-increasing growth factor, is involved in vascular leakage of sepsis and acute lung injury, and could be released from endothelium in response to anaphylaxis-related secretagogues such as histamine and leukotrienes, or cytokines. However, roles of Angpt-2 in the hyperpermeability during systemic anaphylaxis are not known. Thus, we determined plasma levels of Angpt-2 and cytokines and vascular permeability during anaphylactic hypotension in unanesthetized rats. Anaphylaxis was induced by an intravenous injection of ovalbumin antigen. Mean arterial blood pressure (MBP) was measured, and hematocrit (Hct) and plasma levels of Angpt-2 and cytokines were assessed for 24 h after antigen injection. Separately, vascular permeability was measured in various organs using the Evans blue dye method, and Angpt-2 mRNA expression in liver was measured. After antigen injection, MBP decreased to the nadir at 6 min, and returned to baseline at 45 min, and Hct peaked at 20 min and thereafter progressively declined, suggesting that vascular leak and hypotension occurred within 20 min. Plasma Angpt-2 levels began to increase significantly at 1 h after antigen, reaching the peak 2.7-fold baseline at 6 h with a return to baseline at 24 h. Detected cytokines of IL-1α, IL-1β, IL-6, IL-10, and TNF-α peaked 1 or 2 h after antigen. Angpt-2 mRNA increased at 2 h and showed an increasing tendency at 6 h. Vascular permeability in bronchus, trachea, intestines, mesentery and skeletal muscle was increased at 10 min but not at 6 h after antigen. In addition, we confirmed using anesthetized rat anaphylaxis models that plasma Angpt-2 levels increased at 1 h after antigen. In conclusion, plasma Angpt-2 is elevated presumably due to increased cytokines and enhanced gene transcription during anaphylaxis in anesthetized and unanesthetized rats., Competing Interests: The authors have declared that no competing interests exist.

Recent clinical and experimental evidence has evoked the concept of the gut-brain axis to explain mutual interactions between the central nervous system and gut microbiota that are closely associated with the bidirectional effects of inflammatory bowel disease and central nervous system disorders 1-4 . Despite recent advances in our understanding of neuroimmune interactions, it remains unclear how the gut and brain communicate to maintain gut immune homeostasis, including in the induction and maintenance of peripheral regulatory T cells (pT reg cells), and what environmental cues prompt the host to protect itself from development of inflammatory bowel diseases. Here we report a liver-brain-gut neural arc that ensures the proper differentiation and maintenance of pT reg cells in the gut. The hepatic vagal sensory afferent nerves are responsible for indirectly sensing the gut microenvironment and relaying the sensory inputs to the nucleus tractus solitarius of the brainstem, and ultimately to the vagal parasympathetic nerves and enteric neurons. Surgical and chemical perturbation of the vagal sensory afferents at the hepatic afferent level reduced the abundance of colonic pT reg cells; this was attributed to decreased aldehyde dehydrogenase (ALDH) expression and retinoic acid synthesis by intestinal antigen-presenting cells. Activation of muscarinic acetylcholine receptors directly induced ALDH gene expression in both human and mouse colonic antigen-presenting cells, whereas genetic ablation of these receptors abolished the stimulation of antigen-presenting cells in vitro. Disruption of left vagal sensory afferents from the liver to the brainstem in mouse models of colitis reduced the colonic pT reg cell pool, resulting in increased susceptibility to colitis. These results demonstrate that the novel vago-vagal liver-brain-gut reflex arc controls the number of pT reg cells and maintains gut homeostasis. Intervention in this autonomic feedback feedforward system could help in the development of therapeutic strategies to treat or prevent immunological disorders of the gut.

Early afterdepolarization (EAD) is known to cause lethal ventricular arrhythmias in long QT syndrome (LQTS). In this study, dynamical mechanisms of EAD formation in human ventricular myocytes (HVMs) were investigated using the mathematical model developed by ten Tusscher and Panfilov ( Am J Physiol Heart Circ Physiol 291, 2006). We explored how the rapid (I Kr ) and slow (I Ks ) components of delayed-rectifier K + channel currents, L-type Ca 2+ channel current (I Ca L ), Na + /Ca 2+ exchanger current (I NCX ), and intracellular Ca 2+ handling via the sarcoplasmic reticulum (SR) contribute to initiation, termination and modulation of phase-2 EADs during pacing in relation to bifurcation phenomena in non-paced model cells. Parameter-dependent dynamical behaviors of the non-paced model cell were determined by calculating stabilities of equilibrium points (EPs) and limit cycles, and bifurcation points to construct bifurcation diagrams. Action potentials (APs) and EADs during pacing were reproduced by numerical simulations for constructing phase diagrams of the paced model cell dynamics. Results are summarized as follows: (1) A modified version of the ten Tusscher-Panfilov model with accelerated I CaL inactivation could reproduce bradycardia-related EADs in LQTS type 2 and β-adrenergic stimulation-induced EADs in LQTS type 1. (2) Two types of EADs with different initiation mechanisms, I CaL reactivation-dependent and spontaneous SR Ca 2+ release-mediated EADs, were detected. (3) Termination of EADs (AP repolarization) during pacing depended on the slow activation of I Ks . (4) Spontaneous SR Ca 2+ releases occurred at higher Ca 2+ uptake rates, attributable to the instability of steady-state intracellular Ca 2+ concentrations. Dynamical mechanisms of EAD formation and termination in the paced model cell are closely related to stability changes (bifurcations) in dynamical behaviors of the non-paced model cell, but they are model-dependent. Nevertheless, the modified ten Tusscher-Panfilov model would be useful for systematically investigating possible dynamical mechanisms of EAD-related arrhythmias in LQTS., (Copyright © 2020 Kurata, Tsumoto, Hayashi, Hisatome, Kuda and Tanida.)

Background/aim: Leptin, one of the hormones produced in white adipose tissue, is an efferent sympathetic stimulator. Actually, an injection of leptin into the brain has been shown to activate sympathetic nerve activities innervating the kidney, adrenal gland, adipose tissues, liver, and lumbar in rats., Materials and Methods: This study investigated the effects of an intracerebroventricular injection of leptin on the activities of sympathetic nerves innervating the stomach and spleen in anesthetized rats., Results: Leptin injection activated the neural activities of sympathetic traffic to both the stomach and spleen. In addition, to investigate the role of AMP-activated protein kinase (AMPK), the effects of 5-aminoimidazole-4-carboxamide 1-beta-D-ribofuranoside (AICAR), an AMPK activator, or compound C, an AMPK inhibitor, on leptin-induced sympathoexcitation, were assessed. Central pretreatment with AICAR or compound C eliminated not only leptin-induced gastric sympathoexcitation but also leptin-induced splenic sympathoexcitation., Conclusion: Leptin stimulates efferent sympathetic outflow to the stomach and spleen through the hypothalamic AMPK., (Copyright© 2019, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Diarrhea is a gastrointestinal symptom associated with systemic anaphylaxis and could be induced by increased colonic motility. We determined colonic motility and expulsion by measuring the intracolonic pressure (ICP) and expelled fluid weight in anesthetized rats during anaphylactic hypotension. Substantial systemic hypotension occurred in every sensitized rat after antigen injection. One min after antigen injection, ICP began to increase and remained elevated for 5 min, which was revealed to represent tonic contraction by the video-recording procedure, and was accompanied by increased colonic fluid expulsion. Parasympathectomy composed of subdiaphragmatic vagotomy combined with pelvic nerve transection reduced the duration of the tonic contraction, but not expelled colonic fluid. Furthermore, denervation of afferent parasympathetic nerves produced essentially the same effect as parasympathectomy. Sympathectomy did not significantly change any parameters. In conclusion, the colonic motility during anaphylactic hypotension is characterized by 5-min lasting tonic contraction which is associated with increased colonic fluid expulsion and is involved by parasympathetic nerves, especially their afferents, but not sympathetic nerves, in anesthetized rats.

Systemic anaphylaxis is a life-threatening and allergic reaction that affects various organs. We previously reported that, in the stomach, gastric vasoconstriction occurring at the late phase (15-55 min after injection of ovalbumin antigen) was observed in anesthetized rats sensitized with ovalbumin. In addition, anaphylaxis enhances gastric motility and delays emptying. However, the role of extrinsic autonomic nervous system on antigen-induced gastric alterations was not known. Thus, using the same rat anaphylaxis model, we aimed to determine the changes in the efferent and afferent autonomic nerve activities in the stomach during anaphylactic hypotension. The findings showed that injection of ovalbumin antigen caused substantial systemic hypotension in all sensitized rats. The efferent gastric sympathetic nerve activity (ef-GSNA), but not the efferent vagal nerve activity, increased only at the early phase (1-10 min after injection of ovalbumin antigen) and showed baroreceptor reflex, as evidenced by a stimulatory response to sodium nitroprusside-induced hypotension. In general, excitation of ef-GSNA could induce pylorus sphincter contraction and gastric vasoconstriction. In the present study, we found that sympathectomy attenuated the anaphylaxis-induced decrease in gastric flux but not the increase in gastric vascular resistance. Thus, the increase in ef-GSNA may cause anaphylactic pylorus sphincter contraction but not anaphylactic gastric vasoconstriction. On the other hand, the afferent gastric vagal nerve activity, but not the afferent sympathetic nerve activity, increased during the early phase of anaphylactic hypotension. However, vagotomy produced no effects on the anaphylactic gastric dysfunction. In conclusion, the gastric sympathetic nerves partly modulate stomach function during systemic anaphylaxis.