[Efficacy of hepatitis B immunoprophylaxis in children at high risk of hepatitis B and risk factors for mother-to-child transmission of hepatitis B virus].

OBJECTIVE: To investigate the risk factors for mother-to-child transmission of hepatitis B virus (HBV) and the efficacy of hepatitis B immunoprophylaxis in children at high risk of hepatitis B. METHODS: A questionnaire survey was performed on 539 HBsAg-positive mothers and their 551 children (aged from 6 months to 5 years) at high risk of hepatitis B. Serum markers of hepatitis B in the children at high risk of hepatitis B were measured. Univariate logistic regression analysis was used to investigate the risk factors for mother-to-child transmission of HBV. RESULTS: The rate of hepatitis B vaccination in the children at high risk of hepatitis B was 100%, and 96.6% received injections of hepatitis B vaccine and hepatitis B immunoglobulin (HBIG). The HBsAg positive rate showed no significant differences between different age groups. The HBsAb positive rate gradually decreased with the increasing age (P<0.01). The children born to HBsAg- and HBeAg-positive mothers had a significantly higher hepatitis B infection rate than those born to HBsAg-positive mothers (15.1% vs 0.2%; P<0.01). The high-risk children who received hepatitis B vaccination alone had a significantly higher hepatitis B infection rate than those who received both hepatitis B vaccine and HBIG injections (28.6% vs 2.8%; P<0.01). CONCLUSIONS: The HBsAb positive rate gradually decreases with the increasing age in children at high risk of hepatitis B. Maternal HBsAg and HBeAg positivity and the absence of HBIG combined with hepatitis B vaccine injections for children at high risk of hepatitis B are the risk factors for mother-to-child transmission of HBV.

Corrigendum to "Study of hydrosalpinx on endometrial growth and expression of HOXA10mRNA and related factors" [Heliyon 9(6) (June 2023) e17063].

[This corrects the article DOI: 10.1016/j.heliyon.2023.e17063.].

Study of hydrosalpinx on endometrial growth and expression of HOXA10mRNA and related factors.

Objective: The objective of the study is to extract the patient's endometrium at the time of proliferative stage using hydrosalpinx in order to culture the cells and decidualization induction in vitro. Further, the study is also intended at identifying the expression of HOXA10mRNA and related factors and understand the hydrosalpinx's impact upon the working mechanism of endometrial cells. Methods: Once the extraction of the primary cells is over, the cells are cultured and other activities are performed such as the cell identification, CCK8 assay, cell decidua induction and HE staining. The researchers assessed the expression levels of HOXA10, IGFBP1 and avß3 in either proliferation or secretion of the endometrium. This was accomplished using Western blot assay and real-time fluorescence quantitative PCR. Results: The results confirmed that at the time of endometrial proliferation, there was a decline in the expression of HOXA10 as a result of tubal effusion influence. This affected its expression in the secretory stage i.e., corresponding function. Further, a significant decline was observed in the levels of HOXA10mRNA of endometrial cells that were subjected to continuous tubal effusion, post decidualization. It was found that during decidualization, if thetubal effusion is removed, it is possible to restore the expression of HOXA10mRNA to a certain extent, though it is not possible to reach the general endometrial level. So, in terms of clinical aspects, the expression of HOxa10 mRNA by the endometrial cells decreases significantly when blocking the hydrosalpinx. Conclusions: Among hydrosalpinx patients, one of the major mechanisms that damage the endometrium was found to be the abnormal expression of HOXA10 followed by IGFBP1 and avß3, its downstream genes. This further results in the implantation of the embryo as well. Though it is possible to gradually repair the damage after the removal of hydrosalpinx, the recovery is a time-consuming process.

Subtle alterations of vestibulomotor functioning in conductive hearing loss.

Introduction: Conductive hearing loss (CHL) attenuates the ability to transmit air conducted sounds to the ear. In humans, severe hearing loss is often accompanied by alterations to other neural systems, such as the vestibular system; however, the inter-relations are not well understood. The overall goal of this study was to assess vestibular-related functioning proxies in a rat CHL model. Methods: Male Sprague-Dawley rats (N=134, 250g, 2months old) were used in a CHL model which produced a >20dB threshold shift induced by tympanic membrane puncture. Auditory brainstem response (ABRs) recordings were used to determine threshold depth at different times before and after CHL. ABR threshold depths were assessed both manually and by an automated ABR machine learning algorithm. Vestibular-related functioning proxy assessment was performed using the rotarod, balance beam, elevator vertical motion (EVM) and Ferris-wheel rotation (FWR) assays. Results: The Pre-CHL (control) threshold depth was 27.92dB±11.58dB compared to the Post-CHL threshold depth of 50.69dB±13.98dB (mean±SD) across the frequencies tested. The automated ABR machine learning algorithm determined the following threshold depths: Pre-CHL=24.3dB, Post-CHL same day=56dB, Post-CHL 7 days=41.16dB, and Post-CHL 1 month=32.5dB across the frequencies assessed (1, 2, 4, 8, 16, and 32kHz). Rotarod assessment of motor function was not significantly different between pre and post-CHL (~1week) rats for time duration (sec) or speed (RPM), albeit the former had a small effect size difference. Balance beam time to transverse was significantly longer for post-CHL rats, likely indicating a change in motor coordination. Further, failure to cross was only noted for CHL rats. The defection count was significantly reduced for CHL rats compared to control rats following FWR, but not EVM. The total distance traveled during open-field examination after EVM was significantly different between control and CHL rats, but not for FWR. The EVM is associated with linear acceleration (acting in the vertical plane: up-down) stimulating the saccule, while the FWR is associated with angular acceleration (centrifugal rotation about a circular axis) stimulating both otolith organs and semicircular canals; therefore, the difference in results could reflect the specific vestibular-organ functional role. Discussion: Less movement (EVM) and increase time to transverse (balance beam) may be associated with anxiety and alterations to defecation patterns (FWR) may result from autonomic disturbances due to the impact of hearing loss. In this regard, vestibulomotor deficits resulting in changes in balance and motion could be attributed to comodulation of auditory and vestibular functioning. Future studies should manipulate vestibular functioning directly in rats with CHL.

Profiling of cybersickness and balance disturbance induced by virtual ship motion immersion combined with galvanic vestibular stimulation.

Profile of cybersickness and balance disturbance induced by virtual ship motion alone and in combination with galvanic vestibular stimulation (GVS) remained unclear. Subjects were exposed to a ship deck vision scene under simulated Degree 5 or 3 sea condition using a head-mounted virtual reality display with or without GVS. Virtual ship motion at Degree 5 induced significant cybersickness with symptom profile: nausea syndrome > central (headache and dizziness) > peripheral (cold sweating) > increased salivation. During a single session of virtual ship motion exposure, GVS aggravated balance disturbance but did not affect most cybersickness symptoms except cold sweating. Repeated exposure induced cybersickness habituation which was delayed by GVS, while the temporal change of balance disturbance was unaffected. These results suggested that vestibular inputs play different roles in cybersickness and balance disturbance during virtual reality exposure. GVS might not serve as a potential countermeasure against cybersickness induced by virtual ship motion.

Sea Voyage Training and Motion Sickness Effects on Working Ability and Life Quality After Landing.

BACKGROUND: The effects of seasickness on working performance during motion exposure have been reported, while the aftereffects on working ability and life quality decline (WLD) still remain unclarified.METHODS: Two cohorts of healthy male Chinese subjects received either a single (SSV) or repeated (RSV) sea voyage training program on different vessels. A seasickness incidence (SSI) questionnaire was administered to assess the prevalence of seasickness symptoms (vomiting, nausea, other, or no symptoms). A WLD questionnaire was used to survey the general feeling of WLD (severe, moderate, slight, and none) by a 4-point score as well as the incidence rate (IR) of specific WLD items within 24 h after landing.RESULTS: The RSV cohort had lower overall IR of WLD than the SSV cohort (54.64% vs. 63.78%, N 657 for both cohorts). The landing ship trainees in both cohorts showed higher general WLD score and higher IRs of physical fatigue, sleep disorder, and spontaneous locomotion decrement than those trained on the small vessels. Subjects with vomiting or nausea had higher general WLD score and higher IRs of concentration distraction, physical fatigue, anorexia, and spontaneous locomotion decrement than those with no symptoms. Higher IRs of firing accuracy decline (SSV: 21.35% vs. 7.13%, 9.14%; RSV: 22.11% vs. 9.28%, 5.27%), equipment operation disturbance (SSV: 16.85% vs. 3.57%, 6.85%; RSV: 20.47% vs. 7.85%, 7.03%) were also observed in the vomiting subjects than those with other symptoms and no symptoms.DISCUSSION: Significant WLD after landing was associated with transportation types, seasickness severity, and habituation during sea voyage training.Qi R-R, Xiao S-F, Su Y, Mao Y-Q, Pan L-L, Li C-H, Lu Y-L, Wang J-Q, Cai Y-L. Sea voyage training and motion sickness effects on working ability and life quality after landing. Aerosp Med Hum Perform. 2021; 92(2):9298.

Military Trauma and Surgical Procedures in Conflict Area: A Review for the Utilization of Forward Surgical Team.

Introduction: Forward surgical teams (FSTs) have been used as highly mobile surgical facilities that provide "damage control" medical support in modern wars. FST regiments differ greatly in different armed services and nations. We systemically reviewed the utilization of FSTs around the world with an emphasis on the medical conditions and workloads encountered by FSTs in modern wars. Materials and Methods: We searched for terms related to FSTs, such as "Forward Surgical Team" and "Field Surgical Team," in the PubMed, EMBASE, Web of Science, and MEDLINE databases and collected any articles that provided numerical data on the organization of medical personnel combat casualty characteristics, including the casualty composition, injury types and locations, and mechanisms of injury, and surgical procedures performed. Technical articles, case reports of specific types of injury or disease, and literature reviews of previous experiences and logistical theories were discarded. Results: We identified 24 articles involving 29 FSTs that were included in the analysis. The FSTs were typically composed of 8-20 medical personnel and had limited medical capacity. Battle-related injuries constituted approximately two-thirds of all injury types treated by the FSTs. The extremities, torso, and head and neck were the three most frequently injured sites and accounted for approximately 51.1%, 16.6%, and 13.2% of all wounds, respectively. The three most frequent injury mechanisms were fragments or explosive injuries (44.8%), gunshot wounds (28.1%), and motor vehicle accidents/road traffic accidents (9.1%). Soft tissue surgeries (41.0%) and orthopedic operations (31.6%) were the two procedures that were most frequently performed by the FSTs. The average numbers of surgical procedures performed by small FSTs (1.27/unit·day) and full FSTs (1.28/unit·day) seemed to be comparable. Conclusion: Modern conflict may require more flexible small FSTs, especially during the initial phases of war. More orthopedic surgeons should be included in FSTs, and orthopedic skill training should be intensified before deployment. The utilization of FSTs and level III facilities must be evaluated within the context of the battlefield conditions, medical care requirements, and evacuation efficiency.

Glutamatergic vestibular neurons express Fos after vestibular stimulation and project to the NTS and the PBN in rats.

In this study, retrograde tracing method combined with phosphate-activated glutaminase (PAG) and Fos immunofluorescence histochemistry was used to identify glutamatergic vestibular nucleus (VN) neurons receiving vestibular inputs and projecting to the nucleus of the solitary tract (NTS) and the parabrachial nucleus (PBN). Conscious animals were subjected to 120 min Ferris-wheel like rotation stimulation. Neuronal activation was assessed by Fos expression in the nucleus of VN neurons. After Fluoro-gold (FG) injection into the caudal NTS, approximately 48% FG-labeled VN neurons were immunoreactive for PAG, and about 14% PAG/FG double-labeled neurons co-existed with Fos. Following FG injection into the PBN, approximately 56% FG-labeled VN neurons were double-labeled with PAG, and about 12% of the PAG/FG double-labeled neurons also expressed Fos. Careful examination of the typology and distribution pattern of these PAG-immunoreactive neurons indicated that the vast majority of these neurons were glutamatergic rather than GABAergic. These results suggest that PAG-immunoreactive VN neurons might constitute excitatory glutamatergic VN-NTS and VN-PBN transmission pathways and these pathways might be involved in vestibulo-autonomic reflexes during vestibular stimulation.

Motion Sickness and Resting Energy Expenditure in Chinese Male Adults.

BACKGROUND: Motion sickness can influence energy homeostasis by enhancing thermolysis. This study tested the hypothesis that resting energy expenditure (REE), as the major component of thermogenesis, might also play a role during motion sickness. METHODS: The effect of seasickness on REE at sea was examined in 71 healthy Chinese male volunteers. Change in REE, heart rate variability (HRV), blood ghrelin levels, and leptin levels were observed across baseline, voyage, and recovery stages. Seasickness severity was assessed using the Graybiel motion sickness questionnaire (GMSQ), and the nausea syndrome rating (NSR) of each participant was also evaluated. REE was examined by indirect calorimetry. HRV was derived from the electrocardiogram to analyze cardiac sympathovagal activity. Blood ghrelin and leptin levels were tested by radioimmunoassay. RESULTS: In subjects with severe seasickness during the voyage, the GMSQ and NSR scores were higher than in subjects with slight and moderate seasickness. The REE declined significantly compared to baseline and recovery levels and was lower than in subjects with slight and moderate seasickness. Cardiac sympathetic activity was significantly decreased, while vagal activity was increased. Plasma ghrelin levels were also significantly increased and were negatively correlated with the measured REE levels and positively correlated with NSR as well as change of HRV LF/HF ratio from baseline. DISCUSSION: Severe motion sickness induces REE suppression, which may be attributed to dramatic alteration of sympathovagal activity and plasma ghrelin levels in humans.

Motion Sickness: Current Knowledge and Recent Advance.

Motion sickness (MS) is a common physiological response to real or virtual motion. Numerous studies have investigated the neurobiological mechanism and the control measures of MS. This review summarizes the current knowledge about pathogenesis and pathophysiology, prediction, evaluation, and countermeasures of MS. The sensory conflict hypothesis is the most widely accepted theory for MS. Both the hippocampus and vestibular cortex might play a role in forming internal model. The pathophysiology focuses on the visceral afference, thermoregulation and MS-related neuroendocrine. Single-nucleotide polymorphisms (SNPs) in some genes and epigenetic modulation might contribute to MS susceptibility and habituation. Questionnaires, heart rate variability (HRV) and electrogastrogram (EGG) are useful for diagnosing and evaluating MS. We also list MS medications to guide clinical practice. Repeated real motion exposure and combined visual-vestibular interaction training accelerate the progress of habituation. Behavioral and dietary countermeasures, as well as physiotherapy, are also effective in alleviating MS symptoms.

Calbindin D28k-containing neurons in the paratrigeminal nucleus receive convergent nociceptive information and project to nucleus of the solitary tract in rat.

The paratrigeminal nucleus (PTN) receives orofacial somatic and visceral afferent fibers and contains many calbindin-D28k neurons (CB-containing neurons) that project to nucleus of the solitary tract (NTS). In the present study, retrograde and transganglionic tracing methods combined with immunofluorescence histochemistry and confocal laser scanning microscopy were used. After Fluoro-gold (FG) injection into the unilateral NTS, 74.4% FG-labeled neurons of ipsilateral PTN were double-labeled with CB. Furthermore, 41.0% and 32.5% FG/CB double-labeled neurons co-existed with Fos induced by nociceptive stimulation of the lips and the upper alimentary tract, respectively. In the PTN unilateral to FG injection site, 26.6% CB-LI neurons were double-labeled with PAG, 61.5% and 79.0% CB/PAG double-labeled neurons were triple-labeled with FG and Fos, and 22.9% FG/CB double-labeled neurons were triple-labeled with PAG, 84.3% FG/PAG double-labeled neurons expressed Fos induced by the upper alimentary tract stimulation. In the intact animals, 62.8% CB-LI neurons and 88.3% PAG-LI neurons co-existed with GABA(B)R, respectively. In addition, some terminals from the inferior alveolar nerve (IAN) were closely apposed to CB/Fos double-labeled or CB single-labeled neurons. These results suggested that CB-containing neurons in the PTN receive the nociceptive information converge from the orofacial area and visceral organs, and comprising the glutamatergic excitatory transmission pathway from the PTN to the NTS. This pathway might be modulated by GABA via the GABA(B) receptor.

[Behavioral changes of rats under rotation stimulation].

OBJECTIVE: To assess the specification and efficiency of rotation sickness indices by monitoring changes of behaviors in rats under rotation stimulation. METHOD: SD rats were stimulated by Crampton model with different time courses. Pica or kaolin consumption (KC), conditioned taste aversion (CTA) or saccharine water ingestion (SWI), 2 h food ingestion (2hFI), and open-field test (OFT) scores were observed. RESULT: Apparent changes of the four indices were observed after rotation stimulation. SWI, OFT scores and 2hFI decreased exponentially with increase of duration of the motion stimulation. KC increased linearly with the increase of time within 12 h stimulation. After 18 h stimulation, KC decreased to a level even lower than that after 6 or 12 h stimulation. The adjusted correlation between changes of the indices and duration of stimulation within 12 h are: 0.94 for KC, 0.54 for SWI, 0.44 for 2hFI and 0.34 for OFT. The maximum efficiency of the four indices appeared at 6-hour stimulation: 70% for KC, 90% for SWI, 80% for 2hFI and 95% for OFT. CONCLUSION: It is found that pica and CTA were more specific than the other indices. They may serve as primary indices and can be combined with the secondary indices such as 2hFI or OFT. Six hours is the optimal duration of stimulation by Crampton model for rotation sickness studies.

Differential Gene Expression Profile in the Rat Caudal Vestibular Nucleus is Associated with Individual Differences in Motion Sickness Susceptibility.

OBJECTIVE: To identify differentially expressed genes associated with motion sickness (MS) susceptibility in the rat caudal vestibular nucleus. METHODS: We identified MS susceptible (MSS) and insusceptible (inMSS) rats by quantifying rotation-induced MS symptoms: defecation and spontaneous locomotion activity. Microarray analysis was used to screen differentially expressed genes in the caudal vestibular nucleus (CVN) after rotation. Plasma stress hormones were identified by radioimmunoassay. Candidate genes were selected by bioinformatics analysis and the microarray results were verified by real-time quantitative-PCR (RT-qPCR) methods. By using Elvax implantation, receptor antagonists or recombinant adenovirus targeting the candidate genes were applied to the CVN to evaluate their contribution to MS susceptibility variability. Validity of gene expression manipulation was verified by RT-qPCR and western blot analysis. RESULTS: A total of 304 transcripts were differentially expressed in the MSS group compared with the inMSS group. RT-qPCR analysis verified the expression pattern of candidate genes, including nicotinic cholinergic receptor (nAchR) α3 subunit, 5-hydroxytryptamine receptor 4 (5-HT4R), tachykinin neurokinin-1 (NK1R), γ-aminobutyric acid A receptor (GABAAR) α6 subunit, olfactory receptor 81 (Olr81) and homology 2 domain-containing transforming protein 1 (Shc1). In MSS animals, the nAchR antagonist mecamylamine significantly alleviated rotation-induced MS symptoms and the plasma ß-endorphin response. The NK1R antagonist CP99994 and Olr81 knock-down were effective for the defecation response, while the 5-HT4R antagonist RS39604 and Shc1 over-expression showed no therapeutic effect. In inMSS animals, rotation-induced changes in spontaneous locomotion activity and the plasma ß-endorphin level occurred in the presence of the GABAAR antagonist gabazine. CONCLUSION: Our findings suggested that the variability of the CVN gene expression profile after motion stimulation might be a putative molecular basis for individual differences in MS susceptibility and provide information for the development of new therapeutic strategies for MSS individuals.

Temporal change in NMDA receptor signaling and GABAA receptor expression in rat caudal vestibular nucleus during motion sickness habituation.

Repeated exposure to a provocative motion stimulus leads to motion sickness habituation indicative of the existence of central processes to counteract the disturbing properties of the imposed motion. In the present study, we attempt to investigate whether NMDA and GABA(A) receptors in rat caudal vestibular nucleus neurons are involved in motion sickness habituation induced by repeated Ferris-wheel like rotation in daily session (2h/d). We showed that defecation response increased and spontaneous locomotion decreased within 4 sessions (sickness phase). They recovered back to the control level after 7 sessions (habituation phase). Western blot analysis found that NMDA receptor signal molecules: calmodulin protein kinase II and cAMP response element-binding protein (CREB) were both activated during sickness phase, while a prolonged CREB activation was also observed during habituation phase. Real-time quantitative PCR revealed an increase in c-fos and a decrease in Arc mRNA level during sickness phase. We also found an increase in GABA(A) receptor α1 subunit (GABA(A) α1) protein level in this stage. These results suggested that altered NMDA receptor signaling and GABA(A) receptor expression level in caudal vestibular nucleus were associated with motion sickness habituation. Furthermore, immunofluorescence and confocal laser scanning microscopy showed that the number of GABA(A) α1 immunolabeled neurons in caudal vestibular nucleus increased while the number of GABA(A) α1/Arc double labeled neurons and the average amount of Arc particle in soma of these neurons decreased during sickness phase. It suggested that GABA(A) receptor level might be negatively regulated by Arc protein in caudal vestibular nucleus neurons.

Acute hyperglycemia is related to gastrointestinal symptoms in motion sickness: an experimental study.

Motion sickness is caused by exposure to unfamiliar motions and typical symptoms of motion sickness include nausea and vomiting. To observe the metabolic and hormonal differences between nausea/vomiting (NAV) subjects and non-nausea/vomiting (NNV) ones, and to understand how the differences in metabolites and hormones affect the tolerance of organism to acceleration, 60 volunteers were exposed to repetitive acceleration using a 6-degree-of-freedom ship motion simulator. Meanwhile, 36 rats were randomly divided into three groups: an acceleration model group (n=14, exposed to acceleration), insulin group (n=14, intraperitoneal injection of insulin 30 min before exposure to acceleration), and control group (n=8). Gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF/MS) was applied to analyze the serum metabolites in human subjects. Serum glucocorticoid, insulin, and glucagon levels were determined by radioimmunoassay in the NAV and NNV subjects as well as in rats, and serum epinephrine level was determined by ELISA. After acceleration exposure, 9 metabolites, including L-histidine, L-ornithine, L-serine, L-tyrosine, pyroglutamic acid, fumaric acid, urea, n-dodecanoic acid and n-tetradecanoic acid, had different changes in the NAV and NNV groups. The serum levels of 4-hydroxy-L-proline, glucose, oleic acid and urea were significantly higher in the NAV group than in the NNV group after exposure; however, only the elevation degree of serum glucose was significantly greater in the NAV group than in the NNV group (P<0.05). Serum cortisol and epinephrine were increased in both groups. Before exposure, insulin level in the NAV group was significantly lower than that in the NNV group (P<0.05). After rotation exposure, rat serum glucose in the insulin group was significantly lower than that in the acceleration model group (P<0.001), and the motion sickness index was significantly lower than that in the acceleration model group (P<0.05). Our study provides the first evidence that stable glucose level can help to relieve gastrointestinal symptoms in motion sickness, and suggests that acute hyperglycemia is related to gastrointestinal symptoms in motion sickness.

Decreased Fos protein expression in rat caudal vestibular nucleus is associated with motion sickness habituation.

We investigated the temporal change of Fos protein expression in the caudal vestibular nucleus of rats exposed to daily 2-h Ferris-wheel like (FWL) rotation. Repeated rotation (2h daily for 14 consecutive days) caused an initial increase in defecation, followed by a gradual decline back to the baseline level after 8 rotation sessions. Unlike defecation, the Kaolin consumption of rats showed a bitonic function during the daily rotation sessions (2h daily for 33 consecutive days) and finally recovered to the baseline after about 31 sessions. Immunohistochemistry study revealed increased Fos immunolabeled (Fos-LI) neurons in the medial vestibular nucleus and spinal vestibular nucleus during the initial 7 rotation sessions, and it decreased to the baseline level after 10 rotation sessions. There was a strong linear relationship between the amount of Fos-LI neurons and rat defecation level throughout the whole rotation sessions. These results suggest that the change of neuronal plasticity in the caudal vestibular nucleus might contribute to attenuation of gastrointestinal symptoms during motion sickness habituation process.

Excitatory pathways from the vestibular nuclei to the NTS and the PBN and indirect vestibulo-cardiovascular pathway from the vestibular nuclei to the RVLM relayed by the NTS.

Previous studies have confirmed the existence of vestibulo-sympathetic pathways in the central nervous system. However, the exact pathways and neurotransmitters underlying this reflex are unclear. The present study was undertaken to investigate whether the vestibulo-cardiovascular responses are a result of activated glutamate receptors in the caudal vestibular nucleus. We also attempt to verify the indirect excitatory pathways from the vestibular nucleus (VN) to the rostral ventrolateral medulla (RVLM) using a tracing method combined with a vesicular glutamate transporter (VGluTs) immunofluorescence. In anesthetized rats, unilateral injection of l-glutamate (5 nmol) into the medial vestibular nucleus (MVe) and spinal vestibular nucleus (SpVe) slightly increased the mean arterial pressure (MVe: 93.29+/-11.58 to 96.30+/-11.66, SpVe: 91.72+/-15.20 to 95.48+/-17.16). Local pretreatment with the N-methyl-D-aspartate (NMDA)-receptor antagonist MK-801 (2 nmol) significantly attenuated the pressor effect of L-glutamate injected into the MVe compared to the contralateral self-control. After injection of biotinylated dextran amine (BDA) into the MVe and SpVe, and fluorogold (FG) into the RVLM, some BDA-labeled fibres and terminals in the nucleus of solitary tract (NTS) and the parabrachial nucleus (PBN) were immunoreactive for VGluT1 and VGluT2. Several BDA-labeled fibres were closely apposed to FG-labeled neurons in the NTS. These results suggested that activation of caudal vestibular nucleus neurons could induce pressor response and NMDA receptors might contribute to this response in the MVe. The glutamatergic VN-NTS and VN-PBN pathways might exist, and the projections from the VN to the RVLM relayed by the NTS comprise an indirect vestibulo-cardiovascular pathway in the brain stem.