Parasympathetic Nervous Function Research Articles

PSXIII-13 Evaluation of physiological functions and performance in laying hens in different housing systems

Abstract Egg production faces many challenges of economics, disease control and animal welfare concerns. Therefore, investigation of physiological characteristics in laying hens should be required for further discussion on such issues from a scientific point of view. In this study, we evaluated physiological functions and production parameters of hens raised in three different housing systems, conventional battery cage (CC), enriched cage (EC) and aviary system (AV). Lohmann Selected Leghorn Lite laying hens (n = 251) were used. At first, all the pullets were housed in CC. Then, a telemetric transmitter was implanted to randomly selected 18 hens on d 171 after birth to record electrocardiograms (ECGs), heart rate (HR), body temperature (BT) and locomotor activity (LA). Heart rate variability (HRV), which was analyzed using ECG, has been established as a suitable method for investigating autonomic nervous functions, and to assess stress and well-being of housing systems. On d 200 after birth, some of the hens were randomly selected and transferred to EC or AV (CC; n = 88, EC; n = 72, AV; n = 91), including hens implanted a transmitter (6 hens in each group). All parameters at 10 d before and 1 wk after the group division were compared. Egg laying rate (ELR), feed conversion ratio (FCR) and shell deformation were evaluated for egg production parameters. Hens were basically housed under the same management condition, and a constant light-dark cycle (light-on from 0300 to 1930 h). Feeding was conducted during light-phase, and water was supplied ad libitum. Statistical significance was defined as P < 0.05. Comparing the physiological parameter, HR during dark-phase and LA during light-phase after transferred to EC or AV were greater than those in CC. However, there was no significant difference in HR during light-phase or LA during dark-phase between CC and the other two groups. The high frequency (HF) power of HRV, which reflects parasympathetic nervous function, was high during the dark-phase (7.59 ± 1.56) and low during the light-phase (6.04 ± 0.78) in CC. This diurnal variation disappeared in EC or AV because the HF power during the dark-phase decreased. As for production, ELR, FCR and shell deformation were decreased after moved to AV, which were not found in other two groups after the group division. This study was conducted to clarify the effects of housing systems on the physiological functions and productivity of laying hens, and these results suggest that CC might provide hens with parasympathetic dominance with greater quality of rest in dark-phase, and AV causes the reduction of egg production. However, we cannot completely rule out the possibility that these results are influenced by movement to a different housing system. Therefore, further analysis should be performed to assess the relations between physiological functions, management and egg production.

Exposure to prenatal stressors and infant autonomic nervous system regulation of stress.

The purpose of this study was to determine the relationship between fetal exposure to maternal prenatal stressors and infant parasympathetic (PNS) and sympathetic (SNS) nervous function at 3 timepoints across the first year of life. Autonomic nervous system impairments may mediate associations between gestational exposure to stressors and later infant health problems. Heart rate variability (HRV) provides a sensitive index of PNS and SNS function. However, no studies have assessed longitudinal associations between prenatal stressors and infant HRV measures of both PNS and SNS over the first year of life. During the third trimester of pregnancy, 233 women completed measures of life stressors and depression. At 1, 6 and 12 months of age, a stressor protocol was administered while infant electrocardiographic (ECG) data were collected from a baseline through a post-stressor period. HRV measures of PNS and SNS activity (HF, LF, LF/HF ratio) were generated from ECG data. We used multilevel regression to examine the aims, adjusting for maternal depression and neonatal morbidity. There were no associations between prenatal stressors and any baseline or reactivity HRV metric over the infant's first year of life. However, exposure to more stressors was associated with lower post-stressor LF HRV at both 6 (β = -.44, p = .001) and 12 (β = -.37, p = .005) months of age. Findings suggest potential alterations in development of the vagally mediated baroreflex function as a result of exposure to prenatal stressors, with implications for the infants' ability to generate a resilient recovery in response to stressors.

Exercise Attenuates Myocardial Ischemia-Reperfusion Injury by Regulating Endoplasmic Reticulum Stress and Mitophagy Through M2 Acetylcholine Receptor.

Aims: Adaptive changes in the heart by exercise have been shown to reduce the risk of cardiovascular disease, and M2 Acetylcholine receptor (M2AChR), a receptor abundantly present on cardiac parasympathetic nerves, is closely associated with the development of cardiovascular disease. The present study intends to investigate whether exercise can regulate endoplasmic reticulum stress (ERS) and mitophagy through M2AChR to resist myocardial ischemia-reperfusion (I/R) injury and to elucidate its mechanism of action. Results: Exercise enhanced parasympathetic nerve function and increased myocardial M2AChR protein expression in I/R rats. In addition, it promoted the protein expression of MFN2 and inhibited the expression of Drp1, Chop, PINK1/Parkin, and PERK/eIF2α/ATF4 signaling pathways, effectively reducing mitophagy, ERS, and apoptosis. At the cellular level, 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) reduced hypoxia/reoxygenation (H/R)-induced ERS through the downregulated expression of PERK/eIF2α/ATF4 pathway proteins in H9C2 cardiomyocytes. When intervened with M2AChR inhibitors, the levels of ERS and phosphorylation levels of the PERK/eIF2α/ATF4 pathway were increased in H/R cells. Innovation and Conclusion: Exercise intervention activated the parasympathetic state in rats. It inhibited myocardial mitophagy and ERS levels, and reduced myocardial apoptosis through M2AChR, thereby resisting I/R-induced myocardial injury and improving cardiac function. Antioxid. Redox Signal. 40, 209-221.

Relationship Between the Onset of Ménière's Disease and Sympathetic Hyperactivity.

ObjectiveThe pathogenesis of Ménière's disease is still largely unknown; however, it is known to be strongly associated with stress. Excessive stress can cause hyperactivity of the sympathetic autonomic nervous system. With the aim of understanding changes in sympathetic hyperactivity before and after Ménière's disease, we compared autonomic nervous function in patients in a stable phase of Ménière's disease and that in healthy adults. We also gathered data over about 10 years on autonomic nervous function immediately before a Ménière's attack.Study DesignProspective study.PatientsAutonomic nervous function was analyzed in 129 patients in a stable phase of Ménière's disease 31 healthy adult volunteers. In nine patients, autonomic nervous function was also measured immediately before and after treatment of a vertigo attack.Main Outcome MeasurePower spectrum analysis of heart rate variability (HRV) of EEG/ECG and an infrared electronic pupillometer were used. Sympathetic and parasympathetic nervous function was measured.ResultsThere were no statistically significant differences in autonomic nervous function determined by HRV and electronic pupillometry between patients in a stable phase of Ménière's disease and healthy adults. Sympathetic function as measured by electronic pupillometry parameters VD and T5 showed no difference between the affected and unaffected sides in the baseline data measured in the stable phase (VD: affected side is 31.02 ± 6.16 mm/sec, unaffected side is 29.25 ± 5.73 mm/sec; T5: affected side is 3.37 ± 0.43 msec, unaffected side is 3.25 ± 0.39 msec). In contrast, all nine patients whose HRV data had been obtained just before an attack showed marked suppression of the parasympathetic nervous system and activation of the sympathetic nervous system. Electronic pupillometry also revealed an overactivation of the sympathetic nervous system on the affected side, just before the attacks. Analysis of sequential changes after the onset of an attack revealed that overactivation on the affected side was reduced after treatment, and no difference between affected and unaffected sides was observed 3 days after treatment.ConclusionDetailed analysis of autonomic nervous function showed that immediately before an attack of Ménière's disease, the sympathetic nervous system on the affected side was strongly overactivated.

A Case of Leporine Dysautonomia from Croatia

Abstract Leporine dysautonomia (or dysautonomia of hares) is an idiopathic disorder associated with degeneration of neurons of the peripheral nervous system with loss of sympathetic and parasympathetic nerve function. The disease has so far been described in rabbits and hares from Great Britain, and a similar disorder has also been described in horses (grass sickness), dogs and cats (Key-Gaskell syndrome) throughout the world. We describe a case of leporine dysautonomia in a rabbit from Croatia, characterized by gross findings of cachexia, dehydration, dilated intestines and urinary bladder. Histologic findings included severe vacuolation of neurons of the submucous and myenteric plexus in the intestinal tract. This disease presents a rare disorder of rabbits, and based on current report, it should be considered as a possible differential diagnosis is rabbits with neurologic clinical signs and mild gross findings including cachexia and distension of intestine and urinary bladder.

Angiotensin II and the Cardiac Parasympathetic Nervous System in Hypertension.

The renin–angiotensin–aldosterone system (RAAS) impacts cardiovascular homeostasis via direct actions on peripheral blood vessels and via modulation of the autonomic nervous system. To date, research has primarily focused on the actions of the RAAS on the sympathetic nervous system. Here, we review the critical role of the RAAS on parasympathetic nerve function during normal physiology and its role in cardiovascular disease, focusing on hypertension. Angiotensin (Ang) II receptors are present throughout the parasympathetic nerves and can modulate vagal activity via actions at the level of the nerve endings as well as via the circumventricular organs and as a neuromodulator acting within brain regions. There is tonic inhibition of cardiac vagal tone by endogenous Ang II. We review the actions of Ang II via peripheral nerve endings as well as via central actions on brain regions. We review the evidence that Ang II modulates arterial baroreflex function and examine the pathways via which Ang II can modulate baroreflex control of cardiac vagal drive. Although there is evidence that Ang II can modulate parasympathetic activity and has the potential to contribute to impaired baseline levels and impaired baroreflex control during hypertension, the exact central regions where Ang II acts need further investigation. The beneficial actions of angiotensin receptor blockers in hypertension may be mediated in part via actions on the parasympathetic nervous system. We highlight important unknown questions about the interaction between the RAAS and the parasympathetic nervous system and conclude that this remains an important area where future research is needed.

Correlation between Palpitations below the Heart in Traditional Chinese Medicine and Autonomic Nerve Function Based on Heart Rate Variability: A Case-Control Study.

Objective To explore the autonomic nerve rhythm and the correlation between palpitations below the heart (PBTH) and autonomic nerve function in patients with PBTH based on heart rate variability (HRV). Methods The outpatients or ward patients of Wenzhou Hospital of Traditional Chinese Medicine were collected and divided into two groups: the PBTH group and the normal group. The HRV of each group was detected. Single-factor statistical methods, Spearman correlation analysis, and logistic regression were used to describe and analyze the rhythm and characteristics of autonomic nerves in patients with PBTH and the correlation between PBTH and autonomic nerve function. Results (1) In the comparison of HRV in different time periods in the same group, the SDNN, RMSSD, pNN50, TP, and HF in the PBTH group at night were significantly higher than those in the daytime (P < 0.01), while the LF/HF ratio was significantly lower than that in the daytime (P < 0.01). (2) In the comparison of HRV between the two groups in the same time period, the RMSSD and pNN50 of the PBTH group during the daytime period were significantly higher than those of the normal control group (P < 0.05), and the LF/HF was significantly lower than that of the normal group (P < 0.05). (3) In the Spearman correlation analysis, PBTH was significantly correlated with RMSSD, pNN50, and LF/HF ratio in the daytime period, with correlation coefficients of 0.424, 0.462, and −0.524, respectively (P < 0.05). (4) Logistic regression analysis showed that the decrease of LF/HF ratio during the daytime period was an independent risk factor for PBTH in TCM (OR = 0.474, 95% CI: 0.230–0.977, P < 0.05). Conclusions The changes in parasympathetic nerve function in patients with PBTH have a circadian rhythm, which is characterized by increased activity during the nighttime. At the same time, the autonomic nerve activity of people with PBTH during the daytime is unbalanced, and the decrease of LF/HF ratio during the day is an independent high risk factor for PBTH.

Parasympathetic Nerve Function Status in Major Depressive Disorder Patients and Its Correlation with Duration of Disease

Introduction:Cardiovascular (CV) morbidity is a major problem in patients suffering from depression. Greater CV mortality is found in cardiac patients with depression than without depression. Depressive disorder can cause altered autonomic nerve function. This study design to assess autonomic nerve function activity by heart rate variability analysis in patients with major depressive disorder and its correlation with duration of disease.&#x0D; Materials and Methods: This case study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Shahbag, Dhaka in 2011. 60 patients of both sexes with major depressive disorder (MDD) aged from 20-50 years were included in the study group (Group B). The patients were selected from out and inpatient Department of Psychiatry in Bangabandhu Sheik Mujib Medical University (BSMMU). Group B were divided into B-1 consisting of 30 drug naive MDD patients &amp; B-2 consisting of 30 medicated MDD patients. For comparison age and sex matched 30 apparently healthy subjects (Group A) were also studied. The HRV parameters were recorded by 4 active channels, Polyrite-D machine. For statistical analysis ANOVA, independent sample t-test, chi-square test and Pearson’s correlation coefficient test were performed by using SPSS for windows version-16 as applicable.&#x0D; Results: Mean resting pulse rate, mean heart rate, systolic blood pressure were significantly higher in drug naive and medicated MDD patients in comparison with that of healthy control. Mean R-R interval, Max/Min R-R interval, SDNN, RMSSD, PNN50%, NN50% were significantly lower in this groups of patients. Correlation analysis showed negative correlations of SDNN, RMSSD, PNN50%, NN50% with disease duration which was statistically significant only for SDNN.&#x0D; Conclusion: Sympathovagal imbalance may occur in both drug naive and medicated MDD patients which is associated with higher sympathetic and lower vagal modulation of the heart rate. In addition, parasympathetic nerve function parameters show negative relationship with the duration of disease.&#x0D; Medicine Today 2020 Vol.32(2): 76-80

Evaluation of Fatigue in Cancer Patients in An Area Affected by the Great East Japan Earthquake

Objective:The objective of this study is to evaluate fatigue in cancer outpatients receiving chemotherapy using an objective system and to clarify the type of nursing support needed after a disaster.Methods:Based on the diagnostic criteria for chronic fatigue syndrome, the degree of subjective fatigue, autonomic function, and amount of physical activity were measured in cancer outpatients undergoing chemotherapy from an area affected by the Great East Japan Earthquake.Results:The study participants were ten adults (8 men [80.0%] and 2 women [20.0%]). Significant differences were seen in subjective physical fatigue (P = 0.347), mental fatigue (P = 0.128), comprehensive fatigue (P = 0.621), and comprehensive evaluations (P = 0.293); however, no significant differences were seen in the results for changes over time for any survey item. The balance between sympathetic and parasympathetic nerve function changed statistically significant with time (log low frequency [LF] [P = 0.039] and log LF/high frequency [HF] [P = 0.021]). In all participants, autonomic nervous function was enhanced in the sympathetic nervous system, and the sympathetic nervous system was dominant. Significant differences were observed between the three measurements for mean diurnal activity (P = 0.027), total sleep time (P = 0.011), sleep efficiency (P = 0.019), awakening (P = 0.032), and naps (P = 0.037).Conclusions:In the event of a disaster, in addition to self-care support for side effects caused by anticancer drugs, patients' physical and mental conditions are assessed in terms of fatigue using objective indicators, and then, appropriate nursing support is provided. The nurse grasps objective facts behind the patient's subjective data and systematically recommends adjustments to the patient's daily life. In addition, by providing appropriate information to patients, patient education specific to each patient is provided.

Study of the Distribution of Epicardial Vagal Ganglion and the Relationship Between Delayed Enhancement Magnetic Resonance Imaging and Radiofrequency Ablation in Patients with Atrial Fibrillation

This article presents a retrospective study of patients undergoing radiofrequency ablation of atrial fibrillation (AF); analyzes the characteristics of heart rate variability (HRV) in patients; and explores the role of delayed enhancement magnetic resonance imaging and autonomic nervous system function, changes in autonomic nervous system function, and recurrence of AF after radiofrequency ablation to understand the effect of denervation of the autonomic nervous system on the efficacy of radiofrequency ablation of AF. The study found that there were no significant differences in clinical baseline characteristics, mean heart rate, and HRV indicators between patients without relapse and patients with relapse (P > 0.05). The overall HRV index was significantly reduced after surgery as well as before surgery. In the relapse-free group, the high-frequency power that responded to vagal tone was more significant, the low-frequency/high-frequency power ratio increased, and other HRV indicators were significantly reduced; in the relapse group, mean heart rate increased, sympathetic response to the low-frequency power of nerve tension was significantly reduced, and the low-frequency/high-frequency power ratio was decreased. The difference was statistically significant (P < 0.05). Therefore, sympathetic and parasympathetic nerve function were significantly reduced after radiofrequency ablation of the pulmonary veins in patients with AF. Reducing vagus nerve tension may inhibit early recurrence of paroxysmal AF in patients after left atrial ring pulmonary vein ablation.

Instability of nocturnal parasympathetic nerve function in patients with chronic lung disease with or without nocturnal desaturation

Objective/backgroundThis study was performed to evaluate the association of nocturnal autonomic nerve (AN) dysfunction, especially parasympathetic nerve (PN) function instability, and nocturnal oxygen desaturation (NOD) in patients with chronic lung diseases (CLD).Patients and methodsTwenty-nine stable CLD patients with irreversible pulmonary dysfunction and mild-to-moderate daytime hypoxemia, 13 CLD patients receiving long-term oxygen therapy (LTOT) with maintained SpO2 >90%, and 17 senior healthy volunteers underwent two-night examinations of nocturnal AN function by pulse rate variability (PRV) instead of heart rate variation using a photoelectrical plethysmograph simultaneously monitoring SpO2 and the presence of sleep disordered breathing at home. AN function was examined by instantaneous time–frequency analysis of PRV using a complex demodulation method.ResultsThere were no significant differences in mean low frequency/high frequency (HF) ratio (index of sympathetic nerve activity) or mean HF amplitude (index of PN activity) among controls and CLD patients with and without NOD (defined as SpO2 <90% for at least 3% of total recording time at night). However, the relative times over which the same main HF peak was sustained for at least 20 seconds (%HF20sec) and 5 minutes in total recording time, indexes of PN function stability, were significantly reduced in CLD patients compared with controls, and further decreased in CLD patients with NOD compared with non-NOD. %HF20sec was significantly higher in the LTOT group than the NOD group. Furthermore, PaO2 at rest and nocturnal hypoxia were significantly correlated with PN function instability in CLD patients.ConclusionPN function is unstable at night associated with nocturnal hypoxemia in CLD patients, which may reflect poor quality of sleep.

Dementia May Reduce the Effectiveness of Low-Intensity Pulsed Ultrasound (LIPUS) Following Intramedullary Fixation for Trochanteric Fracture of the Femur

Objectives: Femoral trochanteric fracture often occurs in elderly females with bone fragility, and may accompany the complication of dementia, such as Alzheimer disease. In addition, comminuted fracture and unstable fracture are also confirmed in many cases, but low intensity pulsed ultrasound (LIPUS) is effective in promoting callus formation after osteosynthesis. However, there is a concern that LIPUS may not be effective when dementia develops as a concomitant complication in patients with femoral trochanteric fracture. In this study, we examined the effects of LIPUS to promote callus formation in subjects with and without decreased cognitive function. Subjects and Methods: The inclusion criteria included elderly females who underwent reduction with the use of intramedullary nails of the same type, began to receive load training with no limitation on the day following the surgery, and were followed from surgery to convalescent rehabilitation at our hospital. The exclusion criteria included those who received drugs to increase bone quantity, such as osteoporosis drugs (except for alfacalcidol) and AChEIs, routine steroid administration, or artificial dialysis. The subjects were divided into the decreased cognitive function group with HDS-R of 20 points or less and the non-decreased cognitive function group with 21 points or more. These groups were further divided into the LIPUS treated group and the non-treated group, respectively to compare the appearance of callus confirmed by plain X-ray examination. Results: In the non-decreased cognitive function group, callus formation was significantly promoted by LIPUS, but LIPUS showed no effect in the decreased cognitive function group. Discussions: Patients with dementia, such as Alzheimer disease, exhibit decreased parasympathetic nerve function and decreased bone mass caused by retroplasia of the hypothalamus, as well as protracted synostosis in hip fracture due to dementia. For femoral trochanteric fracture with the complication of decreased cognitive function, concomitant use of LIPUS and AChEIs, which inhibit the aggravation of dementia, may be effective.

Anti-stress effects of simplified aroma hand massage.

In order to be able to use the aroma hand massage as a skill that can be done by a nurse who does not have a special aromatherapy technique, we examine antistress effects of simplified aroma hand massage for healthy subjects. We evaluated the anti-stress action of aroma hand massage and the different components of the procedure in 20 healthy women in their twenties. We used autonomic nervous function measured via electrocardiogram as an index of stress. After conducting a baseline electrocardiogram, we induced stress in the participants by asking them to spend 30 minutes completing Kraepelin’s arithmetic test. We then administered various treatments and examined the anti-stress effects. Kraepelin’s test significantly increased sympathetic nervous function and significantly reduced parasympathetic nervous function. Compared with massage without essential oil or aroma inhalation, aroma hand massage significantly increased parasympathetic nervous function and significantly decreased sympathetic nervous function. The effect of the aroma hand massage persisted when the procedure was simplified. The anti-stress action of the aroma hand massage indicates that it might have beneficial application as a nursing technique. There are several limitations in this study; ambiguities of low component/high component ratio of heart rate variability and bias by small subjects groups of the same women.

The relaxation effect of prolonged expiratory breathing.

This study was performed to confirm that autonomic nervous activity is affected by breathing speed. I hypothesized that prolonged expiratory breathing would promote parasympathetic dominance, whereas rapid breathing would promote sympathetic dominance. Ten healthy men, ages 21-28 years old, were instructed to perform prolonged expiratory breathing (6 seconds expiration, 4 seconds inspiration) after spontaneous breathing and rapid breathing (1 second expiration, 1 second inspiration) after spontaneous breathing; changes in high frequency (HF) and low frequency (LF)/HF of heart rate variability (HRV) were measured during each type of breathing. During prolonged expiratory breathing, parasympathetic nervous function was significantly activated. Conversely, during rapid breathing, parasympathetic nervous function was significantly suppressed. The HRV method assessing sympathetic and parasympathetic modulation in this study is an indirect, non-invasive method with clear limitations. The use of additional techniques should be considered to clarify the relationships between the breathing speed and the mind.

The relaxation effect of prolonged expiratory breathing

This study was performed to confirm that autonomic nervous activity is affected by breathing speed. I hypothesized that prolonged expiratory breathing would promote parasympathetic dominance, whereas rapid breathing would promote sympathetic dominance. Ten healthy men, ages 21-28 years old, were instructed to perform prolonged expiratory breathing (6 seconds expiration, 4 seconds inspiration) after spontaneous breathing and rapid breathing (1 second expiration, 1 second inspiration) after spontaneous breathing; changes in high frequency (HF) and low frequency (LF)/HF of heart rate variability (HRV) were measured during each type of breathing. During prolonged expiratory breathing, parasympathetic nervous function was significantly activated. Conversely, during rapid breathing, parasympathetic nervous function was significantly suppressed. The HRV method assessing sympathetic and parasympathetic modulation in this study is an indirect, noninvasive method with clear limitations. The use of additional techniques should be considered to clarify the relationships between the breathing speed and the mind.

Anti-stress effects of simplified aroma hand massage

In order to be able to use the aroma hand massage as a skill that can be done by a nurse who does not have a special aromatherapy technique, we examine anti-stress effects of simplified aroma hand massage for healthy subjects. We evaluated the anti-stress action of aroma hand massage and the different components of the procedure in 20 healthy women in their twenties. We used autonomic nervous function measured via electrocardiogram as an index of stress. After conducting a baseline electrocardiogram, we induced stress in the participants by asking them to spend 30 minutes completing Kraepelin's arithmetic test. We then administered various treatments and examined the anti-stress effects. Kraepelin's test significantly increased sympathetic nervous function and significantly reduced parasympathetic nervous function. Compared with massage without essential oil or aroma inhalation, aroma hand massage significantly increased parasympathetic nervous function and significantly decreased sympathetic nervous function. The effect of the aroma hand massage persisted when the procedure was simplified. The anti-stress action of the aroma hand massage indicates that it might have beneficial application as a nursing technique. There are several limitations in this study; ambiguities of low component/high component ratio of heart rate variability and bias by small subjects groups of the same women.

Eosinophil and airway nerve interactions in asthma.

Airway eosinophils are increased in asthma and are especially abundant around airway nerves. Nerves control bronchoconstiction and in asthma, airway hyperreactivity (where airways contract excessively to inhaled stimuli) develops when eosinophils alter both parasympathetic and sensory nerve function. Eosinophils release major basic protein, which is an antagonist of inhibitory M2 muscarinic receptors on parasympathetic nerves. Loss of M2 receptor inhibition potentiates parasympathetic nerve-mediated bronchoconstriction. Eosinophils also increase sensory nerve responsiveness by lowering neurons' activation threshold, stimulating nerve growth, and altering neuropeptide expression. Since sensory nerves activate parasympathetic nerves via a central neuronal reflex, eosinophils' effects on both sensory and parasympathetic nerves potentiate bronchoconstriction. This review explores recent insights into mechanisms and effects of eosinophil and airway nerve interactions in asthma.

Instability of parasympathetic nerve function evaluated by instantaneous time–frequency analysis in patients with obstructive sleep apnea

The purpose was to determine whether the instability of parasympathetic nerve (PN) function is associated with fragmentation of sleep and the instability can be improved by CPAP treatment in obstructive sleep apnea (OSA). Fifty-three OSA and 50 non-OSA subjects were examined by full-PSG and pulse rate variability (PRV) was recorded simultaneously using a photoplethysmograph and evaluated by instantaneous time–frequency analysis using the complex demodulation method. PN and sympathetic nerve (SN) activity were assessed by the mean high-frequency (HF) amplitude and ratio of low-frequency (LF) and HF amplitude (LF/HF ratio), respectively. Furthermore, the shift in central frequency (CF) of the main HF peak over time was monitored continuously. The relative times over which the same main HF peak was sustained for at least 20 s and 5 min in total recording time (%HF20s and %HF5min) were considered as markers of PN stability. Twenty-two of 53 patients with OSA also examined under the treatment with continuous positive airway pressure (CPAP). A significant increase in mean LF/HF ratio and decrease in HF amplitude were observed in severe OSA. Furthermore, both %HF20s and %HF5min were significantly decreased not only in mild-to-moderate OSA but also in severe OSA, and %HF20s was the strongest independent determinant for arousal index. Treatment with CPAP significantly decreased the LH/HF ratio and increased both %HF20s and %HF5min. These findings suggest that the stability of PN function is impaired by arousal due to repeated apnea and hypopnea in OSA, and that CPAP therapy improves SN activity and PN dysfunction.

018 TNF-alpha Inhibition Improves Parasympathetic Nerve Function and is Associated with Altered Macrophage Infiltration of the Major Pelvic Ganglion following Nerve Injury

018 TNF-alpha Inhibition Improves Parasympathetic Nerve Function and is Associated with Altered Macrophage Infiltration of the Major Pelvic Ganglion following Nerve Injury

Ozone-induced eosinophil recruitment to airways is altered by antigen sensitization and tumor necrosis factor-α blockade.

Ozone is an atmospheric pollutant that causes lung inflammation and airway hyperresponsiveness. Ozone's effects occur in two distinct phases that are mediated by different populations of eosinophils. In the acute phase 1 day after exposure, mature airway‐resident eosinophils alter parasympathetic nerve function that results in airway hyperresponsiveness. At this time point, the severity of hyperresponsiveness correlates with the number of eosinophils in close proximity to airway nerves, but not with eosinophils in bronchoalveolar lavage. Three days later, newly divided eosinophils are recruited to airways by a tumor necrosis factor‐α‐dependent mechanism. These new eosinophils paradoxically attenuate ozone‐induced airway hyperresponsiveness. Ozone's effects on airway tissue eosinophils and nerve‐associated eosinophils 3 days after exposure are unknown. Thus, we tested ozone's effects on eosinophils in airway subepithelium and around airway nerves 1 and 3 days after ozone in nonsensitized and ovalbumin‐sensitized guinea pigs with or without the tumor necrosis factor‐α antagonist, etanercept, and compared changes in eosinophils with ozone‐induced airway hyperresponsiveness. More eosinophils were present in small, noncartilaginous airways and along small airway nerves compared to large cartilaginous airways in all treatment groups. The number of airway and nerve‐associated eosinophils were unaffected 1 day after ozone exposure, whereas significantly fewer airway eosinophils were present 3 days later. Airway and nerve‐associated eosinophils were also decreased in small airways 3 days after ozone in sensitized animals. These changes were blocked by etanercept. Airway eosinophils, but not nerve‐associated or bronchoalveolar lavage eosinophils correlated with airway hyperresponsiveness 3 days after ozone. Our findings indicate ozone causes persistent alterations in airway eosinophils and reinforce the importance of characterizing eosinophils’ effects within distinct airway compartments.