Airway and tissue mechanics in ventilated patients with pneumonia

We applied the low-frequency forced oscillation technique (LFOT) to measure respiratory impedance (Zrs) at various positive end-expiratory pressures (PEEPs) in 14 sedated and intubated patients with pneumonia classified into a mild (Group 1) and a severe group (Group 2) based on lung injury scores. The Zrs spectra were fit with the constant-phase (CP) model including Newtonian resistance (R_N) and tissue damping (G) and elastance (H), a distributed airway resistance (DR) and a distributed tissue elastance (DH) model. Using the CP model, all parameters revealed a negative PEEP dependence (p < 0.001) in Group 2 and H was higher in Group 2 (p = 0.014). The variability of H from the DH model was nearly significantly larger in Group 1 (p = 0.061). Following bronchodilator inhalation, G significantly decreased (p = 0.009). Thus, the CP model provides a robust partitioning of Zrs into tissue properties and R_N, a surrogate for airway resistance, while the distributed models suggest that lung heterogeneity decreases with increasing PEEP.     

Respiratory input impedance measurement: Forced oscillation methods

The paper reviews how forced oscillation techniques (FOT) for measuring respiratory input impedance Z_{rs, in} have recently been used in clinical applications. Z_{rs, in} is clinically relevant, as it provides data on both the resistive, R_rs, and nonresistive, X_rs, components of the respiratory system. Additionally, when excitatory test signals extending into low- (<4 Hz) or high-frequency (>100 Hz) ranges are used, reliable partitioning of lung tissue from airway components is feasible. Adult and paediatric studies examining the use of Z_{rs, in} for routine lung-function assessment, sleep and mechanical ventilation are reviewed. For clinicians, Z_{rs, in} is repeatable and sensitive to airway resistance. It is helpful for assessing unco-operative and severely obstructed patients, for monotoring mechanics during artificial ventilation and for tracking airway closure during sleep studies. For paediatricians, longitudinal studies of the growth and development of the respiratory system can also be made using Z_{rs, in}. Forced oscillation techniques, however, require further standardisation, and Z_{rs, in} is limited by upper-airway shunt artifacts. In conclusion, measurement of Z_{rs, in} using FOT is an important and sophisticated non-invasive lung-function test, showing good potential for future clinical applications.     

Comprehensive integrated spirometry using raised volume passive and forced expirations and multiple-breath nitrogen washout in infants

With the rapid somatic growth and development in infants, simultaneous accurate measurements of lung volume and airway function are essential. Raised volume rapid thoracoabdominal compression (RTC) is widely used to generate forced expiration from an airway opening pressure of 30 cmH₂O (V₃₀). The (dynamic) functional residual capacity (FRC_dyn) remains the lung volume most routinely measured. The aim of this study was to develop comprehensive integrated spirometry that included all subdivisions of lung volume at V₃₀ or total lung capacity (TLC₃₀). Measurements were performed on 17 healthy infants aged 8.6–119.7 weeks. A commercial system for multiple-breath nitrogen washout (MBNW) to measure lung volumes and a custom made system to perform RTC were used in unison. A refined automated raised volume RTC and the following two novel single maneuvers with dual volume measurements were performed from V₃₀ during a brief post-hyperventilation apneic pause: (1) the passive expiratory flow was integrated to produce the inspiratory capacity (IC) and the static (passive) FRC (FRC_st) was estimated by initiating MBNW after end-passive expiration; (2) RTC was initiated late during passive expiration, flow was integrated to produce the slow vital capacity (_jSVC) and the residual volume (RV) was measured by initiating MBNW after end-expiration while the jacket (j) was inflated. Intrasubject FRC_dyn and FRC_st measurements overlapped (p = 0.6420) but neither did with the RV (p < 0.0001). Means (95% confidence interval) of FRC_dyn, IC, FRC_st, _jSVC, RV, forced vital capacity and tidal volume were 21.2 (19.7–22.7), 36.7 (33.0–40.4), 21.2 (19.6–22.8), 40.7 (37.2–44.2), 18.1 (16.6–19.7), 40.7 (37.1–44.2) and 10.2 (9.6–10.7) ml/kg, respectively. Static lung volumes and capacities at V₃₀ and variables from the best forced expiratory flow-volume curve were dependent on age, body length and weight. In conclusion, we developed a comprehensive physiologically integrated approach for in-depth investigation of lung function at V₃₀ in infants.     

Increased load on the respiratory muscles in obstructive sleep apnea

We wished to quantify, in patients with obstructive sleep apnoea (OSA), the activity of the respiratory muscles in relation to upper airway occlusion and patency in sleep. We hypothesized that particular levels of neuromuscular activation are directly associated with upper airway patency. 21 patients with previously diagnosed OSA and 21 healthy control subjects underwent respiratory muscle testing and polysomnography. Neural respiratory drive, as measured by the electromyogram of the diaphragm (EMG_di) was elevated in the obese OSA patients, awake and supine (13.1(5.6)%max), compared to normal subjects (mean (SD) 8.1(2.3)%max, p < 0.01). During unobstructed breathing in sleep (stage N2) normal subjects had an EMG_di of 7.7(3.9) compared to 22.8(19.2)%max in the OSA group (p < 0.001). Prior to airway occlusion, EMG_{submandibular} and EMG_di dropped markedly, and then, following occlusion, increased progressively to their highest levels at airflow onset. Patients with OSA require specific and increased levels of neural respiratory drive to sustain ventilation in sleep.     

Measuring Upper and Lower Airway Resistance During Sleep with the Forced Oscillation Technique

The forced oscillation technique (FOT) is a non-invasive technique to monitor airway obstruction in those with asthma. The aim of this study was to design and validate a system to use FOT during sleep, both with and without bi-level positive airway pressure (BPAP), and to separate upper airway resistance from lower. 8 Hz pressure oscillations were supplied, over which the subject breathed, pressure and flow measurements were then used to calculate impedance. A phase-shift induced by the pressure transducer tubing was characterized, and FOT resistance was compared to steady flow resistance both with and without BPAP. A Millar catheter was used to measure pressure at the epiglottis, allowing the separation of upper from lower airway resistance. A phase shift of −0.010 s was calculated for the pressure transducer tubing, and the average error between FOT and steady flow resistance was −0.2 ± 0.2 cmH₂O/L/s without BPAP and 0.4 ± 0.2 cmH₂O/L/s with BPAP. The system was tested on three subjects, one healthy, one with obstructive sleep apnea, and one with asthma. The FOT was well tolerated and resistance was separated into upper and lower airway components. This setup is suitable for monitoring both upper and lower airway obstruction during sleep in those with and without asthma.     

Predictors of phase III slope of nitrogen single-breath washout in COPD

The nitrogen (N₂) single-breath washout (SBW) test is a measure of ventilation distribution inhomogeneity and also a small airway function that offers complementary information to spirometry; however, the relevance to the forced oscillation technique (FOT) and pulmonary emphysema in COPD is not fully understood. We hypothesized that pulmonary functions, forced oscillatory parameters, and emphysema extent would contribute independently to the results of the SBW test. In this cross-sectional study we assessed the relationship between the phase III slope (delta N₂) derived from N₂ SBW and these parameters. Spirometry, lung volumes, N₂ SBW, and the broadband frequency FOT were performed in 56 patients with COPD. Emphysema extent was measured by high-resolution computed tomography and scored. In multiple regression analyses, the delta N₂ was independently predicted by forced vital capacity, resonant frequency, and emphysema score (R² = 0.57, p < 0.0001). The degree of ventilation inhomogeneity derived from N₂ SBW is independently predicted by spirometry, lung mechanics, and the degree of emphysema.     

Nano-TiO2 particles impair adhesion of airway epithelial cells to fibronectin

Titanium dioxide engineered nanoparticles (nano-TiO₂) are widely used in the manufacturing of a number of products. Due to their size (<100 nm), when inhaled they may be deposited in the distal lung regions and damage Clara cells. We investigated the mechanisms by which short-term (1-h) incubation of human airway Clara-like (H441) cells to nano-TiO₂ (6 nm in diameter) alters the ability of H441 cells to adhere to extracellular matrix. Our results show that 1 h post-incubation, there was a 3-fold increase of extracellular H₂O₂, increased intracellular oxidative stress as demonstrated by 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) oxidation, and a 5-fold increase of phosphor-ERK1/2 as measured by Western blotting. These changes were accompanied by a 25% decrease of H441 adherence to fibronectin (p < 0.05 compared to vehicle incubated H441 cells). Pretreatment with the ERK1/2 inhibitor U0126 for 3 h, partially prevented this effect. In conclusion, short-term exposure of H441 cells to nano-TiO₂ appears to reduce adherence to fibronectin due to oxidative stress and activation of ERK1/2.     

Assessment of upper airway mechanics during sleep

Obstructive sleep apnea, which is the most prevalent sleep breathing disorder, is characterized by recurrent episodes of upper airway collapse and reopening. However, the mechanical properties of the upper airway are not directly measured in routine polysomnography because only qualitative sensors (thermistors for flow and thoraco-abdominal bands for pressure) are used. This review focuses on two techniques that quantify upper airway obstruction during sleep. A Starling model of collapsible conduit allows us to interpret the mechanics of the upper airway by means of two parameters: the critical pressure (P_crit) and the upstream resistance (R_up). A simple technique to measure P_crit and R_up involves the application of different levels of continuous positive airway pressure (CPAP) during sleep. The forced oscillation technique is another non-invasive procedure for quantifying upper airway impedance during the breathing cycle in sleep studies. The latest developments in these two methods allow them to be easily applied on a routine basis in order to more fully characterize upper airway mechanics in patients with sleep breathing disorders.     

Compartmental chest wall volume changes during volitional hyperpnoea with constant tidal volume in healthy individuals

Prolonged high-intensity ventilation is associated with the development of rapid shallow breathing with decreased end-inspiratory volumes of all chest wall compartments. During respiratory muscle endurance training using normocapnic hyperpnoea, tidal volume (V_T) is normally kept constant. The aim of this study was to investigate possible changes in muscle recruitment during constant-V_T hyperpnoea, to assess potential mechanisms related to rapid shallow breathing. Ten healthy subjects performed 1 h of normocapnic hyperpnoea at 70% of maximal voluntary ventilation. Chest wall volume changes were assessed by optoelectronic plethysmography. End-inspiratory (1.08 ± 0.18 versus 0.96 ± 0.27 l, p = 0.017) and end-expiratory volumes (−0.13 ± 0.15 versus −0.31 ± 0.19 l, p = 0.007) of the pulmonary ribcage decreased significantly and lung function and respiratory muscle strength were reduced (all p < 0.05). Since with forced, constant V_T only the inspiratory rib cage muscles were unable to sustain end-inspiratory volume of their compartment, inspiratory rib cage muscles are the most likely candidate responsible for the development of rapid shallow breathing.     

Immune modulation of ovalbumin-induced lung injury in mice using β-glucosylceramide and a potential role of the liver

CD1d-restricted natural killer T (NKT) cells are implicated in the pathogenesis of asthma. β-Glucosylceramide (GC), a naturally occurring lipid, was previously shown to alter NKT cell distribution in the liver. We hypothesized that GC can affect lung and liver NKT cell distribution and ameliorate asthma. Mice were sensitized by intra-peritoneal injection of ovalbumin (OVA) for 2 weeks followed by repeated intranasal OVA challenges to induce lung injury mimicking asthma. OVA induced asthma groups were either treated by intranasal instillation of normal saline, intranasal instillation of GC or inhaled budesonide. To investigate the role of the liver, hepatic fibrosis was induced using carbon tetrachloride prior to asthma induction. Allergen induced bronchoconstriction was measured prior to sacrifice. Isolated lymphocytes from lungs, livers and spleens were analyzed for OVA induced proliferation and flow cytometry. Liver and lung histology, serum aminotransferase and anti-OVA antibodies level were assessed. Treatment with GC significantly reduced OVA induced airway responsiveness (p < 0.001) similar to inhaled budesonide. GC significantly reduced the peri-bronchial and peri-vascular inflammatory infiltration mainly through an effect on T cells, as suggested by decreased T cell proliferation (p = 0.009). Liver CD4 and NKT cells significantly increased after GC treatment suggesting liver involvement. Inducing hepatic fibrosis blunted the propagation of asthma in spite of sufficient increase of serum anti-OVA titers. GC has an immunomodulatory effect on a murine model of experimental asthma. We also suggest that the liver acts as an immunomodulatory organ and might have a regulatory effect on pulmonary diseases.     

Axial distribution of nitric oxide airway production in asthma patients

In healthy subjects, axial distribution of nitric oxide (NO) airway production is likely heterogeneous: notably a distal peak of production in terminal bronchioles and a quasi-nil NO production in the most of the conducting airways. In asthma, few information exists about the contributions of the proximal and distal airways to NO overproduction. In 18 asthma patients, sites of constriction after methacholine and adenosine 5′-monophosphate (AMP) challenges were assessed by ventilation distribution tests with He and SF₆. The resulting decreases in fractional exhaled NO (FENO) were measured. Changes in He and SF₆ slopes indicated a pre-acinar bronchoconstriction due to AMP and a more proximal action for methacholine. FENO decreased by 38.7% and 20.2% (p < 0.001) after AMP and methacholine challenges, respectively. Significant FENO decreases after AMP and methacholine implies substantial pre-acinar but also, contrary to healthy subjects, more proximal airway production. In conclusion, nitric oxide overproduction in asthma patients appears to involve the most part of the conducting airways.     

Serotonergic receptor upregulation in cerebral cortex and down regulation in brainstem of streptozotocin induced diabetic rats: Antagonism by pyridoxine and insulin

Insulin secretion and glucose homeostasis is implicated through serotonergic function. Pyridoxine is involved in decarboxylation step in synthesis of serotonin. The present study was carried out to find the role of insulin in combination with pyridoxine on the concentrations of 5-HT and 5-HIAA, 5-HT receptor binding, 5-HTT gene expression and immunohistochemistry studies in the cerebral cortex and brainstem of streptozotocin induced diabetic rats. 5-HT content showed a significant decrease with a significant increase in 5-HIAA in cerebral cortex (p < 0.01) and brain stem (p < 0.001) in diabetic rats. 5-HT receptor binding parameters, B_max and K_d, showed a significant decrease (p < 0.001) in diabetic rats in cerebral cortex whereas in brainstem it showed a significant increase (p < 0.001) compared to control. Gene expression studies of 5-HTT in cerebral cortex showed a significant down regulation (p < 0.001) and in brainstem an upregulation (p < 0.001) in diabetic rats compared to control. Insulin and pyridoxine treatment to diabetic rats reversed the 5-HT content, B_max, K_d and gene expression of 5-HTT confirmed by immunohistochemistry studies in cerebral cortex and brainstem to near control. Thus our results suggest that pyridoxine along with insulin has a role in the regulation of insulin synthesis and release through serotonergic function which has clinical significance in the management of diabetes.     

IL21 and IL21R polymorphisms and their interactive effects on serum IL-21 and IgE levels in patients with chronic hepatitis B virus infection

Interleukin (IL)-21 may affect both T-cell and B-cell responses and was suggested to be involved in response to HBV infection. This study explored IL21rs907715 and rs2221903 and IL21R T-83C and rs3093301 polymorphisms and serum IL-21 and IgE levels in 395 patients with chronic HBV infection, 75 HBV infection resolvers and 174 healthy controls. IL21R T-83C was not polymorphic in the study populations. IL21 rs2221903 AG was less frequent in HBV patients than in resolvers (p < 0.001, OR = 0.364, 95% CI = 0.211–0.629) or in controls (p = 0.017, OR = 0.589, 95% CI = 0.381–0.911). IL21R rs3093301 TT was more frequent in HBV patients than in controls [p value after Bonferroni correction (p_c) = 0.022, OR = 1.908, 95% CI = 1.158–3.142] and more frequent in resolvers than in controls (p_c = 0.010, OR = 2.965, 95% CI 1.375–6.392). The carriage of IL21 rs2221903 AG/IL21R rs3093301 CT + IL21 rs2221903 AG/IL21R rs3093301 TT was less frequent in patients than in resolvers (p_c = 0.007, OR = 0.236, 95% CI = 0.096–0.579) and more frequent in resolvers than in controls (p_c = 0.014, OR = 4.354, 95% CI = 1.660–11.420). IL21 rs2221903 was, by interaction with IL21R rs3093301, associated with serum IL-21 and IgE levels in HBV patients. It is suggested that IL21 rs2221903 and IL21R rs3093301 polymorphisms may, independently or interactively, affect the susceptibility to and/or persistence of HBV infection potentially through altering IL-21 and IgE production.     

HMGB1 and RAGE levels in induced sputum correlate with asthma severity and neutrophil percentage

Previous work indicated that high mobility group box-1 (HMGB1) protein may be involved in neutrophilic asthma. Here, we sought to investigate the correlation between HMGB1 and one of its receptors, receptor for advanced glycosylation end products (RAGE), with the severity of bronchial asthma. Compared to the control group (30 healthy individuals), patients in the asthma group (n = 72) exhibited a higher percentage of neutrophils and higher HMGB1 and RAGE levels in induced sputum samples (P < 0.05). Concurrently, FEV₁% was significantly lower in the asthma group (P < 0.05). Further, compared to mild and moderate asthma, in patients with severe asthma ACQ scores, the percentage of neutrophils, and HMGB1 levels were significantly higher, while FEV₁% was significantly lower (P < 0.05). The percentage of neutrophils and HMGB1 and RAGE levels were lower after treatment than before treatment (P < 0.05). Finally, negative correlations were observed between HMGB1 or RAGE levels and FEV₁% (r = −0.777 and r = −0.291, P < 0.05), and positive correlations were detected between HMGB1 or RAGE levels and percentage of neutrophils (r = 0.803 and r = 0.326, P < 0.05). Additionally, positive correlations were observed between HMGB1 and RAGE levels within the asthma group (r = 0.306, P < 0.05). Therefore, HMGB1 protein levels correlate with the severity of asthma, and HMGB1 may contribute to the inflammatory process of asthma.     

Diaphragm motor unit recruitment in rats

We hypothesized that considerable force reserve exists for the diaphragm muscle (DIAm) to generate transdiaphragmatic pressures (Pdi) necessary to sustain ventilation. In rats, we measured Pdi and DIAm EMG activity during different ventilatory (eupnea and hypoxia (10% O₂)–hypercapnia (5% CO₂)) and non-ventilatory (airway occlusion and sneezing induced by intranasal capsaicin) behaviors. Compared to maximum Pdi (Pdi_max generated by bilateral phrenic nerve stimulation), the Pdi generated during eupnea (21 ± 2%) and hypoxia–hypercapnia (28 ± 4%) were significantly less (p < 0.0001) than that generated during airway occlusion (63 ± 4%) and sneezing (94 ± 5%). The Pdi generated during spontaneous sighs was 62 ± 5% of Pdi_max. Relative DIAm EMG activity (root mean square [RMS] amplitude) paralleled the changes in Pdi during different ventilatory and non-ventilatory behaviors (r² = 0.78; p < 0.0001). These results support our hypothesis of a considerable force reserve for the DIAm to accomplish ventilatory behaviors. A model for DIAm motor unit recruitment predicted that ventilatory behaviors would require activation of only fatigue resistant units.     

Circulating IL-35 in pancreatic ductal adenocarcinoma patients

IL-35 is a novel inhibitory cytokine that is mainly produced by regulatory T-cells (Tregs) and is required for Treg-mediated immunosuppression. However, the plasma levels of IL-35 in patients with pancreatic ductal adenocarcinoma (PDAC) have never been investigated. In this study, we found that plasma IL-35 levels more significantly increased in PDAC patients than in normal controls (134.53 ± 92.45 pg/mL vs. 14.26 ± 6.56 pg/mL). IL-35 mRNA levels were positively correlated with plasma IL-35 levels (EBI3, R = 0.925, p < 0.01; p35, R = 0.916, p < 0.01). Furthermore, IL-35 expression levels were associated with lymph node metastasis (p = 0.001) and late tumor stage (p = 0.002). For the resected patients, high IL-35 expression levels were associated with large tumor size (p < 0.01), higher TNM classification T staging (p < 0.05), and late tumor stage (p < 0.05). In conclusion, circulating IL-35 in PDAC patients significantly increased, suggesting that regulating the expression of IL-35 may provide a new possible target for the treatment of PDAC patients, especially for the resectable ones.     

Correlation of changes in pain intensity with synovial fluid adenosine triphosphate levels after treatment of patients with osteoarthritis of the knee with high-molecular-weight hyaluronic acid

We sought to determine whether a clinical association exists between osteoarthritis (OA)-associated knee pain and adenosine triphosphate (ATP) levels in synovial fluid (SF). A total of 28 patients with 28 primary OA knees were included. They routinely received intra-articular injection of high-molecular-weight hyaluronic acid (HA) once weekly for 5 weeks (treated group). Eight patients without knee pain who had undergone an operation for anterior or posterior cruciate ligament reconstruction 2 years ago were also examined (control group). SF and blood ATP concentrations, total amount of ATP, total SF volume, and Visual Analogue Scale (VAS) scores in all patients were measured and we compared pre-treatment values with those 1 week after the final treatment. We evaluated the correlation of change in total ATP (??ATP) and change in VAS score (??VAS), ??VAS and change in SF volume (??SF), and ATP concentration in SF and blood. In the treated group, SF ATP concentration, total amount of ATP, SF volume, and VAS score were all significantly lower post-treatment than pre-treatment (p = 0.0005, 0.0003, 0.0022, and < 0.0001, respectively). In treated group, ??VAS was significantly associated with ??ATP (r = 0.56, p = 0.0032), ??SF was significantly associated with ??VAS (r = 0.78, p < 0.0001), and total amount of SF ATP and SF volume at pre-treatment were significantly higher than the control group (p < 0.0001, p < 0.0001) We demonstrated an association between SF ATP level changes and OA knee pain, which should facilitate a further understanding of OA pain mechanisms.     

Pathway analysis of genome-wide association study on asthma

Objective

The aims of this study were to identify the candidate causal single nucleotide polymorphisms (SNPs) and candidate causal mechanisms of asthma and to generate SNP to gene to pathway hypotheses.

Methods

SNPs that met a threshold of p ? 0.001 in a genome-wide association study (GWAS) dataset of asthma, which included 292,443 SNPs in 473 asthma cases and 1892 controls, were used in the present study. Identify candidate causal SNPs and pathway (ICSNPathway) analysis was applied to this dataset.

Results

ICSNPathway analysis identified four candidate causal SNPs, four genes, and 21 candidate causal pathways, which in total provided four hypothetical biologic mechanisms: (1) rs7192 (nonsynonymous coding) to HLA-DRA to 21 pathways, such as, the role of eosinophils in the chemokine network of allergy, Th1/Th2 differentiation, and asthma (nominal p ? 0.001, FDR p ? 0.01); (2) rs20541 (nonsynonymous coding) to IL13 to asthma and cytokines and inflammatory response (nominal p < 0.001, FDR p ? 0.008); (3) rs1058808 (frameshift coding) to ERBB2 to transmembrane receptor activity (nominal p = 0.001, FDR p = 0.01); (4) rs17350764 (nonsynonymous coding (deleterious)) to OR52J3 to transmembrane receptor activity (nominal p = 0.001, FDR p = 0.01).

Conclusion

By applying ICSNPathway analysis to asthma GWAS data, we found four candidate causal SNPs, four genes involving HLA-DRA and IL-13, and four hypotheses, which may contribute to asthma susceptibility.     

Postural control in isometric ramp pushes: the role of Consecutive Postural Adjustments (CPAs)

Postural adjustments, which occur after the end of a voluntary movement (termed Consecutive Postural Adjustments: CPAs), were studied and compared to the corresponding Anticipatory Postural Adjustments (APAs). Seven right-handed male adults were asked to perform horizontal two-handed maximal ramp pushes as quickly as possible, while sitting. A dynamometric bar measured the reaction to push force (F_x) and a custom-designed device measured the resultant reaction forces along the antero-posterior axis (R_x). Two ischio-femoral contacts (100 BP: full ischio-femoral contact of the ischio-femoral length; and 30 BP: one-third contact) were considered. Each session consisted of ten pushes. The reaction forces, as well as push force, increased continuously, displaying similar time course profiles. However, R_x continued to increase after the end of push rise, which ascertained CPAs. CPAs were showed to be consistent kinetic phenomena, using a biomechanical analysis, based on time courses of reaction forces and CoG kinematics. Their coherence was checked precisely, by comparing theoretical and experimental occurrences of remarkable points (extrema and zero crossings). CPA durations and peak amplitudes (dCPA and pCPA) were significantly greater than the corresponding APA values (dAPA and pAPA). Moreover, dAPAs and dCPAs increased (p < 0.001), as did pCPAs (p < 0.001) and pAPAs (p < 0.05) when the peak push force was greater (30 BP), showing that the probability of finding a statistically significant difference is greater for APA duration than amplitude, unlike CPAs. Finally, the present results were discussed in relation to the hypothesis according to which the focal and the postural components are parts of the same motor program.     

Differential alterations of GABA(A) receptor (α1, β2, γ2 subunit) expression and increased seizure susceptibility in rat offspring from morphine-addicted mothers: beneficial effect of dextromethorphan

Recent study demonstrated a close relationship between cerebellum atrophy and symptom severity of pediatric maltreatment-related posttraumatic stress disorder (PTSD). It has also been known that females are more vulnerable than males in developing anxiety disorders after exposure to traumatic stress. The mechanisms are unknown. Because cannabinoid receptors (CB₁ and CB₂) are neuroprotective and highly expressed in the cerebellum, we investigated cerebellar CB expression in stressed rats. Young male and female Sprague-Dawley rats were given 40 unpredictable electric tail-shocks for 2 h daily on 3 consecutive days. CB₁ and CB₂ mRNA and protein levels in rat cerebellum and brain stem were determined using quantitative real-time PCR and Western blot, respectively. Two-way ANOVA revealed significant gender and stress effects on cerebellar CB₁ mRNA expression, with females and non-stressed rats exhibiting higher CB₁ mRNA levels than the males (3 fold, p < 0.01) and stressed rats (30%, p < 0.01), respectively. CB₁ and CB₂ mRNA levels in brain stem were also greater in female rats than males (p < 0.01, p < 0.05, respectively). Repeated stress increased the level of phosphorylated CB₁ receptors, the inactivated CB₁, in rat cerebellum (p < 0.01), particularly in female rats as revealed by the significant gender × stress interaction. Thus, repeated severe stress caused greater CB₁ mRNA suppression and CB₁ receptor phosphorylation in female cerebellum that could lead to increased susceptibility to stress-related anxiety disorders including PTSD.