Respiratory physiology & neurobiology
-
Respir Physiol Neurobiol · Jun 2014
Randomized Controlled TrialAntagonism of substance P and perception of breathlessness in patients with chronic obstructive pulmonary disease.
The objective of this study was to investigate whether substance P, an excitatory neuropeptide, modulates the perception of breathlessness by administering aprepitant, a selective antagonist that blocks neurokinin (NK)-1 receptor signaling. Individual targeted resistive load breathing (RLB) was used to provoke breathlessness. In Study 1, sixteen patients (age, 70±6 years) with chronic obstructive pulmonary disease (COPD) reported similar ratings of breathlessness during RLB between oral aprepitant (125mg) and placebo. ⋯ Nine patients with COPD reported comparable breathlessness ratings during RLB between aprepitant and placebo. Our results do not support a role for the substance P-NK-1 pathway in the perception of breathlessness in patients with COPD. With selective antagonism of NK-1 signaling, there was co-transmission of substance P and beta-endorphin neuropeptides.
-
Respir Physiol Neurobiol · Feb 2014
Randomized Controlled TrialEffect of rostral fluid shift on pharyngeal resistance in men with and without obstructive sleep apnea.
Obstructive sleep apnea (OSA) relates to overnight rostral fluid shift, possibly because fluid accumulation around the pharynx increases pharyngeal resistance (Rph). We hypothesised that Rph will increase more in men with than without OSA in response to rostral fluid redistribution. ⋯ OSA patients have increased susceptibility to pharyngeal obstruction in response to rostral fluid redistribution, which could predispose to pharyngeal collapse during sleep.
-
Respir Physiol Neurobiol · Dec 2013
Randomized Controlled TrialOleanolic acid improves pulmonary morphofunctional parameters in experimental sepsis by modulating oxidative and apoptotic processes.
We compared the effects of oleanolic acid (OA) vs. dexamethasone on lung mechanics and histology, inflammation, and apoptosis in lung and distal organs in experimental sepsis. Seventy-eight BALB/c mice were randomly divided into two groups. Sepsis was induced by cecal ligation and puncture, while the control group underwent sham surgery. 1h after surgery, all animals were further randomized to receive saline (SAL), OA and dexamethasone (DEXA) intraperitoneally. ⋯ However, only animals in the DEXA group had lower levels of interleukin (IL)-6 and KC (murine analog of IL-8) in bronchoalveolar lavage fluid than SAL animals. Conversely, OA was associated with lower inducible nitric oxide synthase expression and higher superoxide dismutase than DEXA. In the experimental sepsis model employed herein, OA and DEXA reduced lung damage and distal organ apoptosis through distinct anti-inflammatory mechanisms.
-
Respir Physiol Neurobiol · Feb 2013
Randomized Controlled TrialExertional acidotic responses in idiopathic pulmonary fibrosis: the mechanisms of exertional dyspnea.
To understand the mechanism of exertional dyspnea, we postulated that, despite hyperoxia during exercise, patients with idiopathic pulmonary fibrosis (IPF) might not regulate exertional acidosis by ventilatory compensation to stop exercise. The exercise responses during 30% O(2) or compressed air (CA) were examined in 13 patients with IPF. The PaO(2), PaCO(2), and HCO(3)(-) levels were higher during exercise with hyperoxia than with CA. ⋯ The dyspnea-ratio (%) of the ΔV(O(2)) (peak minus resting oxygen uptake) curve reached a break point that occurred at a similar exercise point with hyperoxia and CA, preceded by a break point in the breathing frequency-ratio of the ΔV(O(2)). Accordingly, the dyspnea score and pH each reached similar levels with hyperoxia and CA to stop exercise. Regardless of breathing CA or 30% O(2), IPF patients did not regulate exertional acidosis by ventilatory compensation to stop exercise, resulting in reaching a specific pH.
-
Respir Physiol Neurobiol · Aug 2010
Randomized Controlled Trial Clinical TrialReversibility of inspiratory lung function parameters after short-term bronchodilators in COPD.
The responsiveness of short-term bronchodilator use on inspiratory lung function parameters (ILPs), including Forced Inspiratory Volume in one second (FIV(1)), Inspiratory Capacity (IC), Forced Inspiratory Flow at 50% of the vital capacity (FIF(50)), Peak Inspiratory Flow (PIF) and on the relationship between these values and dyspnea in COPD subjects has been examined only sparsely in past studies. The aim of this study was to assess the effects of inhaled salbutamol 400 mcg, ipratropium 80 mcg and a placebo on ILP and FEV(1) and their relationship to dyspnea, as measured with a Visual Analogue Scale (VAS). ⋯ In subjects with COPD, all ILP, FEV(1) values and VAS scores showed significant improvements after bronchodilator use as well as with placebo. However, ILPs were not more sensitive than FEV(1) for detecting responders after bronchodilator use or changes in the VAS score.