Effects of fenoterol on ventilatory responses to hypoxia and hypercapnia in normal subjects.
Open Access
- 1 February 1995
- Vol. 50 (2) , 139-142
- https://doi.org/10.1136/thx.50.2.139
Abstract
BACKGROUND--The effects of beta 2 adrenergic agonists on chemoreceptors remain controversial. This study was designed to examine whether fenoterol, a beta 2 adrenergic agonist, increases the ventilatory responses to hypercapnia (HCVR) and hypoxia (HVR) in normal subjects. METHODS--HCVR was tested with a rebreathing method and HVR was examined with a progressive isocapnic hypoxic method in 11 normal subjects. Both HCVR and HVR were assessed by the slope of occlusion pressure (P0.1) or ventilation (VE) plotted against end tidal carbon dioxide pressure and arterial oxygen saturation, respectively. Respiratory muscle strength, spirometric values and lung volume were measured. After a single oral administration of 5 mg fenoterol or placebo HCVR and HVR were evaluated. RESULTS--Fenoterol treatment did not change the specific airway conductance or forced expiratory volume in one second. Respiratory muscle strength did not change. Fenoterol increased the slope of the HCVR of both P0.1 (from 0.251 (0.116) to 0.386 (0.206) kPa/kPa, average increase 71%) and VE (from 10.7 (3.4) to 15.1 (4.2) l/min/kPa, average increase 52%), and shifted the response curves to higher values. For the HVR fenoterol increased the slopes of both P0.1 and VE (from -4.06 (2.00) x 10(-3) to -7.99 (4.29) x 10(-3) kPa/%, an average increase of 83%, and from -0.221 (0.070) to -0.313 (0.112) l/min/%, a 44.5% increase, respectively), and shifted the response curves to higher values. CONCLUSION--Acute administration of fenoterol increases the ventilatory responses to both hypercapnia and hypoxia in normal subjects.Keywords
This publication has 26 references indexed in Scilit:
- Occlusion pressure as a measure of respiratory center output cm conscious manPublished by Elsevier ,2003
- Acute effects of inhaled salbutamol on the metabolic rate of normal subjects.Thorax, 1993
- Augmentation of carotid body chemoreceptor responses by isoproterenol in the catRespiration Physiology, 1981
- Mechanisms of hyperpnea induced by isoproterenolRespiration Physiology, 1980
- Central β-Adrenergic Effects on the Control of Ventilation in CatsRespiration, 1980
- Mechanism of the isoproterenol hyperpnea in the catRespiration Physiology, 1979
- Effects of Hypermetabolism on Ventilation and ChemosensitivityJournal of Clinical Investigation, 1977
- Effect of intravenous infusion of salbutamol on ventilatory response to carbon dioxide and hypoxia and on heart rate and plasma potassium in normal men.BMJ, 1976
- Effects of adrenergic stimulation on ventilation in manJournal of Clinical Investigation, 1972
- THE EFFECT OF OBSTRUCTION TO BREATHING ON THE VENTILATORY RESPONSE TO CO21Journal of Clinical Investigation, 1956