Summary
STRIPS of bovine tracheal smooth muscle were subjected to changes in the gas tensions of the Krebs solution bathing them. Contractions were produced by 50 Hz sine-wave electrical field stimulation, either in single bursts, or repetitively throughout the experiment.
Hypoxia (Po2 99, 55 or 22 mm Hg, pH 7.4) decreased the response to single bursts of stimuli by 22–56 per cent (P<0.01). Hypoxia also reduced the resting tension by 72 per cent (P<0.005). All changes due to altered gas tensions were, at least partially, reversible by returning the tissue to standard conditions.
Hypercapnic acidosis (Pco2 140–150 mm Hg, pH 6.7–7.0) reduced the response to single bursts of stimuli by 6 per cent (P<0.01) and reduced the response to repetitive bursts of stimuli by 16 per cent (P<0.01). Acapnic alkalosis (Pco2 0 mm Hg, pH 7.9) did not significantly alter the response to repetitive stimulation.
It is concluded that hypoxia, and to a lesser extent hypercapnia, can directly modify tone in the airways, and may contribute to regulation of airflow in the tracheobronchial tree.
Similar content being viewed by others
References
Astin, T. W., Barer, G. R., Shaw, J. W. and Warren, P. M. 1973. The action of carbon dioxide on constricted airways. J. Physiol. 235, 607.
Crouch, C. N. and Kirkpatrick, C. T. 1974. Some effects of altered gas tensions on the contractile behaviour of tracheal smooth muscle. Ir. J. med. Sci. 143, 187.
Daly, M. de Burg, Lambertsen, C. J. and Schweitzer, A. 1953. The effects upon the bronchial musculature of altering the oxygen and carbon dioxide tensions of the blood supplying the brain. J. Physiol. 119, 292.
Detar, R. and Bohr, D. F. 1972. Contractile responses of isolated vascular smooth muscle during prolonged exposure to anoxia. Am. J. Physiol. 222, 1269.
Detar, R. and Gellai, M. 1971. Oxygen and isolated vascular smooth muscle from the main pulmonary artery of the rabbit. Am. J. Physiol. 221, 1791.
Green, M. and Widdicombe, J. G. 1966. The effects of ventilation of dogs with different gas mixtures on airway calibre and lung mechanics. J. Physiol. 186, 363.
Kroeger, E. 1968. Mechanical and electrophysiological properties of airway smooth muscle and the effect of hypoxia. M.Sc. Thesis. Winnipeg: University of Manitoba.
Kroeger, E. and Stephens, N. L. 1971. Effect of hypoxia on energy and calcium metabolism in airway smooth muscle. Am. J. Physiol. 220, 1199.
Nadel, J. A. and Widdicombe, J. G. 1962. Effect of changes in gas tensions and carotid sinus pressure on tracheal volume and total lung resistance to airflow. J. Physiol. 163, 13.
Nisell, O. L. 1951. The action of oxygen and carbon dioxide on the respiratory movements of isolated perfused lungs. Acta physiol. Scand. 23, 352.
Scott, A. C. 1968. The effect of metabolites on the contractile behaviour of vascular smooth muscle. M.D. Thesis, The Queen’s University of Belfast.
Severinghaus, J. W. and Stupfel, M. 1955. Respiratory dead space increase following atropine in man, and atropine, vagal or ganglionic blockade and hypothermia in dogs. J. appl. Physiol. 8, 81.
Severinghaus, J. W., Swenson, E. W., Finley, T. N., Lategola, M. J. and Williams, J. 1961. Unilateral hypoventilation produced in dogs by occluding one pulmonary artery. J. appl. Physiol. 16, 53.
Smith, D. J. and Vane, J. R. 1966. Effects of oxygen tension on vascular and other smooth muscle. J. Physiol. 186, 284.
Sollman, T. and Gilbert, A. J. 1937. Microscopic observations on bronchiolar reactions. J. Pharmac. exp. Ther. 61, 272.
Stephens, N. L. and Bromberger-Barnea, B. 1969. Length-tension relationships of pulmonary artery and effects of carbon dioxide. J. appl. Physiol. 27, 266.
Stephens, N. L. and Chiu, B. S. 1970. Mechanical properties of tracheal smooth muscle and effects of O2, CO2 and pH. Am. J. Physiol. 219, 1001.
Stephens, N. L. and Kroeger, E. 1970. Effect of hypoxia on airway smooth muscle mechanics and electrophysiology. J. appl. Physiol. 28, 630.
Stephens, N. L., Meyers, J. L. and Cherniack, R. M. 1968. Oxygen, carbon dioxide, H+ ion and bronchial length-tension relationships. J. appl. Physiol. 25, 376.
Swenson, E. W., Finley, T. N. and Guzman, S. V. 1961. Unilateral hypoventilation in man during temporary occlusion of one pulmonary artery. J. clin. Invest. 40, 828.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Crouch, C.N., Kirkpatrick, C.T. Smooth muscle from the respiratory tract: Effects of altered gas tensions. IJMS 144, 157–165 (1975). https://doi.org/10.1007/BF02939006
Issue Date:
DOI: https://doi.org/10.1007/BF02939006