Journal of Applied Physiology, Vol 65, Issue 2 700-705, Copyright © 1988 by American Physiological Society

ARTICLES

Inhibition of cholinergic neurotransmission in human airways by beta 2-adrenoceptors

K. J. Rhoden, L. A. Meldrum and P. J. Barnes
Department of Thoracic Medicine, Brompton Hospital, London, United Kingdom.

The purpose of the study was to determine whether catecholamines modulate cholinergic neurotransmission in isolated human airway smooth muscle. Bronchial rings were suspended in organ baths for isometric measurement of tension, and contractions were induced by either electrical field stimulation (EFS) or exogenous acetylcholine (ACh). Isoproterenol, epinephrine, and norepinephrine in that order of potency produced concentration-dependent inhibition of comparable responses to EFS and ACh. However a potency difference of 100-fold for isoproterenol (IC50 = 4.80 X 10(-8) M for EFS and 3.70 X 10(-6) M for ACh) and 10-fold for both epinephrine and norepinephrine was observed for inhibition of responses to EFS compared with responses to ACh. The inhibitory effects of isoproterenol on responses to EFS were prevented by propranolol and ICI 118551 (a beta 2-antagonist) but not by betaxolol (a beta 1-antagonist). Tyramine had no effect on contractions elicited by EFS. These experiments demonstrate that beta-agonists inhibit cholinergic nerve-induced contractions of human bronchi more potently than contractions induced by exogenous ACh, suggesting modulation of cholinergic neurotransmission by prejunctional beta 2-receptors.

This article has been cited by other articles:

				V. Brusasco Reducing cholinergic constriction: the major reversible mechanism in COPD Eur. Respir. Rev., December 1, 2006; 15(99): 32 - 36. [Abstract] [Full Text] [PDF]

				B. J. Proskocil and A. D. Fryer {beta}2-Agonist and Anticholinergic Drugs in the Treatment of Lung Disease Proceedings of the ATS, November 1, 2005; 2(4): 305 - 310. [Abstract] [Full Text] [PDF]

				L. Brichetto, P. Song, E. Crimi, K. Rehder, and V. Brusasco Modulation of cholinergic responsiveness through the {beta}-adrenoceptor signal transmission pathway in bovine trachealis J Appl Physiol, August 1, 2003; 95(2): 735 - 741. [Abstract] [Full Text] [PDF]

				J.M. Wraight, R.J. Hancox, G.P. Herbison, J.O. Cowan, E.M. Flannery, and D.R. Taylor Bronchodilator tolerance: the impact of increasing bronchoconstriction Eur. Respir. J., May 1, 2003; 21(5): 810 - 815. [Abstract] [Full Text] [PDF]

				R. V. DeLuca, D. R. Grimm, M. Lesser, W. A. Bauman, and P. L. Almenoff Effects of a {beta}2-Agonist on Airway Hyperreactivity in Subjects With Cervical Spinal Cord Injury Chest, June 1, 1999; 115(6): 1533 - 1538. [Abstract] [Full Text] [PDF]

				J. R. A. de Haas, J. S. Terpstra, M. van der Zwaag, P. G. E. Kockelbergh, A. F. Roffel, and J. Zaagsma Facilitatory beta 2-adrenoceptors on cholinergic and adrenergic nerve endings of the guinea pig trachea Am J Physiol Lung Cell Mol Physiol, March 1, 1999; 276(3): L420 - L425. [Abstract] [Full Text] [PDF]

				F.-X. Blanc, S. Salmeron, C. Coirault, M. Bard, E. Fadel, E. Dulmet, P. Dartevelle, and Y. Lecarpentier Effects of load and tone on the mechanics of isolated human bronchial smooth muscle J Appl Physiol, February 1, 1999; 86(2): 488 - 495. [Abstract] [Full Text] [PDF]

				H. J. Patel, M. A. Giembycz, J. E. Keeling, P. J. Barnes, and M. G. Belvisi Inhibition of Cholinergic Neurotransmission in Guinea Pig Trachea by NS1619, a Putative Activator of Large-Conductance, Calcium-Activated Potassium Channels J. Pharmacol. Exp. Ther., August 1, 1998; 286(2): 952 - 958. [Abstract] [Full Text]

				H. S. Nelson {beta}-Adrenergic Bronchodilators N. Engl. J. Med., August 24, 1995; 333(8): 499 - 507. [Full Text] [PDF]