|
|
||||||||
Journal of Applied Physiology, Vol 61, Issue 4 1375-1382, Copyright © 1986 by American Physiological Society
ARTICLES |
D. J. Culp and M. G. Marin
Studies of airway glands indicate a muscarinic cholinergic regulation of secretion. Because of the cellular complexity of the airways, receptor characterization in whole tissue is unfeasible. Therefore, we utilized homogenates of disaggregated gland cells isolated from cat trachea and the muscarinic antagonist [1-3H]quinuclidinyl benzilate ([3H]QNB) to characterize glandular muscarinic receptors. Receptors of isolated cells were functionally intact as assessed by carbachol (10(-4) M) stimulation of O2 consumption 86 +/- 6% (+/- SE, n = 20). Stimulation was dose dependent (mean effective concentration = 3.5 microM), inhibited by atropine [dissociation constant (KD) = 4.2 nM] but not phentolamine nor propranolol. Specific binding of [3H]QNB to cell homogenates was saturable, of high affinity (KD = 36 pM) and to a single population of receptors. Maximum binding was 58 fmol/10(6) cells or about 35,000 receptors per cell. Estimated affinities for muscarinic agents were in the micromolar range for agonists and nanomolar range for antagonists. Histamine, alpha-adrenergic, and beta-adrenergic agonists and antagonists did not inhibit specific binding. These results suggest that muscarinic receptors on tracheal gland cells are of high affinity and density.
This article has been cited by other articles:
![]() |
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] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |