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Maturation of acetylcholinesterase expression in tracheal smooth muscle contraction

Publication ,  Journal Article
Mitchell, RW; Murphy, TM; Kelly, E; Leff, AR
Published in: American Journal of Physiology - Lung Cellular and Molecular Physiology
1990

We examined postganglionic development of acetylcholinesterase (AChase) activity and tracheal smooth muscle (TSM) contraction elicited by cholinomimetic activation and electrical field depolarization in vitro. Epithelium-intact tracheal strips excised from 21 2-wk-old swine (2ws) and 19 10-wk-old swine (10ws) were tethered isometrically at optimal resting length, and responses were expressed as percent of the maximum to 63 mM potassium-chloride (%KCl). Cumulative concentration-response curves to KCl were equivalent for TSM from 2 and 10ws. However, maximal contraction to ACh in 2ws (168 ± 8.4 %KCl) was greater than for 10ws (142 ± 2.3 %KCl; P < 0.02). Stimulus response curves (field electrodes; AC source) demonstrated greater sensitivity for TSM in 10ws (stimulus causing 50% of the maximal response = 3.32 ± 0.13 V in 2ws vs. 2.25 ± 0.12 V in 10ws; P < 0.001), indicating that the greater cholinomimetic responsiveness of 2ws did not result from augmented presynaptic nerve conduction. The AChase inhibitor, physostigmine, caused 1) greater sensitivity of responses elicited by electrical field stimulation in 2ws (P < 0.05) but not in 10ws (P = NS), 2) augmentation of maximal responses to exogenous ACh in 10ws (27% increase; P < 0.01) but not 2ws (2% increase; P = NS), and 3) a greater increase in sensitivity to cholinomimetic activation in 2ws compared with 10ws (P < 0.02). These data demonstrate increased cholinergic contraction of TSM in 2 vs. 10ws that results at least in part from reduced AChase activity in the trachea of immature animals.

Duke Scholars

Published In

American Journal of Physiology - Lung Cellular and Molecular Physiology

Publication Date

1990

Volume

259

Issue

2 3-1

Start / End Page

L130 / L135

Related Subject Headings

  • Respiratory System
  • 1116 Medical Physiology
  • 0606 Physiology
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Mitchell, R. W., Murphy, T. M., Kelly, E., & Leff, A. R. (1990). Maturation of acetylcholinesterase expression in tracheal smooth muscle contraction. American Journal of Physiology - Lung Cellular and Molecular Physiology, 259(2 3-1), L130–L135.
Mitchell, R. W., T. M. Murphy, E. Kelly, and A. R. Leff. “Maturation of acetylcholinesterase expression in tracheal smooth muscle contraction.” American Journal of Physiology - Lung Cellular and Molecular Physiology 259, no. 2 3-1 (1990): L130–35.
Mitchell RW, Murphy TM, Kelly E, Leff AR. Maturation of acetylcholinesterase expression in tracheal smooth muscle contraction. American Journal of Physiology - Lung Cellular and Molecular Physiology. 1990;259(2 3-1):L130–5.
Mitchell, R. W., et al. “Maturation of acetylcholinesterase expression in tracheal smooth muscle contraction.” American Journal of Physiology - Lung Cellular and Molecular Physiology, vol. 259, no. 2 3-1, 1990, pp. L130–35.
Mitchell RW, Murphy TM, Kelly E, Leff AR. Maturation of acetylcholinesterase expression in tracheal smooth muscle contraction. American Journal of Physiology - Lung Cellular and Molecular Physiology. 1990;259(2 3–1):L130–L135.

Published In

American Journal of Physiology - Lung Cellular and Molecular Physiology

Publication Date

1990

Volume

259

Issue

2 3-1

Start / End Page

L130 / L135

Related Subject Headings

  • Respiratory System
  • 1116 Medical Physiology
  • 0606 Physiology