Membrane properties of bovine airway smooth muscle cells: Effects of maturation
| Autor: | Magdalena Souhrada, James S. Douglas, Karen G. Rothberg |
|---|---|
| Rok vydání: | 1988 |
| Předmět: |
Pulmonary and Respiratory Medicine
medicine.medical_specialty In Vitro Techniques Biology Muscle Development Ouabain Membrane Potentials In vivo Internal medicine medicine Animals Pharmacology (medical) General Pharmacology Toxicology and Pharmaceutics Cardiac glycoside Adenosine Triphosphatases Membrane potential Membranes Muscle Smooth Airway smooth muscle Respiratory Muscles In vitro Membrane Endocrinology Trachealis muscle Cattle Female medicine.drug |
| Zdroj: | Pulmonary Pharmacology. 1:47-52 |
| ISSN: | 0952-0600 |
| DOI: | 10.1016/0952-0600(88)90010-5 |
| Popis: | Airway smooth muscle cells of bovine trachealis muscle from immature (2 weeks old), developing (5 months old) and mature animals (greater than 5 years old) have resting membrane potentials of -63.5 +/- 0.4 mV, -62.2 +/- 0.8 mV and -60.3 +/- 0.7 mV, respectively. These resting potentials were not significantly different. The contribution of the electrogenic sodium pump to the resting membrane potential of airway smooth muscle cells decreases significantly with age being 38.3% +/- 0.9, 30.6% +/- 0.8 and 21.3% +/- 0.9 in tissues from immature, developing and mature cows, respectively. The contribution of the electrogenic sodium pump to resting membrane potential was not influenced by the degree of stretch (applied load) of the airway smooth muscle cells. However, resting membrane potential was reduced with increasing tone especially when loads between 5 to 10 g were applied. The densities of Na+/K+ pump sites, as measured by [3H] ouabain binding, decreased significantly as a consequence of maturation and were 4.12 +/- 5.23, 3.08 +/- 0.26 and 1.94 +/- 0.38 pmoles/mg protein ouabain binding in tissues from immature, developing and mature animals respectively. The affinity of the pump sites for the cardiac glycoside, ouabain, did not change during maturation. We conclude that maturation alters both the number of Na+/K+ pump sites and the contribution of the electrogenic sodium pump to the membrane potential of airway smooth muscle cells. These age related changes may contribute to the reduced airway reactivity to both bronchoconstrictor and bronchodilator agents previously observed both in vitro and in vivo. |
| Databáze: | OpenAIRE |
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