Maturational Changes in Na+-K+Pump Activity in Guinea Pig Airway Smooth Muscle

Autor: Kerry J. Rhoden, Magdalena Souhrada, James S. Douglas
Rok vydání: 1997
Předmět:
Zdroj: Experimental Lung Research. 23:333-345
ISSN: 1521-0499
0190-2148
DOI: 10.3109/01902149709039230
Popis: The effect of maturation on the Na(+)-K+ pump of airway smooth muscle (ASM) was studied. Na(+)-K+ pump activity of tracheal smooth muscle from immature (1- to 2-week-old) and mature (10- to 12-week-old) guinea pigs was measured as the ouabain-sensitive component of the resting membrane potential and as ouabain-sensitive 86Rb+ uptake (using 86Rb+ as a marker for K+). Maturation resulted in decreases in both the contribution of the Na(+)-K+ pump of the resting membrane potential and in ouabain-sensitive 86Rb+ uptake. 86Rb+ efflux from tracheal smooth muscle was similar in tissues from immature and mature guinea pigs, suggesting that maturation has no effect on K+ (or at least 86Rb+) permeability. Na+ and K+ contents of tracheal smooth muscle were estimated from the uptakes of 24Na+ and 86Rb+ at equilibrium. Maturation resulted in a decrease in Na+ content but had no effect on K+ content. Since intracellular Na+ is one of the principal determinants of Na(+)-K+ pump activity, these results suggest that maturation results in a decrease in Na(+)-K+ pump activity in ASM, which may be due to a decrease in Na+ content.
Databáze: OpenAIRE