Ion channels in asthma

Abstract

Ion channels are specialized transmembrane proteins that permit the passive flow of ions following their electrochemical gradients. In the airways, ion channels participate in the production of epithelium-based hydroelectrolytic secretions and in the control of intracellular Ca(2+) levels that will ultimately activate almost all lung cells, either resident or circulating. Thus, ion channels have been the center of many studies aiming to understand asthma pathophysiological mechanisms or to identify therapeutic targets for better control of the disease. In this minireview, we focus on molecular, genetic, and animal model studies associating ion channels with asthma.

FIGURE 1.

Ion channels and asthma. This schematic overview of the different airway cells shows the ion channels associated with asthma pathophysiology or its clinical symptoms. See text for a detailed explanation.

FIGURE 2.

Calcium responses to activators of TRPV1 and purinergic receptors in mouse tracheal ciliated cells. Shown are average calcium increases measured with the Ca²⁺ sensor Fura-2 in a primary culture of mouse tracheal cells exposed to two different concentrations (100 nm and 1 μm) of the TRPV1 activator capsaicin. Under these conditions, ciliated epithelial cells did not respond to capsaicin but did respond to ATP (20 μm), a typical physiological activator of purinergic receptors. Results are expressed as the mean ± S.E. of 10 cells.