Fig. 1. Store-operated Ca2+entry in airway smooth muscle. After a wash in Hanks balanced salt solution (HBSS), extracellular Ca2+([Ca2+]o) was removed, and in the presence of nifedipine and KCl (to inhibit Ca2+influx via voltage-gated channels), the sarcoplasmic reticulum Ca2+adenosine triphosphatase inhibitor cyclopiazonic acid (CPA) was used to deplete Ca2+stores as described previously. 8,9 [Ca2+]owas then reintroduced to activate store-operated Ca2+entry. To examine the effect of volatile anesthetics and/or cell-permeant agents that increase cAMP (dibutryl cAMP [dbcAMP]) or cGMP (8-Br-cGMP), these agents were introduced after sarcoplasmic reticulum depletion and during reintroduction of [Ca2+]o. [Ca2+]; = intracellular Ca2+concentration.