Ionic mechanisms underlying electrical slow waves in canine airway smooth muscle

In canine bronchial smooth muscle (BSM), spasmogens evoke oscillations in membrane potential ('slow waves'). The depolarizing phase of the slow waves is mediated by voltage-dependent Ca²⁺ channels; we examined the roles played by Cl^- and K⁺ currents and Na⁺-K⁺-ATPase activity in mediating the repolarizing phase. Slow waves were evoked using tetraethylammonium (25 mM) in the presence or absence of niflumic acid (100 μM; Cl^- channel blocker) or …