Nitric oxide activation of a potassium channel (BKCa) in feline lower esophageal sphincter

Figure 2 Pharmacological identification, with iberiotoxin (200 nmol/L), of the portion of the elicited outward K⁺ currents, using a ramp protocol from -140 to +60 mV, corresponding to BK_Ca channel currents in lower esophageal sphincter circular (n = 8) smooth muscle cells. Last 300 ms of representative traces shown. Sodium nitroprusside (SNP) induced a significant increase in elicited outward potassium currents vs control current density. Iberiotoxin (IbTX) alone blocked a significant portion of the control outward potassium currents. SNP added in the presence of IbTX, produced no significant increase in the outward currents. ^aP < 0.05.