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

Figure 4 Effect of the blockade of the BK_Ca channel with iberiotoxin (10^-7 mol/L) of lower esophageal sphincter (A) circular (n = 6-8) and (B) sling (n = 7-11) smooth muscle tone with intact nerves or blocked with tetrodotoxin (10^-6 mol/L). A: For the circular muscle, tetrodotoxin (TTX) or iberiotoxin (IbTX) did not significantly change the resting tension (P > 0.05). The combined blockade of the nerves and the BK_Ca channel also resulted in no significant change of the overall muscle tone (P > 0.05); B: Similarly, for the sling muscle, TTX, IbTX or TTX and IbTX together did not significantly modulate the basal resting tone (P > 0.05). //: Separates different experiments.