Figure 3.

Summary of excitatory responses in wild-type and W/W^V fundus to electrical field stimulation (EFS). (A) Representative bar graphs of the mean values of the area under the curve (AUC; mN · sec) and (B) Representative bar graphs of the mean peak amplitudes (mN) of the contractile responses to EFS (1–32 Hz) in wild-type and both W/W^V groups 1and 2. The average AUC and peak contractile amplitudes were calculated in the presence of atropine (1 μM), N^ω-nitro-l-arginine (L-NNA, 100 μM) and in the presence of both L-NNA and atropine together from each control mice (C) and W/W^V group 1 (W1) and W/W^V group 2 (W2) fundus. Note the large increases in contraction after L-NNA in wild-type and W/W^V group 2 muscles, but very small increase in contractile responses after L-NNA in W/W^V group 1 muscles. These observations indicate that very little nitrergic regulation occurs in the absence of intramuscular interstitial cells of Cajal. Note in the bar graphs the 1 triangle indicates a P-value < 0.05, 2 triangles indicate a P-value < 0.01 and 3 triangles indicate a P-value < 0.001.