Fig. 3.

Inhibition of ENS by TTX reduces cAMP-stimulated I_sc in the colon. A: representative recording of I_sc responses to forskolin (FSK) and bumetanide (Bumet) in a rat distal colon segment. Following additions of 500 nM forskolin to mucosal and serosal solutions, 100 μM of bumetanide was added to serosal solution to inhibit the Na⁺/K⁺/2Cl⁻ cotransporter, as indicated. B: quantitation of forskolin-stimulated I_sc responses in proximal and distal colons. C: representative tracing of I_sc responses in a rat distal colon segment to TTX under forskolin-stimulated condition. Following additions of 500 nM forskolin to mucosal and serosal solutions, 2 μM TTX was added to serosal solution, as indicated. D: quantitation of I_sc responses to TTX under forskolin-stimulated condition in the proximal and distal colons.