Figure 7 .
Tracings of electrically induced responses of rat sham operated, one week, and four weeks bypassed ileum. Stimulation (20 Hz, 4 V, 400 mA) was maintained for five seconds (indicated by vertical bars). The contractile response elicited by electrical stimulation of sham operated ileum consists of a fast cholinergic twitch followed by a slower non-adrenergic, non-cholinergic (NANC) mediated contraction; in the bypassed ileum an identical biphasic contraction is elicited; however, the entire response was NANC mediated—that is, not blocked by atropine. After precontraction by PGF2α and in the presence of atropine a relaxation followed by a contraction is elicited by EFS. The EFS induced relaxatory response in sham operated ileum is abolished by L-NAME and thus, NO mediated. After bypass the relaxation was unaffected by pretreatment with L-NAME.