Rabbit sphincter of Oddi has a certain autonomy: characteristic features.

Simultaneous recordings of electromyography and manometry were obtained from rabbit sphincter of Oddi (SO) and duodenum. Three different patterns of activity were observed in SO and in duodenum: 1) a low-amplitude (less than 3 cm H2O) pattern of background oscillations with 2) superimposed high-amplitude (4-20 cm H2O) contractions and 3) occasional complex contractions consisting of an elevation of the basal pressure with superimposed smaller contractions. A certain SO autonomy was evident: 57.6% of SO pressure peaks could not be assigned to any duodenal activity. The distribution of SO pressure peak amplitudes could not be described by a simple normal distribution. The distribution of SO pressure peak amplitudes with concomitant duodenal activity differed from the overall distribution (p less than 0.001). Whereas a substantial part of SO pressure peaks greater than 4 cm H2O had no or low-amplitude corresponding duodenal pressure activity, duodenal pressure peaks greater than 4 cm H2O almost invariably were associated with SO pressure peaks. It is concluded that rabbit SO does possess a certain autonomy, but at the same time a close functional connection exists between the two compartments.