Abstract
The effect of buprenorphine on the interdigestive myoelectric complex (IMC) was studied by gastrointestinal electromyogram in 3 mature mongrel dogs. The electromyo-grams were used to study the IMC cycle and total elapsed time (TET).
Buprenorphine had very strong hyperkinetic action on the gastointestinal tract at doses of 1 and 2μg/kg which revealed phasic contraction, but since this action disappered when atropine was administered. The phasic contraction originated in the upper jejunum just under the ligament of Treitz and then showed a migration pattern of J → D and J → I in 11 out of 23 cases (47.8%), D → J → I in nine cases (39.1%), J → D → J → I in one case and no response in two cases. TET (min) showed a mean value of 90.3± 11.2 (n=23), which was not significantly different from the controls (106.1±14.3) (n=24), but tended to be longer (0.1>p>0.05). After administration of buprenorphine at a dose of 20, μg/kg, phasic contraction migrated to ileum, which was disappered an interval of 6-7 hours until next IMC. At low doses of buprenorphine were administered after a meal, the postprandial pattern was restored and converted to fasted pattern only one IMC cycle.
Buprenorphine is partial agonist for the μ receptor. Ahmad et al.(1989) reported that α2 adrenergic receptor and opiate receptors (mainly μ) were presented in submucosal plexus. In concludes that α2 adrenergic activity and other humoral factors seems to take an important role for the initiation of phasic contraction and to control maintenance of IMC cycle.
