Intestinal dysfunction is well known after narcotic analgesics and anaesthetics. The site and extent of this action is not really known in man. We investigated the direct effect of morphine, thiopentone and droperidol on human taenia libera in vitro. The spontaneous motility of strips of fresh resected human taenia libera induced by a suitable preload was observed by isometric measurement of developed tension. Cumulative doses of morphine 1 X 10(-8) - 3.89 X 10(-6) g/ml, thiopentone 2.5 X 10(-6) - 9.75 X 10(-5) g/ml or droperidol 2.5 X 10(-8) - 9.72 X 10(-6) g/ml were added to the bath solution. The following parameters were analysed: amplitude, frequency and performance (Montevideo Units MU) of the spontaneous contractions and also the basal tone between contractions. Morphine showed no effects. Thiopentone reduced basal tone to 45.5% of the initial value and frequency to zero. The amplitude of contractions and the MU decreased with thiopentone more than 22.5 X 10(-6) g/ml. All effects are reversible. Droperidol has no significant effects with the exception of a light increase of frequency in high doses. The well known in vivo effect of morphine is therefore not induced by direct action on the smooth muscle of human intestine. Thiopentone in high dose can reduced intestinal motility by direct action on the smooth muscle. Droperidol in the dose used is probably without clinical relevance.
A Rothhammer, E Schmidt, H P Bruch