Abstract
In the presence of tripropylsulfonium bromide (TPS) (1×10-4 g/ml), a new compound, the phasic contraction of the isolated guinea pig ileum to 5-hydroxytryptamine (5-HT) (5×10-7 g/ml) was consistently enhanced (“TPS effect”). TPS alone increased moderately the spontaneous movement of the ileum. When the contraction height was calculated as the percentage of that to 5-HT alone, such was observed in the “TPS effect” to be 167.1±3.6% (mean±S.E., n=80). TPS did not enhance the contraction due to acetylcholine or histamine. The “TPS effect” remained unaffected in the presence of dibenzyline (1×10-7 g/ml), was abolished by morphine (1×10-6 g/ml), tetrodotoxin (2×10-8 g/ml) adenosine (3×10-6 g/ml) and atropine (1×10-7 g/ml) and was not observed under anoxic conditions. Eserine (1×10-8 g/ml) strengthened the “TPS effect” markedly. It is concluded that this effect may be the result of the potentiating effect of TPS on the action of 5-HT through the M receptors, possibly by the facilitation of the acetylcholine-liberation from the nervous tissue.
