The effect of trifluperidol on the contractile response of guinea-pig taenia coli to acetylcholine, histamine, potassium and calcium.

In guinea-pig taenia coli, trifluperidol antagonized the contraction induced by all agonists tested in a non-competitive manner. pA2 values for trifluperidol calculated for acetylcholine, histamine and calcium were not different. pD'2 values for trifluperidol calculated for acetylcholine, histamine and potassium did not differ, while the pD'2 for acetylcholine and calcium were significantly different. pD'2 values for trifluperidol calculated for calcium varied with the concentration of the antagonist. Trifluperidol has been considered a non-specific blocking agent in guinea-pig taenia coli. This inhibitory activity has been considered very similar to that of local anaesthetic agents, although calcium was blocked in a non-competitive manner by trifluperidol, differently from anaesthetic agents that block calcium in a competitive way.