Mianserin potentiates responses to acetylcholine in the rat anococcygeus muscle

In the rat anococcygeus muscle, mianserin (1 and 10 muM) increased the magnitude of the maximal contractile responses to acetylcholine and carbamylcholine without affecting the maximal responses to (--)-noradrenaline. The potentiating effect of mianserin on responses to acetylcholine was maintained in the presence of 5muM phentolamine, following 6-hydroxy dopamine incubation of the tissues (1 mM for 3h) and in the presence of 1 muM nortriptyline. It is suggested that mianserin increases the sensitivity to acetylcholine by an action at the level of, or distal to, the cholinergic receptor.