Actions of the muscle relaxant chandonium iodide on guinea-pig ileum and vas deferens preparations

The effects of the newly synthesized neuromuscular blocking agent, chandonium iodide (17a-methyl-3beta-pyrrolidino-17a-aza-D-homo-5-androstene dimethiodide) have been investigated on guinea-pig isolated ileum and vas deferens preparations. On the ileum, chandonium (0-1-10-0 mug ml(-1); 1-6 X 10(-7) M-1-6 X 10(-5) M) had weak muscarinic receptor blocking action (pA2 is 5-7), but no antihistamine properties at the concentration tested. No evidence for anticholinesterase actions was found. On the vas deferens, chandonium (10-50 mug ml(-1); 1-6-8-1 X 10(-5) M) potentiated responses to exogenous noradrenaline; responses to electrical stimulation were potentiated only in the presence of 50 mug ml(-1) chandonium. No adrenoceptor or adrenergic neuron blockade was found. The results provide evidence that chandonium acts selectively at acetylcholine receptors and that it is more active as a nicotinic receptor antagonist than as a muscarinic receptor antagonist.