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‐3β‐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 μg ml⁻¹; 1·6 × 10⁻⁷m–1·;6 × 10⁻⁵m) 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 μg ml⁻¹; 1·6–8·1 × 10⁻⁶ m) potentiated responses to exogenous noradrenaline; responses to electrical stimulation were potentiated only in the presence of 50 μg 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.