Response of the rat ileum, uterus and vas deferens to carbachol and acetylcholine following repeated daily administration of a cholinesterase inhibitor.

1. Daily i.p. administration, for eight days, of the cholinesterase inhibitor disulfoton to rats produced mild to moderate signs of intoxication (tremors, incontinence and diarrhoea) but no deaths.2. Segments of ileum taken from the treated rats were subsensitive to carbachol but the vas deferens and the uterus did not exhibit any change in sensitivity to carbachol.3. The sensitivity to acetylcholine was increased in the ileum and vas deferens but not in the uterus.4. Acetylcholinesterase activity was 60-70% inhibited in all three tissues.