Decreased sensitivity of muscarinic but not 5‐hydroxytryptamine receptors of the internal anal sphincter in neurogenic faecal incontinence

Abstract

Previous studies of the internal anal sphincter in patients with neurogenic faecal incontinence have indicated an abnormality of the adrenergic innervation, but little is known about the responsiveness of other receptors in the internal anal sphincter in this condition. In this study the in vitro sensitivity to carbachol and 5‐hydroxytryptamine (5‐HT) of muscle strips from patients with neurogenic incontinence (n = 6 and n = 7) and from control patients (n = 9 and n = 10) was examined. Preparations of internal anal sphincter from patients with incontinence were less sensitive to the relaxant actions of carbachol than preparations from the control group. The pD2 value for carbachol (i.e. the ..