Regulation of bladder and colon--rectum in patients with spinal lesions

Parasympathetic cholinergic stimulation is excitatory for bladder and colon--rectum, normal as well as uninhibited. This is documented by pharmacological and neuroanatomical studies in man. The bladder and the left half of colon and rectum have motor supply in common as demonstrated by surgical intervention on sacral nerves. More detailed studies can be performed by electrical stimulation of sacral roots or rootlets. Sympathectomy may cause alteration of voiding pattern, but often only temporarily, and generally with no alteration of defecation habits. The sympathetic innervation is sparse in the human bladder, but alpha- and beta-adrenergic receptors have been demonstrated. The alpha-adrenergic blocking agent thymoxamine is able to cause a shift in the cystometrogram to the right, and to relax the spastic pelvic sphincters by i.v. administration. Like other alpha-adrenergic blocking agents, it can relax the proximal part of the urethra. The effect of other stimulating and blocking adrenergic compounds are reported, but further studies are needed. No simultaneous reactions are generally recorded in the uninhibited bladder and rectum, and no correlation was found between the hyperactivity of the uninhibited neurogenic bladder and colon.