In vivo trigonal measurements and their relationship to competence of the ureterovesical junction

An in vitro pharmacological study of the human trigone--a site of non-adrenergic, non-cholinergic neurotransmission

Muscle strips from the human detrusor and trigone were studied in vitro. The detrusor muscle contracted strongly to both cholinergic receptor stimulation with carbachol and to electrical field stimulation. There was no evidence of atropine resistance in the detrusor strips. The superficial trigone responded maximally to alpha-adrenergic receptor stimulation but also produced a significant cholinergic response. Intramural nerve stimulation in the presence of both atropine and phentolamine produced a residual non-adrenergic, non-cholinergic (NANC) response of 40% of its maximum at 5 Hz. Electrical stimulation, particularly at the lower frequencies of stimulation, produced relaxation responses in 40% of the superficial trigonal muscle strips. These relaxations were not blocked by atropine, phentolamine or propranolol, but were abolished by tetrodotoxin. The possible role of the cholinergic "input" to the superficial trigone and the importance of the NANC excitatory and inhibitory innervation in preventing vesico-ureteric reflux and and in aiding bladder neck opening is discussed.

Pathogenetic factors in vesico-ureteral reflux. A longitudinal cystometrographic study in pigs

In a cystometrographic study in 36 young pigs the importance of ageing, of the submucosal part of ureter, and of infravesical obstruction in the vesico-ureteral reflux pathogenesis was investigated. Spontaneous vesico-ureteral reflux was found in 13 of the pigs (23 ureters). As the pigs grew older, the reflux disappeared, but if an infravesical obstruction was superimposed the reflux was maintained in half of the pigs. When the intravesical submucosal ureter was unroofed, vesico-ureteral reflux was present 10 weeks later in half of the cases. If an infravesical obstruction was superimposed all the pigs had sustained reflux 10 weeks later. The reflux producing bladder pressures decreased after induction of an infravesical obstruction. This suggests irreversible damage to the valve function due to the obstruction. In conclusion, the present study confirms ageing and the valve function as important factors preventing reflux. Additionally, it stresses the importance of normal bladder urethral function in preventing reflux.