The role of the urothelium and ATP in mediating detrusor smooth muscle contractility.
OBJECTIVE
To examine the contractility of urothelium-intact (+UE) and urothelium-denuded (-UE) rat detrusor strips under adenosine triphosphate (ATP) treatment. Purinergic signaling exists in the bladder but both the inhibitory effect of ATP on detrusor contractions and the function of urothelial ATP are not established.


METHODS
Detrusor strips were obtained from bladders of young adult rats. Isometric tension from both transverse and longitudinal contractions was measured using a myograph. The muscarinic agonist carbachol (CCh) was used to induce contractions, which were under the influences of different concentrations of ATP.


RESULTS
In both +UE and -UE strips, 1 mM ATP suppressed CCh-induced contractions. In longitudinal contractions, ATP added to the inhibitory effect of urothelium on CCh responses. Removal of the urothelium, but with exogenous ATP added, recovered the CCh responses to the same level as in +UE strips with no added ATP. Transverse contractions were less susceptible to ATP in the presence of urothelium.


CONCLUSIONS
We showed that the urothelium and ATP suppressed CCh-induced contractions to a similar extent. The findings suggest an inhibitory role of urothelial ATP in mediating detrusor smooth muscle contractility, which may be impaired in diseased bladders.
Santoso
Aneira Gracia Hidayat
AG
School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
Sonarno
Ika Ariyani Bte
IA
Arsad
Noor Aishah Bte
NA
Liang
Willmann
W
D000255:Adenosine Triphosphate / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D001743:Urinary Bladder / Q000502:physiology*; D019459:Urothelium / Q000502:physiology*
D000255:Adenosine Triphosphate; D002217:Carbachol