64 A. G. H. SANTOSO ET AL.
diating urothelium-dependent and urothelium-indepen-
dent detrusor phasic contractions may be useful. It is not
possible to isolate the effects of the urothelium from
those of the smooth muscle if the intravesical pressure of
the whole bladder is measured, although this method
resembles in vivo physi ol o gy more closely.
In summary, the role of individual K+ channel block-
ers in mediating phasic activity in the detrusor was ex-
amined. In measuring phasic contractions in two direc-
tions, transversely and longidutinally, differential sensi-
tivity to the K+ channel blockers was demonstrated. Pha-
sic activity in the transverse direction could be distin-
guished from that in the longitudinal direction by using
selective blockers of Kv, BK and IK channels. The dis-
covery of differential phasic activity highlights the po-
tential importance in considering the physiological func-
tion of contractility in more than one direction.
5. Acknowledgements
This study was supported by the Singapore Ministry of
Education (RG63/06 and RG83/07) and the Institute of
Advanced Studies, Nanyang Technological University,
Singapore.
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