A tonic component in the motility of the upper urinary tract (renal pelvis-ureter)

In isolated muscle strips of porcine renal pelvis and ureter, the calcium antagonist nifedipine (3·10−7 moles/l) completely suppressed spontaneous phasic mechanical activity and the phasic components of an adrenaline-induced activation (P-component). In the presence of nifedipine, adrenaline induced in pelvis preparations (but not in the ureter) a tonic contraction (T-component) which was on average 61% of the control reaction (SD±26%; n=35).