[Action of calcium antagonists on ureteral dynamics]

We have investigated the action, in vivo, of a calcium antagonist on pyelouretheral dynamics. A surgical model consisting of a bilateral subcutaneous nephrostomy was used, which permits repeated studies in the same animal and simultaneous collection from both pyelouretheral tracts. Anterograde perfusion of a 1.5 ml/min flow gives rise to 7.6 +/- 2.3 contractions per minute of variable amplitude between 12.4 +/- 5.6 mm Hg. Verapamil, in intravenous 5-mg application, significantly reduces (P less than 0.05) the number of contractions per minute but does not mitigate or block the stimulus to a subsequent Norepinefrina injection. We conclude that Verapamil has a moderate but significant effect on pyelouretheral dynamics. We comment on the effect that this drug may have on the pyelouretheral tract when used for hemodynamic purposes and on its potential use in various urological affections.