[Mechanisms of ureteral contraction-relaxation in nephritic colic]

From the clinical perspective, pharmacological research on ureteral dynamics--the contraction-relaxation mechanisms of the ureter--, has been prompted by renal colic. Studies of the events triggered by the calculus have been conducted to identify the pharmacological aspects that permit pain relief, passage of the calculus and protection of the kidney from injury caused by acute obstruction.

Many and varied studies on ureteral pharmacology, both in vivo and in vitro, have been carried out since the beginning of the 20th century. Numerous studies on the anatomical, neurophysiological and hormonal aspects, and different neuroactive substances have attempted to identify the behavior of the ureter under normal and pathological conditions. Since 1967, the Urology Department of the 'Jiménez Díaz' Foundation has investigated the mechanisms of ureteropelvic dynamics utilizing techniques developed at this institution, such as pyelomanometry, pressure/flow to constant pressure studies and antegrade pyelography.

The different behavior of the ureter and the stimuli it receives according to the zone analyzed, are known. The classical neurohumoral mechanisms (adrenergic and cholinergic), ureteral pacemaker, effects of urinary pH and infection, action of glucagons, prostaglandins, as well as the new mechanisms of action mediated by substances and non-adrenergic non-cholinergic (NANC) receptors (tachykinins, nitric oxide (NO), vasoactive intestinal peptide (VIP), neuropeptide Y, etc.) have led to new concepts of ureteral contraction-relaxation.

The current therapeutic strategy in renal colic utilizes non-steroidal antiinflammatory drugs (NSAID) and extracorporeal shock wave lithotripsy (ESWL) in situ for analgesia and resolution. Recent insight into ureteral dynamics attempt to promote the development of new drugs for enhanced and more effective management of renal colic.