AJP - Regulatory, Integrative and Comparative Physiology, Vol 272, Issue 5 1409-R1416, Copyright © 1997 by American Physiological Society
Effects of artificial calculosis on rat ureter motility: peripheral contribution to the pain of ureteric colic
J. M. Laird, C. Roza and F. Cervero
Department of Physiology and Pharmacology, Faculty of Medicine, University of Alcala, Madrid, Spain.
The contribution of changes in ureter motility produced by a stone to the
pain of ureteric calculosis is unclear. In this study we measured ureter
motility as changes in intraureter pressure in anesthetized rats 1, 4, and
8 d ys after implantation of an artificial calculus (n = 33) and compared
it with motility in normal (n = 8) and ligated (n = 4) ureters. Partial
obstruction of the ureter by the stone produced a 478% increase in the
amplitude of contractions, a 70% decrease in the rate of contractions, and
a 66% decrease in the baseline pressure. The pressures reached during
contractions were equivalent to those evoking nociceptive reactions in
animals and humans. These changes persisted in rats that had spontaneously
eliminated the stone. Complete obstruction of the ureter by the stone or by
ligation abolished contractions. We conclude that the increased motility
caused by a stone likely contributes to the development and maintenance of
visceral pain and referred hyperalgesia in ureteric colic and to the
persistence of referred hyperalgesia after elimination of the stone.
