Distribution of neuropeptides, histamine content, and inflammatory cells in the ureter

Objectives. To determine the anatomic distribution of select neuropeptides (neurokinin A [NKA], substance P [SP], and bradykinin [BK]), of inflammator y cells (leukocytes and mast cells), and the histamine content in the norma l swine ureter and compare the findings with regions of increased ureteral contractility. Methods. Ureters from 10 pigs were obtained and cut into eight segments, pr oximally to distally. A portion of each ureteral segment was suspended in K rebs buffer (37 degrees C) and attached to force displacement transducers, and spontaneous contractility was measured for 30 minutes. A second portion was assayed for histamine, NKA, SP, and BK using enzyme-linked immunosorbe nt assay. A third portion was fixed in 10% buffered formalin, stained with hematoxylin-eosin, and evaluated histologically. Results. Ureteral contractility was found to be highest in the most proxima l and most distal regions of the ureter. Similarly, SP content was three ti mes greater in the proximal ureter and two times greater in the distal uret er than in the midureter (P <0.05, n = 10). The total NKA and BK content we re also higher in the proximal and distal ureter than in the midureter. Con versely, the histamine content was consistent throughout the ureter. Moreov er, no significant difference in the distribution of inflammatory cells was identified throughout the ureter. Conclusions. The anatomic distribution of NKA, SP, and BK in the ureter cor responded to regions of increased spontaneous ureteral contractility, more specifically the proximal and distal ureter. Neuropeptides may play a signi ficant role in ureteral contractility and may be a target for pharmacologic mediation during obstruction and stone passage. UROLOGY 56: 173-178, 2000. (C) 2000, Elsevier Science Inc.