Abstract
Development of substance P-containing nerve fibers was studied in eight human fetal urinary bladders obtained from fetuses of 12 to 26 weeks gestation using monoclonal antibodies against substance P. At 12 weeks occasional fibers were seen in the trigonal submucosa and bladder wall while fine fiber plexuses, in fewer amount, were present along the blood vessels entering the bladder. Increasing proportion of thick substance P fibers were seen in 15, 19 and 26 week trigonal submucosal blood vessels and muscle layers. Occasional immunopositive fibers were also observed to enter the epithelium.
