Study of Nitric Oxide in Pyloric Muscles and Blood in Infants with Congenital Hypertrophic Pyloric Stenosis

Objective:To search the changes of nitric oxide (NO) in hypertrophic pyloric muscles and blood of infants with congenital hypertrophic pyloric stenosis (CHPS).Methods:The distribution of NO synthase(NOS)in the pyloric muscles was studied by nicotinamide adenine dinucleotide phosphate diaphorase(NADPHd) histochemical reaction.Twenty-one muscular specimens obtained from pyloromyotomy.and 5 specimens from infants without pyloric diease served as control group.NO level in the blood of 9 cases with CHPS and the control (26 blood samples) was measured by chromometry.Results:NADPHd activity was absent in the fibers of the hypertrophied pyloric circular muscles,and only a few nerve fibers in the longitudinal muscles and myenteric plexus.Intense NADPHd was present in the nerve fibers of circular and longitudinal muscles,the neurons and myenteric plexus of control group.There was no difference of NO levels in the blood between the two groups (P = 0.6),and no significant difference in the blood of CHPS group before and after operation(P=0.5).Conclusions;Lack of NOS in pyloric muscles may be responsible to the achalasia of pyloric sphincter and lead to pyloric obstruction while changes of NO levels in blood has no clinical significance.We infer that the pathological changes may be localized in the circular pyloric muscles. Key words: Nitric oxide; Congenital hypertrophic pyloric stenosis; Nitric oxide synthase