[Intramural nervous apparatus of jejunum and rectum in experimental portal hypertension]

Using histological and electron microscopical methods, the state of intramural nervous structures of jejunum and rectum was studied in 92 dogs with experimental portal hypertension. Three phases of changes of portal pressure were detected and its influence upon the intramural nervous apparatus was observed. In phase 1 (first 4-5 days after the surgery) the reactive changes of the nervous apparatus were shown that were more pronounced in jejunum. In phase 2 (day 5 to 2.5 months) the portal pressure was shown to drop; this was accompanied by some signs of regeneration in jejunum and by an aggravation of destructive processes in rectum. In phase 3 of the repeated rise of portal pressure (2.5 to 6.5 months after the surgery), destructive changes in the nervous apparatus were demonstrated that were similar to those found in phase 1. However, the differences in the reaction of nervous structures in different layers of intestinal tube and the heterogeneity of the changes of the nervous apparatus in jejunum and rectum were absent. The association of time of appearance and of severity of structural changes with the elevation of portal pressure suggests the significant role of vascular factor in the morphogenesis of alterations observed in phase 3 of hemodynamic changes.