Alteration in gastric nerve fibers containing gastrin-releasing peptide in relation to the gastrin-producing cell population after truncal vagotomy in a rat model

Abstract

The fine structural alteration in the gastric nerve fibers containing gastrin-releasing peptide (GRP) was studied in relation to the dynamics of gastrin-producing cells (G-cells) after truncal vagotomy in a rat model. The circulating gastrin levels were markedly elevated from the 1st day after vagotomy and the number of G-cells with positive immunoreaction for G17 and G34(1-15) was significantly increased in the vagotomized group. On the 3rd day after vagotomy, the G-cells showed conspicuous ultrastructural changes characterized by hypertrophy of the Golgi complexes and increased numbers of secretory granules. The GRP-positive nerve fibers formed a fine network in the gastric wall and were densely distributed in the oxyntic mucosa close to the blood vessels and showing varicosities composed of either small clear or GRP-positive large vesicles containing an electron-dense core. In the oxyntic mucosa of the vagotomized rats, axonal swelling of the nerves occurred on the 3rd day, and a depletion of GRP immunoreactivity was evidenced by a markedly decreased number of large-cored vesicles on the 7th day, when the serum GRP levels were also found to be markedly elevated. These findings indicate that the alteration in gastric nerve fibers containing GRP after truncal vagotomy may be related to hypergastrinemia and antral G-cell hyperplasia in the rat gastric mucosa.

Exclusão gastroduodenal e vagotomia troncular: repercussão no peso corporal e gastrinemia- estudo experimental em ratos

“…Ainda hoje, com técnicas mais precisas para as dosagens de hormônios e dos peptídeos intestinais, estes experimentos permanecem atuais. Cada vez mais são estudados os sistemas que envolvem as fibras nervosas colinérgicas e as que contém o peptídeo liberador de gastrina (GRP), assim como a somatostatina e os peptídeos que a liberam 9 . A exclusão gástrica total proposta permite vários enfoques para a pesquisa e também elimina o efeito dos alimentos sobre o estômago, mantendo a continuidade do trato gastrointestinal.…”

“…Sabe-se que a vagotomia troncular induz à hiperplasia das células G antrais, que se desenvolve após hipocloridria prolongada e também a um aumento do número de células G, sem interferir em sua atividade, provocando um aumento da concentração de gastrina basal e pós-prandial 8 . Esta hiperplasia se deveria à ativação de células G já existentes, com alterações ultra-estruturais demonstráveis no Complexo de Golgi e retículo endoplasmático 9 . Lopasso et al 10 , em 1999, não encontraram hiperplasia destas células quando estudaram, a longo prazo, ulcerosos duodenais submetidos à vagotomia gástrica proximal.…”

Effect of cysteamine on gastric nerve fibers containing gastrin-releasing peptide in the rat

“…2s -29 For the immunohistochemical and immunoelectron microscopic study of GRP, cryostat sections 14-to 16-[,m-thick were stained by the method we reported previously. 12 The sections were treated with anti-human GRP (hGRP) rabbit serum (GP-6201), diluted 1:2000, for 24 h, followed by the use of the avidin-biotin complex method (Biotin-StreptoAvidin Immunostaining kit; BioGenex). The antiserum (GP-6201) against human GRP used in this study was produced in our laboratory and is specific to the carboxy-terminal (C-terminal) portion of hGRP.…”