Role of gastric blood flow in impaired defense and repair of aged
rat stomachs.
Gronbech, Jon Erik, and Eric R. Lacy.
Department of Cell Biology and Anatomy, Medical University of South
Carolina, Charleston, South Carolina
APStracts 2:0115G, 1995.
To study impaired gastric mucosal tolerance against noxious agents in
aged rats, possible factors underlying this observation were compared
in anesthetized Fisher 344 young and aged rats. The gastric mucosa
was damaged by in situ exposure to 80% ethanol for 30-45 seconds, and
by 1 M NaCl for 10 min followed by saline (pH=1.0) for 60 min in
chambered stomachs. Lesion area was significantly larger and
epithelial restitution significantly slower in aged than in young
rats after both types of injury. Changes in gastric blood flow were
monitored by laser Doppler velocimetry. Young, but not aged rats,
showed a marked increase in gastric blood flow in response to 1 M
NaCl, acid challenge, and capsaicin 640 [mu]M for 60 min. Young rats
showed higher density of CGRP staining nerve fibers around submucosal
blood vessels, and higher mucosal release of prostaglandin E2 and
leukotriene C4 than did aged rats. These data suggest that impaired
mucosal defense and, reduced restitution in aged rats is related to
lack of hyperemic response caused by mucosal injury, and H+ back
-diffusion, which is probably due to decreased density of CGRP
staining nerve fibers and prostaglandin biosynthetic capacity in the
mucosa.
Received 10 January 1995; accepted in final form 24 May 1995.
APS Manuscript Number G15-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.