Objective    To investigate the expression changes of histidine decarboxylase (HDC) and H

+

K

+

-ATPase in gastric mucosa during the healing of experimental gastric ulcer in rats.     Methods    The ulcers were caused by applying acetic acid to the serosal surface of the anterior face of the rat gastric body. At different time points during ulcer healing

HDC and H

+

K

+

-ATPase mRNA and protein expressions were studied by using reverse transcription-polymerase chain reaction and W

estern blot respectively.     Results    An ulcer crater developed on the anterior face of the gastric body on day 1 after the induction of ulcers

and the ulcer area was biggest on day 3. On day 12

most of the gastric ulcers had healed. Compared with the control group

the HDC and H

+

K

+

ATPase mRNA expression in the gastric mucosa of ulcer rats showed a decrease on day 1

and increased back to initial level on day 9. The protein expression of HDC and H

+

K

+

-ATPase in gastric mucosa of ulcer rats decreased immediately on day 1

more on day 6

and returned to the initial levels on day 12.     Conclusion    The mRNA and protein expressions of HDC and H

+

K

+

-ATPase decrease in the healing process of gastric ulcers

resulting in accelerated ulcer healing through inhibiting gastric acid secretion.