Gastric Mucosal Damage Accompanying Changes in Mucin Induced by Histamine in Rats

: The present study was carried out to clarify the mechanism of histamine‐induced gastric mucosal damage in rats. Following an injection of histamine (80 mg/kg), pH dropped within 30 min. and then recovered control value (pH=4–5) 4 hr later. The decrease in mucosal mucin content and the appearance of haemorrhagic erosions followed the drop in pH. The recovery of mucosal mucin content preceded the healing of haemorrhagic erosions and pH recovery to the control level. Histamine also caused qualitative changes in corpus mucins. These qualitative changes induced by histamine were eliminated at 7 hr following the administration of histamine. It appears from the present results that increase in HCl and decrease in mucins induced by histamine bring about gastric damage.