Phylogenetic study on distribution and chromogranin/secretogranin content of histamine immunoreactive elements in the gut.

The distribution of histamine-immunoreactive (HA-IR) elements and possible coexistence of chromogranin A (CgA), chromogranin B (CgB) and secretogranin II (SgII) were immunohistochemically studied in gut specimens of various vertebrate species. In fish, HA-IR cells were distributed mainly within the gastric and duodenal mucosa, and nerve fibres in the gastric myenteric plexus. Only the gastric HA-IR cells co-stored SgII. In frog specimens, HA-IR endocrine cells and nerve fibres were found in the distal stomach wall, but SgII coexisted only in the nerve fibres. In lizard, HA-IR endocrine cells were widely distributed from the oesophagus to the small intestine, but only those in the stomach co-stored CgA, CgB and SgII. In chick, HA-IR cells were found in the proventriculus and almost all co-stored all three proteins. In rat, HA-IR cells were accumulated in the oxyntic mucosa and all of them constantly immunostained for CgA only.