- synthesised in enterochromaffin-like cells of gastric mucosa
- release stimulated by acetylcholine or gastrin
(major response to gastrin may be gastrin-stimulated histamine release)
- binds to H2 receptors on parietal cells
- acts through stimualtory G-protein to raise cAMP levels therbey
activating basal K+ and apical Cl- channels
- also inserts more H+K+ ATPases into apical membrane
- can be antagonised by cimetidine, ranitidine as treartment for gastric
ulcer
14.6.2 Histamine
| ECL cells of body of stomach |
|
| actions: to stimulate gastric acid via H2; relationship to
gastrin and ACh from vagus |
|
| pharmacology: H2 antagonists in gastric ulceration (see
9.3.3.1) |
|
|