Transient increase of blood histamine level induced by pentagastrin. Continuous monitoring by in vivo microdialysis.

BACKGROUND

Since few studies of (penta)gastrin-induced histamine release from the gastric mucosa into blood has been performed, an effect of pentagastrin on histamine level of rat blood was examined by using the in vivo microdialysis method.

METHODS

Pentagastrin was perfused through the microdialysis probe implanted into the jugular vein of urethane-anesthetized rats or in urethane-anesthetized, totally gastrectomized rats, and dialysis samples of blood were concurrently collected. Histidine decarboxylase (HDC) activities and histamine contents in the glandular stomach and gastric acid output after pentagastrin stimulation were also investigated.

RESULTS

Pentagastrin induced a transient increase of blood histamine in a dose-dependent manner but failed to cause any increase of blood histamine in the totally gastrectomized rat. Pentagastrin also induced increases of the HDC activity in the glandular stomach and of the gastric acid output. The peak histamine level in blood occurred 40 min after pentagastrin perfusion, whereas the peak acid secretion occurred after 80-120 min and then leveled off.

CONCLUSIONS

The transient increase of blood histamine induced by pentagastrin is attributable to the histamine released from enterochromaffin-like cells and could be monitored by using the in vivo microdialysis method.