Histamine content and release of isolated rat gastric mucosal cells

Enzymatically dispersed rat gastric cells were subdivided (Percoll) in fractions (F1, F2, F3) with different number of parietal cells (PC) and the intracellular histamine content was estimated (ng/10(6) cells): F1 (9% PC): 17 +/- 4 (SEM), F2 (26% PC): 80 +/- 9 and F3 (77% PC): 134 +/- 15. Histidinedecarboxylase showed the same pattern of distribution, F1 low, F2 medium, F3 high activity. Incubated F3 cells constantly released histamine (19 +/- 3 ng/10(6) cells/h), a process which could be stimulated by carbachol, forskolin and hexoprenaline. The data suggest: rat gastric histaminocytes copurify with PC, background stimulation by histamine should be considered in isolated cell systems, vagal stimulation may release histamine within the gastric mucosa.