Secretagogue-induced [14C]aminopyrine uptake in isolated equine parietal cells.

This research aimed to study acid production and secretagogue response in isolated equine parietal cells using [14C]aminopyrine, and found histamine to be the most effective stimulant. However, carbachol and pentagastrin were less effective.

Research Methodology

• Equine oxyntic mucosal cells were isolated using pronase and collagenase.
• Acid production by these cells was measured using [14C]aminopyrine (AP) which is a weak base that accumulates in acidic spaces within the cells.
• Cells were incubated for different periods of time, and it was discovered that AP uptake was maximized at 10 minutes for histamine and carbachol.
• Different chemical stimulants (secretagogues) such as IBMX, carbachol, and pentagastrin (PG) were used on the cells.

Key Findings

• Histamine and isobutyl-methylxanthine (IBMX) induced a dose-dependent response in AP uptake, showing maximum efficacy at a concentration of 100 microM.
• Carbachol and PG, however, didn’t significantly stimulate AP uptake even at increased concentrations.
• The research shows uptake values for different substances in comparison to that by 100 microM histamine.
• Cells not stimulated (i.e., control cells) had an AP uptake of 36 +/- 3.6% of the maximal stimulation by histamine.
• The AP accumulation in control conditions, and in the presence of histamine, IBMX, carbachol, or PG were all calculated showing histamine had by far the greatest impact.

Conclusions

• The shift in individual histamine dose-response curves to the right by increasing ranitidine and cimetidine concentrations indicates histamine was most effective in stimulating the cells.
• The study concludes that equine parietal cells are maximally stimulated by histamine and minimally stimulated by carbachol and PG.