Basal and pentagastrin-stimulated gastric secretion in young horses.

This research investigated gastric secretions in young horses, both at rest and following the introduction of pentagastrin, a substance that stimulates gastric secretion. The study measured different components of the gastric secretions and found that horses have a significant nonparietal component that alters secretions and is enhanced by pentagastrin.

Research Methodology

• The research used a gastric cannula model to study equine gastric secretion. A gastric cannula is a tube inserted into the stomach, allowing direct measurement of gastric secretions.
• Measurements were taken in two states: during fasting (basal) and after the infusion of pentagastrin, a hormone used to stimulate the secretion of gastric acid.
• Quantities related to the stomach fluid like the secretory rate, pH level, osmolality, and electrolyte concentrations and outputs were tracked over a period of 5 hours.
• Tests were conducted to determine the most effective dosage of pentagastrin, which was found to be between 3 to 6 micrograms per kilogram per hour.

Findings

• The basal secretory rate, essentially the ‘resting’ gastric secretion rate, was found to be 278 +/- 29 ml per 15 minutes, with an average pH of 2.00 +/- 0.31.
• Following the introduction of pentagastrin, the secretory rate increased to 533 +/- 60 ml per 15 minutes, with the pH decreasing to 1.41 +/- 0.11, indicating a higher level of acidity.
• The researchers used meq/l (milliequivalents per liter) as a measure of concentration: while the basal gastric acid concentration was 38 +/- 5 meq/l, this number went up to 60 +/- 5 meq/l after pentagastrin infusion. Similarly, acid output also increased after pentagastrin infusion.
• Osmolality, a measure of concentration of solute particles in a liquid, remained hypotonic – or lower than the surrounding body fluids – in both basal and post-pentagastrin states.
• There was also an observation of high sodium concentration compared to the hydrogen ion concentration, and an increase in sodium output with pentagastrin infusion.

Conclusion

• The study found that unlike some other monogastric species (species with a single-compartment stomach), horses did not reach high acid concentrations or experience significant drops in pH levels.
• This finding implies the existence of a large nonparietal component in horses – elements other than gastric cells that secrete acid – that modifies parietal secretions, which are also increased with pentagastrin stimulation.