Effects of hydrochloric, valeric, and other volatile fatty acids on pathogenesis of ulcers in the nonglandular portion of the stomach of horses.
OBJECTIVE
To identify in vitro effects of hydrochloric acid, valeric acid, and other volatile fatty acids (VFAs) on the pathogenesis of ulcers in the nonglandular portion of the equine stomach.


METHODS
Gastric tissues from 13 adult horses.


METHODS
Nonglandular gastric mucosa was studied by use of Ussing chambers. Short-circuit current (Isc) and potential difference were measured and electrical resistance and conductance calculated after tissues were bathed in normal Ringer's solution (NRS) or NRS and hydrochloric, valeric, acetic, propionic, and butyric acids. Treated tissues were examined histologically.


RESULTS
Incubation in 60mM valeric acid at pH < or = 7.0 abruptly and irreversibly abolished Isc, which was followed by a slower decrease in resistance and an increase in conductance. Incubation in 60mM acetic, propionic, and butyric acids and, to a lesser extent, hydrochloric acid at pH < or = 7.0 significantly decreased Isc, which was followed by an increase in resistance and a decrease in conductance.


CONCLUSIONS
Incubation in valeric acid at pH < or = 7.0 caused a dramatic decrease in mucosal barrier function in the nonglandular portion of the stomach. Changes in barrier function attributable to exposure to valeric acid were associated with histopathologic evidence of cellular swelling in all layers of the nonglandular mucosa. Because of its high lipid solubility, valeric acid penetrates the nonglandular gastric mucosa, resulting in inhibition of sodium transport and cellular swelling. Valeric acid and other VFAs in gastric contents may contribute to the pathogenesis of ulcers in the nonglandular portion of the stomach of horses.
Nadeau
Jenifer A
JA
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
Andrews
Frank M
FM
Patton
Clark S
CS
Argenzio
Robert A
RA
Mathew
Alan G
AG
Saxton
Arnold M
AM
D000818:Animals; D046508:Culture Techniques; D004553:Electric Conductivity; D005232:Fatty Acids, Volatile / Q000009:adverse effects*; D005260:Female; D006734:Horse Diseases / Q000503:physiopathology; D006736:Horses; D006851:Hydrochloric Acid / Q000009:adverse effects*; D006863:Hydrogen-Ion Concentration; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D010421:Pentanoic Acids / Q000009:adverse effects*; D012964:Sodium / Q000378:metabolism; D013270:Stomach / Q000187:drug effects* / Q000473:pathology; D013276:Stomach Ulcer / Q000139:chemically induced* / Q000473:pathology / Q000662:veterinary*; D013997:Time Factors
D005232:Fatty Acids, Volatile; D010421:Pentanoic Acids; D012964:Sodium; C038780:n-pentanoic acid; D006851:Hydrochloric Acid