Age-dependent Regulation of Sodium-potassium Adenosinetriphosphatase and Sodium-hydrogen Exchanger mRNAs in Equine Nonglandular Mucosa

Amanda L. Peretich, University of Tennessee - Knoxville
Lora L. Abbott, University of Tennessee - Knoxville
Frank M. Andrews, Louisiana State University and Agricultural & Mechanical College
Madhu S. Dhar, University of Tennessee, Knoxville

Abstract

Abstract American Journal of Veterinary Research September 2009, Vol. 70, No. 9, Pages 1124-1128 doi: 10.2460/ajvr.70.9.1124

Age-dependent regulation of sodium-potassium adenosinetriphosphatase and sodium-hydrogen exchanger mRNAs in equine nonglandular mucosa Amanda L. Peretich, MS; Lora L. Abbott, BS; Frank M. Andrews, DVM, MS; Madhu S. Dhar, PhD Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996. (Peretich, Abbott, Dhar); Equine Health Studies Program, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803. (Andrews) Supported by grants from the University of Tennessee, Centre of Excellence in Livestock Disease and Human Health.

Presented in part at the 9th International Equine Colic Research Symposium, Liverpool, England, June 2008.

Address correspondence to Dr. Dhar. Objective—To determine whether expression of mRNA for sodium-potassium adenosine-triphosphatase (NAKA) and sodium-hydrogen exchanger (NHE) in samples of the nonglandular portion of the equine gastric mucosa was altered by exposure to volatile fatty acids (VFAs) in an acidic environment.

Animals—10 horses (5 ≤ 5 years old and 5 ≥ 12 years old).

Procedures—Samples of the nonglandular portion of the gastric mucosa were collected and exposed in Ussing chambers to Ringer's solution (control samples), Ringer's solution containing a mixture of VFAs (pH, 1.5 or 4.0), or Ringer's solution containing acetic acid (pH, 1.5 or 4.0). Expression of mRNA for the gene for the β1 subunit of NAKA and the gene for the NHE-3 isoform was determined by means of real-time PCR assays.

Results—For horses ≤ 5 years old, relative expression of mRNA for NAKA was significantly decreased and expression of mRNA for NHE was significantly increased following exposure to the mixture of VFAs or acetic acid, compared with expression in control samples. In contrast, for horses ≥ 12 years old, relative expression of mRNA for both NAKA and NHE was significantly increased following exposure to the mixture of VFAs or acetic acid, compared with expression in control samples.

Conclusions and Clinical Relevance—Results suggested that relative expression of mRNA for NAKA, but not NHE, in samples of the nonglandular portion of the equine gastric mucosa in response to exposure to VFAs in an acidic environment was an age-dependent event.