Distribution of mRNA that codes for 5-hydroxytryptamine receptor subtypes in the gastrointestinal tract of dairy cows.
OBJECTIVE
To describe the distribution of mRNA that codes for 8 subtypes of 5-hydroxytryptamine receptors (5-HTRs) in the digestive tract of dairy cows.


METHODS
Fresh full-thickness wall specimens from the abomasum (fundus, corpus, and antrum), ileum, cecum, proximal loop of ascending colon, and 4 locations of the spiral colon collected from 10 healthy cows at slaughter.


METHODS
Concentrations of mRNA that code for 5-HTR subtypes (5-HTR1A. 5-HTR1B, 5-HTR1D, 5-HTR1F, 5-HTR2A, 5-HTR2B, 5-HTR2C, and 5-HTR4) in the bovine digestive tract were measured by use of a quantitative real-time reverse transcription-polymerase chain reaction assay. Results were reported in relation to mRNA expression of the housekeeping gene glyceraldehyde phosphate dehydrogenase (GAPDH).


RESULTS
Mean relative mRNA concentrations for 5-HTR were low (range, 0% to 1.32% of GAPDH), and mRNA that codes for 5-HTR1A was not detected. In the abomasum, mRNA expression was highest for 5-HTR1B and 5-HTR2B, followed by subtypes 1F 2A, 1D, and 4, whereas 5-HTR2C was not detected. In intestinal samples, concentrations of subtypes 1B, 2B, and 4 were highest, followed by 1D, 1F, 2A, and 2C. Relative concentrations of mRNA that code for 5-HTR2A were significantly higher in the abomasum than the intestines, but lower for 5-HTR2B, 5-HTR2C, and 5-HTR4.


CONCLUSIONS
Relative concentrations of mRNA that code for 5-HTRs differ among locations in the gastrointestinal tract of cattle. Understanding differences in the distribution of 5-HTRs in healthy cattle and cattle with gastrointestinal tract disease may lead to improved therapeutic approaches for abomasal and cecal motility disorders.
Meylan
Mireille
M
Clinic for Ruminants, Department of Clinical Veterinary Medicine, Vetsuisse Faculty of Berne, Bremgartenstrasse 109a, 3001 Berne, Switzerland.
Georgieva
Teodora M
TM
Reist
Martin
M
Blum
Jürg W
JW
Martig
Johannes
J
Georgiev
Ivan P
IP
Steiner
Adrian
A
D000704:Analysis of Variance; D000818:Animals; D002417:Cattle / Q000235:genetics / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D041981:Gastrointestinal Tract / Q000378:metabolism*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D044263:Receptors, Serotonin, 5-HT1 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D018076:DNA, Complementary; D012333:RNA, Messenger; D044263:Receptors, Serotonin, 5-HT1; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases