Distribution of the neurokinin-1 receptor in equine intestinal smooth muscle.
BACKGROUND
Tachykinins have profound effects on equine intestinal motility, but the distribution of the neurokinin receptors (NKRs) through which they act is unknown. This study reports the distribution of one of these receptors, the neurokinin-1 receptor (NK1R), in smooth muscle throughout the equine intestinal tract.


OBJECTIVE
To quantify the distribution of the NK1R, based upon mRNA expression, in smooth muscle of different regions of the equine intestinal tract.


METHODS
Nine regions of the intestinal tract were sampled in 5 mature horses. Total RNA was isolated from smooth muscle and reverse transcribed; NK1R mRNA was then quantified using real-time PCR.


RESULTS
NK1R mRNA was found at all levels of the sampled intestinal tract. The smooth muscle of the proximal small intestine and the ventral colon exhibited the highest level of NK1R mRNA expression in the equine intestinal tract.


CONCLUSIONS
Tachykinins probably affect intestinal contractility and propulsion in the proximal small intestine and in the ventral colon.
Solinger
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Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada.
Sonea
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IM
D000818:Animals; D001483:Base Sequence; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology*; D006734:Horse Diseases / Q000188:drug therapy / Q000517:prevention & control; D006736:Horses; D045823:Ileus / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary; D007150:Immunohistochemistry / Q000662:veterinary; D007413:Intestinal Mucosa; D008297:Male; D009130:Muscle, Smooth / Q000166:cytology / Q000502:physiology*; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D012333:RNA, Messenger / Q000378:metabolism*; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D015320:Tachykinins / Q000378:metabolism / Q000502:physiology*; D014018:Tissue Distribution
D012333:RNA, Messenger; D018040:Receptors, Neurokinin-1; D015320:Tachykinins