Submitted to: Journal of Visualized Experiments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2014
Publication Date: 10/7/2014
Citation: Klotz, J.L., Barnes, A.J. 2014. Isolating and using sections of bovine mesenteric artery and vein as a bioassay to test for vasoactivity in the small intestine. Journal of Visualized Experiments. 92:e52020.
Interpretive Summary: The small intestine is frequently exposed to toxins that can influence blood flow and negatively impact the function of nutrient absorption. A bioassay was developed and describe in this manuscript using a multimyograph and bovine mesenteric artery and vein isolates. This bioassay will permit the evaluation compounds or toxins of interest for vasoactivity. In this particular case, the bioassay will be used to screen ergot alkaloid for vasoactivity in the mesenteric vasculature that supports the small intestine. Eventual use of the bioassay will be as a tool to aid in the determination of how ergot alkaloid exposure (specifically fescue toxicosis) affects the function of the small intestine.
Technical Abstract: Mammalian gastrointestinal systems are constantly exposed to compounds (desirable and undesirable) that can have an effect on blood flow to and from that system. Changes in blood flow to the small intestine can result in effects on the absorptive functions of the organ. Particular interest in toxins liberated from feedstuffs through fermentative and digestive processes has developed in ruminants as an area where productive efficiencies could be improved. The video associated with this article describes an in vitro bioassay developed to screen compounds for vasoactivity in isolated cross-sections of bovine mesenteric artery and vein using a multimyograph. Once the blood vessels are mounted and equilibrated in the myograph, the bioassay itself can be used: as a screening tool to evaluate the contractile response or vasoactivity of compounds of interest; determine the presence of receptor types by pharmacologically targeting receptors with specific agonists; determine the role of a receptor with the presence of one or more antagonists; or determine potential interactions of compounds of interest with antagonists. Through all of this, data are collected real-time, tissue collected from a single animal can be exposed to a large number of different experimental treatments (an in vitro advantage), and represents vasculature on either side of the capillary bed to provide an accurate picture of what could be happening in the afferent and efferent blood supply supporting the small intestine.