title: The ex vivo isolated skeletal microvessel preparation for investigation of vascular reactivity.
abstract: The isolated  microvessel preparation is an ex vivo preparation that allows for examination of the different contributions of  factors that control vessel diameter, and thus, perfusion resistance(1-5).  This is a classic experimental preparation that was, in large measure,  initially described by Uchida et al.(15)  several decades ago. This initial  description provided the basis for the techniques that was extensively modified  and enhanced, primarily in the laboratory of Dr. Brian Duling at the University  of Virginia(6-8), and we present a current approach in the following  pages. This preparation will specifically refer to the gracilis arteriole in a  rat as the microvessel of choice, but the basic preparation can readily be  applied to vessels isolated from nearly any other tissue or organ across  species(9-13). Mechanical  (i.e., dimensional) changes in the isolated microvessels can easily be  evaluated in response to a broad array of physiological (e.g., hypoxia, intravascular  pressure, or shear) or pharmacological challenges, and can provide insight into  mechanistic elements comprising integrated responses in an intact, although ex vivo, tissue. The significance of this  method is that it allows for facile manipulation of the influences on the  integrated regulation of microvessel diameter, while also allowing for the control  of many of the contributions from other sources, including intravascular pressure  (myogenic), autonomic innervation, hemodynamic (e.g., shear stress), endothelial  dependent or independent stimuli, hormonal, and parenchymal influences, to provide  a partial list. Under appropriate  experimental conditions and with appropriate goals, this can serve as an  advantage over in vivo or in situ tissue/organ preparations, which  do not readily allow for the facile control of broader systemic variables.     The major limitation of this preparation is essentially the consequence of its strengths.  By definition, the behavior of these vessels is being studied under conditions where many of the most significant contributors to the regulation of vascular resistance have been removed, including neural, humoral, metabolic, etc.  As such, the investigator is cautioned to avoid over-interpretation and extrapolation of the data that are collected utilizing this preparation.  The other significant area of concern with regard to this preparation is that it can be very easy to damage cellular components such as the endothelial lining or the vascular smooth muscle, such that variable source of error can be introduced.  It is strongly recommended that the individual investigator utilize appropriate measurements to ensure the quality of the preparation, both at the initiation of the experiment and periodically throughout the course of a protocol.
authors.affiliation: Department of Physiology and Pharmacology, Center for Cardiovascular and Respiratory Sciences, West Virginia University, USA.
authors.forename: Joshua T
authors.initials: JT
authors.lastname: Butcher
authors.forename: Adam G
authors.initials: AG
authors.lastname: Goodwill
authors.forename: Jefferson C
authors.initials: JC
authors.lastname: Frisbee
mesh_terms: D000818:Animals; D055806:Microvessels / Q000502:physiology* / Q000601:surgery*; D018482:Muscle, Skeletal / Q000098:blood supply*; D051381:Rats