Endothelium, Blood Flow, and Vascular Responses in Large Coronary and Iliac Arteries of the Conscious Dog

Abstract

The majority of insight into mechanisms of endothelium-mediated vascular responses has been gained from experiments in vitro (Furchgott and Zawadzki, 1980; De Mey and Vanhoutte, 1981; De Mey et al., 1982; Furchgott, 1983). It is also important to understand whether these mechanisms apply in the intact conscious animal. This is especially important since isolated vessels in vitro often do not respond in a manner identical to the same vessels examined in vivo (Feigl, 1983; Young and Vatner, 1986b). In this regard our laboratory (Young and Vatner, 1986a,b; 1987) and several others (Lamping et al., 1985a,b; Pohl et al., 1986; Kaiser et al., 1986; Kaiser and Sparks, 1986) have examined the question of endothelium-mediated responses in vivo, studying large arteries to the hindlimb and to the heart. Use of the hindlimb vessels offers the primary advantage of the ability to control or restrict blood flow without severely compromising oxygen delivery to the skeletal muscle of the hindlimb. Furthermore the metabolic requirements of the hindlimb do not dramatically affect the responsiveness of the large vessel, as is the case in the coronary circulation (Macho and Vatner, 1981).