Intestinal blood flow is controlled by both feed arteries and microcirculatory resistance vessels in freely moving rats.

Abstract

1. In freely moving rats, intestinal blood flow, aortic blood pressure and blood pressure at the base of mesenteric arcades were measured simultaneously so as to determine the role of feed arteries and of the microcirculation in the control of intestinal vascular resistance. Segmental resistances of feed arteries (Rfeed) and of microcirculatory vessels (Rmicro) were calculated. 2. At rest, Rfeed and Rmicro were 32 and 68%, respectively, of the total intestinal vascular resistance.3. Injection of noradrenaline (2 jug Intravenous noradrenaline and adrenaline responses were attenuated. 6. We conclude that in freely moving rats, mesenteric feed arteries, as well as microcirculatory vessels, are true resistance vessels, and that blood flow.

Location of Resistance Arteries

“…We have done a number of experiments in the rat using the technique described in figure 1, of which a video surveillance experiment (fig. 3) provides in our view rather convincing support for feed arteries and intramural microvessels contributing to intestinal blood flow control on equal terms [17]. In this experiment, while rats were resting, central and microvascular blood pressures were stable, but during periods of some activity, such as drinking and changing position, blood pressure rose by 5–10 mm Hg and mesenteric blood flow fell transiently by 10–20%.…”

“…In this experiment, while rats were resting, central and microvascular blood pressures were stable, but during periods of some activity, such as drinking and changing position, blood pressure rose by 5–10 mm Hg and mesenteric blood flow fell transiently by 10–20%. The resulting 20–30% rise in mesenteric resistance during such activity was equally distributed between feed arteries and microvasculature [17]. As indicated in figure 3, startling these rats resulted in a balanced constriction of feed arteries and microvasculature, although the feed arteries tended to sustain the constriction [17].…”

“…The resulting 20–30% rise in mesenteric resistance during such activity was equally distributed between feed arteries and microvasculature [17]. As indicated in figure 3, startling these rats resulted in a balanced constriction of feed arteries and microvasculature, although the feed arteries tended to sustain the constriction [17]. Blockade of sympathetic α 1 -adrenoceptors with prazosin inhibited these responses, although the visible physical response of the rats was not different before and during α 1 -blockade.…”

“…Apart from certain vascular beds, for example the retina [15], such beds can only be visualized by exteriorization, thus implying the use of anesthesia; with the hamster back-flap model [16], however, this has been possible in conscious animals. The direct technique requires the implantation of a flow transducer together with a pressure catheter [17]. …”

Endothelial dysfunction in rat mesenteric artery after regional cardiac ischaemia–reperfusion

“…Mesenteric arteries are an essential constituent of peripheral resistance vessels and are involved in the modulation of systemic blood pressure (Fenger-Gron et al 1997). Therefore, the aim of the present study was to determine whether regional cardiac I/R influences the vascular responses in remote arteries, such as mesenteric arteries, that have an important role in the circulatory system.…”