Effects of hypovolemia on blood flow, arterial [HCO3-], and HCO3- output in the rat duodenum.
The effects of bleeding-induced hypovolemia on duodenal blood flow (microsphere technique), arterial [HCO3-], and duodenal HCO3- secretion (in situ titration) were investigated in chloralose-anesthetized rats. A 10% decrease in blood volume reduced duodenal HCO3- secretion by 44%, duodenal blood flow by 31%, and arterial [HCO3-] by 11%. In a group with cervically cut vagal nerves, basal duodenal HCO3- secretion was greater than 50% lower compared with controls. Basal blood flow and arterial [HCO3-] were on similar levels as in nonvagotomized animals. Furthermore, bleeding failed to lower duodenal alkaline output in rats with cut vagal nerves, although blood flow and arterial [HCO3-] were reduced to a similar extent as in the vagally intact controls. In a yohimbine-treated group, a 10% bleeding reduced duodenal blood flow by 28% and arterial [HCO3-] by 7% without influencing duodenal HCO3- secretion. We suggest that the hypovolemia-induced inhibition of duodenal alkaline secretion is not caused by a decrease in blood and/or arterial [HCO3-]. Instead, other factors may be of importance, for example, neural effects on enteric secretomotor neurons or directly on the secreting epithelium.
Jönson
C
C
Department of Physiology, University of Göteborg, Sweden.
Holm
L
L
Jansson
T
T
Fändriks
L
L
D000818:Animals; D001639:Bicarbonates / Q000097:blood / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D004386:Duodenum / Q000098:blood supply / Q000502:physiology / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects; D006470:Hemorrhage / Q000503:physiopathology; D008297:Male; D009130:Muscle, Smooth / Q000098:blood supply / Q000502:physiology / Q000503:physiopathology; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012039:Regional Blood Flow; D012769:Shock / Q000503:physiopathology*; D014630:Vagus Nerve / Q000502:physiology; D015016:Yohimbine / Q000494:pharmacology
D001639:Bicarbonates; D015016:Yohimbine