Effects of chronic bile-duct ligation on the baroreceptor reflex in dogs.
The purpose of the present experiments was to examine the effects of chronic bile-duct ligation (CBDL) on the baroreceptor reflex system. The open-loop gain (G) of the baroreceptor reflex system and pressor response to noradrenaline were measured in seven dogs with CBDL for 4 to 6 weeks, and the data were compared with those of seven control dogs. The liver function of the CBDL-dogs was significantly impaired. G was assessed as (delta API/delta APS)-1, where delta API and delta APS represent the immediate and steady-state decreases in arterial pressure at the aortic arch following a fast step-wise reduction in blood volume. The value of G was 8.8 +/- 0.9 (mean +/- SE) in the control-group and 5.3 +/- 2.1 in the CBDL-group (p less than 0.05). The maximum increase in arterial pressure in response to a bolus injection of noradrenaline (0.5 micrograms/kg i.v.) was 29.3 +/- 4.4 mm Hg in the control-group and 19.7 +/- 1.6 mm Hg in the CBDL-group (p less than 0.05). These findings suggest that CBDL leads to a decrease in responsiveness of the vascular smooth muscle to noradrenaline which in turn results in a decrease in open-loop gain of the baroreceptor reflex system.
Kosuga
H
H
Department of Physiology, Kagawa Medical School, Japan.
Hosomi
H
H
Morita
H
H
Saito
Y
Y
D000818:Animals; D001652:Bile Ducts / Q000502:physiology*; D001663:Bilirubin / Q000097:blood; D001794:Blood Pressure; D004285:Dogs; D005260:Female; D006470:Hemorrhage / Q000503:physiopathology; D008111:Liver Function Tests; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D011311:Pressoreceptors / Q000502:physiology*; D012016:Reference Values; D012018:Reflex / Q000187:drug effects
D001663:Bilirubin; D009638:Norepinephrine