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Intestinal Vascular Responses to Dopamine During Fentanyl‐Nitrous Oxide Anaesthesia, Supplemented with Dixyrazin
Author(s) -
Biber B.,
Martner J.,
Nilsson H.,
Redfors S.,
Sjöwall H.,
Winsö O.
Publication year - 1983
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1983.tb01947.x
Subject(s) - dopamine , vasoconstriction , chloralose , medicine , vasodilation , anesthesia , fentanyl , renal blood flow , vascular resistance , blood pressure , hemodynamics , endocrinology
Intestinal haemodynamics in response to continuous i.v. administration of dopamine were investigated in cats anaesthetized with fentanyl‐nitrous oxide either with or without supplement of dixyrazin. A dose‐dependent vasodilatation was observed in the dopamine dose range 2.5–35 μg‐kg ‐1 min ‐1 and the subsequent maximal intestinal blood flow increase was 121%. No net intestinal vasoconstriction was evident even at the largest dopamine doses, although the vascular response reached a plateau at 17.5 μg‐kg ‐1 min ‐1 . Control experiments during chloralose anaesthesia gave similar results. Changes in mean arterial pressure and heart rate were small. Renal blood flow was virtually unchanged at dopamine doses below 10 μg‐kg ‐1 min ‐1 , while renal vasoconstriction was evident following dopamine doses above that level. The addition of i.v. dixyrazin (0.15‐0.30 mg kg ‐1 ) to the fentanyl‐nitrous oxide anaesthesia substantially potentiated the intestinal vasodilator response to i.v. dopamine and the maximal blood flow increase was 183% at 10–15 μg kg ‐1 min ‐1 . In vitro experiments using mesenteric resistance vessels from the rat demonstrated a dose‐dependent relaxation to dopamine. At very large doses this response was counteracted, but not reversed into vasoconstriction by dopamine‐induced a‐adrenergic stimulation.