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The role of carotid chemoreceptors in the effects of hypoxia on renal blood flow in the late gestation sheep fetus
Author(s) -
Green LR,
Bennet L,
Robson S,
Hanson MA
Publication year - 1997
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.1997.sp004007
Subject(s) - fetus , hypoxia (environmental) , vasoconstriction , medicine , renal blood flow , endocrinology , gestation , kidney , vasodilation , blood flow , biology , pregnancy , chemistry , oxygen , genetics , organic chemistry
Previous studies of the effect of hypoxia on fetal renal haemodynamics have demonstrated a fall, a rise or no change in renal blood flow (RBF). The underlying mechanisms are not understood but involve a balance between neural vasoconstrictor and opposing vasodilator mechanisms. Since carotid chemoreflex mechanisms contribute to vasoconstriction in other fetal vascular beds and in the adult renal vasculature, we examined their effects on RBF during 1 h of acute hypoxia in late gestation fetal sheep (n = 12). Renal blood flow was measured continuously and urine collected at 15 min intervals. Seven fetuses underwent bilateral section of the carotid sinus nerves (CSD fetuses). During hypoxia CSD fetuses showed a transient initial rise in RBF (P < 0.05) and then a subsequent fall (P < 0.05) to levels comparable with that recorded in intact fetuses. There was no change in urine output in either intact or CSD fetuses during hypoxia. Thus the initial fall in RBF during hypoxia is a carotid chemoreflex but other mechanisms, e.g. vasoconstrictor hormones, contribute to the sustained response.