title: Differential contribution of aortic and carotid sinus baroreflexes to control of heart rate and renal sympathetic nerve activity.
abstract: We examined the roles of aortic and carotid sinus baroreceptors in control of heart rate (HR) and renal sympathetic nerve activity (RSNA) in 17 decerebrate rats. The baroreflex curves between the changes in mean arterial blood pressure (MAP) and HR or RSNA in response to intravenous injection of phenylephrine (10-20 μg/kg) or nitroprusside (10 μg/kg) were identified before and following sequential denervation of all four baroafferent nerves. The slope of the MAP-HR curve in the pressor range was decreased (P < 0.05) to 31 ± 7% of the control following denervation of bilateral aortic nerves, whereas it remained substantial (72 ± 10%) following denervation of bilateral carotid sinus nerves. The slope for HR became negligible following complete denervation of all four baroafferent nerves. In contrast, the slope of the MAP-RSNA curve decreased as the sequential baroafferent denervation progressed, irrespective of the denervation order, and it remained well as long as any single baroafferent nerve was intact. The similar influences of sequential baroafferent denervation on the responses of HR and RSNA were observed in the depressor range. Thus, it is likely that aortic and carotid sinus baroreceptors play differential roles in control of HR but they contribute similarly to control of RSNA.
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Ishii
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Idesako
authors.forename: Idesako
authors.initials: I
authors.lastname: Mitsuhiro
authors.forename: Kanji
authors.initials: K
authors.lastname: Matsukawa
mesh_terms: D000818:Animals; D062186:Arterial Pressure; D017704:Baroreflex / Q000187:drug effects; D002346:Carotid Sinus / Q000294:innervation*; D003655:Decerebrate State; D006321:Heart / Q000294:innervation*; D006339:Heart Rate / Q000187:drug effects; D007668:Kidney / Q000294:innervation*; D008297:Male; D040542:Mechanotransduction, Cellular; D023421:Models, Animal; D009434:Neural Pathways / Q000502:physiology; D011311:Pressoreceptors / Q000187:drug effects / Q000502:physiology*; D017208:Rats, Wistar; D012850:Sinus of Valsalva / Q000294:innervation*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents