title: Signal transduction of aortic and carotid sinus baroreceptors is not modified by central command during spontaneous motor activity in decerebrate cats.
abstract: Our laboratory has suggested that central command provides selective inhibition of the cardiomotor component of aortic baroreflex at the start of exercise, preserving carotid sinus baroreflex. It is postulated that central command may modify the signal transduction of aortic baroreceptors, so as to decrease aortic baroreceptor input to the cardiovascular centers, and, thereby, can cause the selective inhibition of aortic baroreflex. To test the hypothesis, we directly analyzed the responses in multifiber aortic nerve activity (AoNA) and carotid sinus nerve activity (CsNA) during spontaneous motor activity in decerebrate, paralyzed cats. The increases of 62-104% in mean AoNA and CsNA were found during spontaneous motor activity, in proportion to a rise of 35 ± 3 mmHg (means ± SE) in mean arterial blood pressure (MAP), and had an attenuating tendency by restraining heart rate (HR) at the lower intrinsic frequency of 154 ± 6 beats/min. Brief occlusion of the abdominal aorta was conducted before and during spontaneous motor activity to produce a mechanically evoked increase in MAP and, thereby, to examine the stimulus-response relationship of arterial baroreceptors. Although the sensitivity of the MAP-HR baroreflex curve was markedly blunted during spontaneous motor activity, the stimulus-response relationships of AoNA and CsNA were not influenced by spontaneous motor activity, irrespective of the absence or presence of the HR restraint. Thus, it is concluded that aortic and carotid sinus baroreceptors can code beat-by-beat blood pressure during spontaneous motor activity in decerebrate cats and that central command is unlikely to modulate the signal transduction of arterial baroreceptors.
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan matsuk@hiroshima-u.ac.jp.
authors.forename: Kanji
authors.initials: K
authors.lastname: Matsukawa
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Ishii
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan.
authors.forename: Akito
authors.initials: A
authors.lastname: Kadowaki
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ishida
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Idesako
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan.
authors.forename: Nan
authors.initials: N
authors.lastname: Liang
mesh_terms: D000818:Animals; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D002346:Carotid Sinus / Q000502:physiology*; D002415:Cats; D002490:Central Nervous System / Q000502:physiology* / Q000503:physiopathology; D002531:Cerebellum / Q000503:physiopathology / Q000601:surgery; D003655:Decerebrate State / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D023421:Models, Animal; D009043:Motor Activity / Q000502:physiology*; D011311:Pressoreceptors / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D012850:Sinus of Valsalva / Q000502:physiology*
keywords: aortic baroreflex; arterial baroreceptors; carotid sinus baroreflex; central command; exercise