title: Uniformity in dynamic baroreflex regulation of left and right cardiac sympathetic nerve activities.
abstract: Functional laterality of cardiac sympathetic nerve stimulation in chronotropic and inotropic effects is well known. Whether left (LSNA) and right (RSNA) cardiac sympathetic nerve activities show laterality during dynamic baroreflex activation remains to be determined. In nine anesthetized, vagotomized, and aortic-denervated rabbits, we randomly perturbed intracarotid sinus pressure (CSP) in both carotid sinus regions while simultaneously recording LSNA and RSNA. The baroreflex neural arc transfer function from CSP to LSNA and from CSP to RSNA revealed derivative characteristics, i.e., the magnitude of LSNA and RSNA responses became greater as the input frequency of CSP perturbation increased. The average slope of increasing gain in the frequencies between 0.03 and 0.3 Hz showed no difference between LSNA and RSNA responses (9.7 +/- 2.9 vs. 9.7 +/- 3.1 dB/decade, means +/- SD). The amplitude ratio and phase difference between LSNA and RSNA approximated unity and zero radians, respectively, in the frequencies from 0.01 to 1 Hz. In addition, the LSNA-RSNA relationship during stepwise CSP perturbation from 40 to 160 mmHg showed a straight line (r(2) ranged from 0.969 to 0.999). These findings indicate no laterality in the dynamic as well as static baroreflex regulation of LSNA and RSNA as far as grouped axonal activity is concerned.
authors.affiliation: Department of Cardiovascular Dynamics, National Cardiovascular Center Research Institute, Osaka 565-8565, Japan. torukawa@res.ncvc.go.jp
authors.forename: Toru
authors.initials: T
authors.lastname: Kawada
authors.forename: Kazunori
authors.initials: K
authors.lastname: Uemura
authors.forename: Koji
authors.initials: K
authors.lastname: Kashihara
authors.forename: Yintie
authors.initials: Y
authors.lastname: Jin
authors.forename: Meihua
authors.initials: M
authors.lastname: Li
authors.forename: Can
authors.initials: C
authors.lastname: Zheng
authors.forename: Masaru
authors.initials: M
authors.lastname: Sugimachi
authors.forename: Kenji
authors.initials: K
authors.lastname: Sunagawa
mesh_terms: D000320:Adrenergic Fibers / Q000502:physiology*; D000818:Animals; D001011:Aorta / Q000294:innervation / Q000502:physiology; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure; D002346:Carotid Sinus / Q000502:physiology; D005260:Female; D006321:Heart / Q000294:innervation* / Q000502:physiology*; D008297:Male; D011817:Rabbits; D013997:Time Factors; D014628:Vagotomy