title: Central and baroreflex control of heart period during the wake-sleep cycle in spontaneously hypertensive rats.
abstract: We investigated whether the relative contribution of the baroreflex and central commands to the control of heart period differs between spontaneously hypertensive rats (SHR) and Wistar-Kyoto normotensive rats (WKY) during physiological behavior. Rats were instrumented with an arterial catheter and with electrodes for discriminating wakefulness, nonrapid eye movement sleep (NREMS), and rapid eye movement sleep (REMS). The cross-correlation function (CCF) between spontaneous fluctuations of heart period and mean arterial pressure was computed at frequencies <0.2 Hz. The baroreflex determines a positive correlation between heart period and previous pressure values. This pattern was observed in the CCF during quiet wakefulness (QW) and NREMS, and in QW, it was accompanied by a pronounced negative correlation between heart period and subsequent pressure values. The relative baroreflex contribution to the control of heart period, estimated from the positive peak value of the CCF, was lower in SHR than in WKY during QW but not during NREMS. During REMS, the CCF showed a negative correlation between heart period and both previous and subsequent pressure values, reflecting the prevalence of central autonomic commands. The relative contribution of central commands to the control of heart period, estimated from the negative peak value of the CCF, was lower in SHR than in WKY during REMS. These results suggest that during QW and REMS, the control of heart period exerted by the baroreflex and central commands, respectively, is less effective in SHR than in WKY. This difference is not apparent in a behavioral state of autonomic stability such as NREMS.
authors: Dipartimento di Fisiologia Umana e Generale, Università di Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy.
authors: Chiara
authors: C
authors: Berteotti
authors: Valentina
authors: V
authors: Asti
authors: Vera
authors: V
authors: Ferrari
authors: Carlo
authors: C
authors: Franzini
authors: Pierluigi
authors: P
authors: Lenzi
authors: Giovanna
authors: G
authors: Zoccoli
authors: Alessandro
authors: A
authors: Silvani
mesh_terms: D000818:Animals; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004576:Electromyography; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012890:Sleep / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology; D013045:Species Specificity; D014851:Wakefulness / Q000502:physiology*