Effects of sinoaortic denervation on hemodynamic parameters during natural sleep in rats.
OBJECTIVE
To analyze the role of arterial baroreflex on hemodynamic changes during synchronized and desynchronized sleep phases of natural sleep in rats.


METHODS
Experimental study.


METHODS
Laboratory.


METHODS
Seventeen male Wistar rats.


METHODS
No intervention (control, n = 8) or sinoaortic denervation (SAD, n = 9).


RESULTS
Sleep phases were monitored by electrocorticogram, and blood pressure was measured directly by a catheter in the carotid artery. Cardiac output, as well as total and regional vascular resistances, were determined by measuring the subdiaphragmatic aorta and iliac artery flows with Doppler flow probes, respectively. In contrast to the control group, the SAD group had a strong reduction in blood pressure (-19.9% +/- 2.6% vs -0.7% +/- 2.1%) during desynchronized sleep, and cardiac output showed an exacerbated reduction (-10.4% +/- 3.5% vs 1.1% +/- 1.7%). In SAD rats, total vascular resistance decreased during desynchronized sleep (-10.1% +/- 3.5% vs -1.0% +/- 1.7%), and the increase in regional vascular resistance observed in the control group was abolished (27.5% +/- 8.3% vs -0.8% +/- 9.4%).


CONCLUSIONS
SAD caused profound changes in blood pressure, cardiac output, and total vascular resistance, with a significant increase in muscle vascular resistance during synchronized sleep. Our results suggest that baroreflex plays an important role in maintaining the normal balance of cardiac output and total vascular resistance during sleep.
Silveira
Neide P
NP
Hypertension Unit of the Heart Institute (InCor) do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil.
Moreira
Edson D
ED
Drager
Luciano F
LF
Silva
Gustavo J J
GJ
Krieger
Eduardo M
EM
D000320:Adrenergic Fibers / Q000502:physiology; D000818:Animals; D001011:Aorta / Q000294:innervation*; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D017536:Carotid Artery, Common / Q000294:innervation; D002346:Carotid Sinus / Q000502:physiology*; D003714:Denervation; D006439:Hemodynamics / Q000502:physiology*; D006614:Hindlimb / Q000098:blood supply; D007823:Laryngeal Nerves / Q000502:physiology; D008297:Male; D011311:Pressoreceptors / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000502:physiology; D012890:Sleep / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology*; D018608:Ultrasonography, Doppler; D014630:Vagus Nerve / Q000502:physiology*; D014655:Vascular Resistance / Q000502:physiology; D014851:Wakefulness / Q000502:physiology