AJP - Regulatory, Integrative and Comparative Physiology, Vol 268, Issue 2 382-R388, Copyright © 1995 by American Physiological Society
Assessment of spontaneous baroreflex sensitivity in rats a new method using the concept of statistical dependence
C. Cerutti, M. Ducher, P. Lantelme, M. P. Gustin and C. Paultre
Department of Physiology and Clinical Pharmacology, Faculty of Pharmacy, Centre National de la Recherche Scientifique, Unite de Recherche Associee 1483, Lyon, France.
A new method was developed to evaluate the cardiac baroreflex sensitivity
(BRS) from spontaneous mean arterial pressure (MAP) and heart rate (HR)
changes in conscious rats. It relies on the determination of the
statistical dependence between MAP and HR values. In 13 control rats, 12
rats with a pharmacologically induced hypertension, and 7 rats with a
chronic sinoaortic denervation (SAD), dependent (MAP, HR) couples related
to the baroreflex activity were selected to determine the spontaneous BRS
(Sp-BRS). In control and hypertensive rats, pharmacological BRS (Ph-BRS)
was estimated using graded bolus intravenous doses of vasoactive drugs.
Ph-BRS was significantly lower in hypertensive than in control rats. Sp-BRS
was determined in 10 control and 10 hypertensive rats and was strongly
correlated with Ph-BRS (r = 0.83, n = 20, P < 0.0001). Sp-BRS could be
evaluated in six SAD rats and was profoundly decreased (-86%, P < 0.001)
compared with control rats. In conclusion, this work validates the
estimation of the cardiac BRS from spontaneous MAP and HR variations with
use of (MAP, HR) couples of values that are statistically dependent.
