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Selective denervation of the aortic and carotid baroreceptors in rats
Author(s) -
Castania Jaci A.,
Katayama Pedro L.,
Brognara Fernanda,
Moraes Davi J. A.,
Sabino João Paulo J.,
Salgado Helio C.
Publication year - 2019
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/ep087764
Subject(s) - baroreceptor , phenylephrine , denervation , carotid sinus , baroreflex , medicine , reflex bradycardia , anesthesia , chemoreceptor , aorta , cardiology , reflex , blood pressure , heart rate , receptor
New FindingsWhat is the central question of this study? The traditional surgical approach for sino‐aortic denervation in rats leads to simultaneous carotid baroreceptor and chemoreceptor deactivation, which does not permit their individual study in different situations.What is the main finding and its importance? We have described a new surgical approach capable of selective denervation of the arterial (aortic and carotid) baroreceptors, keeping the carotid bodies (chemoreceptors) intact. It is understood that this technique might be a useful tool for investigating the relative role of the baro‐ and chemoreceptors in several physiological and pathophysiological conditions.Abstract Studies have demonstrated that the traditional surgical approach for sino‐aortic denervation in rats leads to simultaneous carotid baroreceptor and chemoreceptor deactivation. The present study reports a new surgical approach to denervate the aortic and the carotid baroreceptors selectively, keeping the carotid bodies (peripheral chemoreceptors) intact. Wistar rats were subjected to specific aortic and carotid baroreceptor denervation (BAROS‐X) or sham surgery (SHAM). Baroreflex activation was achieved by i.v . administration of phenylephrine, whereas peripheral chemoreflex activation was produced by i.v . administration of potassium cyanide. The SHAM and BAROS‐X rats displayed significant hypertensive responses to phenylephrine administration. However, the reflex bradycardia following the hypertensive response caused by phenylephrine was remarkable in SHAM, but not significant in the BAROS‐X animals, confirming the efficacy of the surgical procedure to abolish the baroreflex. In addition, the baroreflex activation elicited by phenylephrine increased carotid sinus nerve activity only in SHAM, but not in the BAROS‐X animals, providing support to the notion that the baroreceptor afferents were absent. Instead, the classical peripheral chemoreflex hypertensive and bradycardic responses to potassium cyanide were similar in both groups, suggesting that the carotid body chemoreceptors were preserved after BAROS‐X. In summary, we describe a new surgical approach in which only the baroreceptors are eliminated, while the carotid chemoreceptors are preserved. Therefore, it is understood that this procedure is potentially a useful tool for examining the relative roles of the arterial baroreceptors versus the chemoreceptors in several pathophysiological conditions, for instance, arterial hypertension and heart failure.