Selective denervation of the aortic and carotid baroreceptors in rats

Author(s)

Castania, Jaci A. ^[1] ; Katayama, Pedro L. ^[1] ; Brognara, Fernanda ^[1] ; Moraes, Davi J. A. ^[1] ; Sabino, Joao Paulo J. ^[2] ; Salgado, Helio C. ^[1]

Affiliation

^[1] Univ Sao Paulo, Ribeirao Preto Med Sch, Dept Physiol, Ave Bandeirantes 3900, BR-14049900 Ribeirao Preto, SP - Brazil

^[2] Univ Fed Piaui, Dept Biophys & Physiol, Teresina, Piaui - Brazil

• Document type: Journal article
• Source: Experimental Physiology; v. 104, n. 9, p. 1335-1342, SEP 2019.
• Web of Science Citations: 0

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. (AU)

• FAPESP's process: 17/05163-6 - Role of the parasympathetic and sympathetic autonomic nervous system in the modulation of sepsis in unanesthetized rats
• Grantee: Fernanda Brognara Penteado Dias
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 13/10484-5 - Electrophysiological and molecular characterization of neurons involved in the generation of respiratory rhythm and pattern of rats during postnatal development
• Grantee: Davi José de Almeida Moraes
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 13/20549-7 - New insights in cardiovascular regulation under physiological and pathophysiological condition
• Grantee: Helio Cesar Salgado
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 15/18511-7 - Role of carotid chemoreceptors in hemodynamic and ventilatory responses to electrical stimulation of the carotid sinus and effects of its chronic inhibition in the development of hypertension in Spontaneously Hypertensive Rats (SHR)
• Grantee: Pedro Lourenço Katayama
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)