Interaction between baroreflex and chemoreflex in the cardiorespiratory responses to stimulation of the carotid sinus/nerve in conscious rats

Autor(es)

Katayama, Pedro L. ^[1] ; Castania, Jaci A. ^[1] ; Fazan Jr, Rubens ; Salgado, Helio C. ^[2]

Afiliação do(s) autor(es)

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

^[2] Fazan Jr, Jr., Rubens, Univ Sao Paulo, Dept Physiol, Ribeirao Preto Med Sch, Av Bandeirantes 3900, BR-14049900 Ribeirao Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: AUTONOMIC NEUROSCIENCE-BASIC & CLINICAL; v. 216, p. 17-24, JAN 2019.
• Citações Web of Science: 1

Resumo

Electrical stimulation of the carotid baroreflex has been thoroughly investigated for treating drug-resistant hypertension in humans. However, a previous study from our laboratory, performed in conscious rats, has demonstrated that electrical stimulation of the carotid sinus/nerve (CS) activated both the carotid baroreflex as well as the carotid chemoreflex, resulting in hypotension. Additionally, we also demonstrated that the carotid chemoreceptor deactivation potentiated this hypotensive response. Therefore, to further investigate this carotid baroreflex/chemoreflex interaction, besides the hemodynamic responses, we evaluated the respiratory responses to the electrical stimulation of the CS in both intact (CONT) and carotid chemoreceptors deactivated (CHEMO-X) conscious rats. CONT rats showed increased ventilation in response to electrical stimulation of the CS as measured by the respiratory frequency (fR), tidal volume (V-T) and minute ventilation (V-E), suggesting a carotid chemoreflex activation. The carotid chemoreceptor deactivation abolished all respiratory responses to the electrical stimulation of the CS. Regarding the hemodynamic responses, the electrical stimulation of the CS caused hypotensive responses in CONT rats, which were potentiated by the carotid chemoreceptors deactivation. Heart rate (HR) responses did not differ between groups. In conclusion, the present study showed that the electrical stimulation of the CS, in conscious rats, activates both the carotid baroreflex and the carotid chemoreflex driving an increase in ventilation and a decrease in AP. These findings further contribute to our understanding of the electrical stimulation of CS. (AU)

• Processo FAPESP: 15/18511-7 - Papel dos quimiorreceptores carotídeos nas respostas hemodinâmicas e ventilatórias à estimulação elétrica do seio carotídeo, e efeitos da sua inibição crônica no desenvolvimento da hipertensão arterial em ratos com hipertensão espontânea (SHR)
• Beneficiário: Pedro Lourenço Katayama
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto