Cardiorespiratory responses mediated by the interaction between the peripheral chemoreflex and the muscle mechanoreflex in healthy humans

• Grant number: 16/01155-6
• Support type: Scholarships in Brazil - Master
• Effective date (Start): April 01, 2016
• Effective date (End): June 07, 2017
• Field of knowledge: Biological Sciences - Physiology
• Principal Investigator: Bruno Moreira Silva
• Grantee: Talita Miranda Silva
• Home Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

The peripheral chemoreflex activity augments during exercise compared with rest, both in normoxia and hypoxia, which exacerbates cardiovascular and respiratory responses in humans, maybe contributing to exercise intolerance pathophysiology. The mechanisms responsible for this phenomenon are not clear yet, which limits the development/use of specific strategies to attenuate/revert it. In this sense, it is plausible that the activation of muscle afferents (i.e., mechanoreflex) and the increase in sympathetic activity have some contribution. Therefore, our aim is to test the hypothesis that there is interaction between the peripheral chemoreflex and the muscle mechanoreflex for the regulation of cardiorespiratory variables, which is potentiated under condition of high sympathetic activity. To address this aim, 20 healthy young adults, including men and women, will be enrolled. The subjects will inhale three different gases; one to increase the activity of the peripheral chemoreflex (hypoxia), one to decrease the activity (hyperoxia), and another control (normoxia). During the inhalation the muscle mechanoreflex will be activated, via passive flexion and extension of the knee of the non-dominant limb using an isokinetic dynamometer. Moreover, the inhalation of gases and activation of the muscle mechanoreflex will be conducted with and without immersion of one hand in cold water (3-4o C), in order to change the basal sympathetic activity. Heart rate, stroke volume, beat-by-beat blood pressure, oxygen arterial saturation, ventilation, end tidal pressure of O2 and CO2 will be measured. To confirm that the movement will be done passively we will measure torque and muscle electrical activity.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

PAULA-RIBEIRO, MARCELLE; RIBEIRO, INDYANARA C.; ARANDA, LILIANE C.; SILVA, TALITA M.; COSTA, CAMILA M.; RAMOS, ROBERTA P.; OTA-ARAKAKI, JAQUELINA S.; CRAVO, SERGIO L.; NERY, LUIZ E.; STICKLAND, MICHAEL K.; SILVA, BRUNO M. Carotid chemoreflex activity restrains post-exercise cardiac autonomic control in healthy humans and in patients with pulmonary arterial hypertension. JOURNAL OF PHYSIOLOGY-LONDON, v. 597, n. 5, p. 1347-1360, MAR 1 2019. Web of Science Citations: 0.

SILVA, TALITA M.; ARANDA, LILIANE C.; PAULA-RIBEIRO, MARCELLE; OLIVEIRA, DIOGO M.; MEDEIROS, WLADIMIR M.; VIANNA, LAURO C.; NERY, LUIZ E.; SILVA, BRUNO M. Hyperadditive ventilatory response arising from interaction between the carotid chemoreflex and the muscle mechanoreflex in healthy humans. Journal of Applied Physiology, v. 125, n. 1, p. 215-225, JUL 2018. Web of Science Citations: 6.