Sustained hypoxia in mice increases parasympathetic but not sympathetic tone

Author(s)

Souza, Juliana R. ; de Oliveira, Mauro ; Machado, Benedito H.

• Document type: Journal article
• Source: CURRENT RESEARCH IN PHYSIOLOGY; v. 5, p. 8-pg., 2022-01-01.

Abstract

The autonomic profile of mice submitted to sustained hypoxia (SH) was not yet fully evaluated. Herein, we characterized the cardiovascular and autonomic profile of conscious freely moving mice submitted to SH using two sequential experimental protocols to evaluate the parasympathetic and sympathetic tone to the heart and the sympathetic tone to the vascular resistance. In the first protocol the sequence of antagonists was methyl-atropine followed by propranolol and then by prazosin, while in the second protocol the sequence was propranolol followed by methyl-atropine and then by prazosin. In SH the baseline heart rate was significantly lower than in control mice and the antagonism of the parasympathetic and sympathetic tone to the heart in both experimental protocols indicated an increased parasympathetic tone in SH mice and no changes in the sympathetic tone. Antagonism of the sympathetic tone to the vascular resistance with prazosin produced similar changes in arterial pressure in control and SH mice. Altogether these findings support the concept that mice submitted to SH present a significant increase in the parasympathetic but not in the sympathetic tone, which may explain why the baseline arterial pressure was not increased in SH mice. (AU)

• FAPESP's process: 19/21916-0 - Characterization of the cardiovascular and respiratory alterations of mice previously submitted to sustained hypoxia
• Grantee: Juliana Reis Souza
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 18/15957-2 - Astrocytic modulation on brainstem neurons involved with generation and control of sympathetic and respiratory activities in rodents submitted to hypoxia
• Grantee: Benedito Honorio Machado
• Support Opportunities: Research Projects - Thematic Grants